JP2006206870A - Raw material for cerium type abrasive and manufacturing method of raw material for cerium type abrasive, cerium type abrasive and manufacturing method of cerium type abrasive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a raw material for a cerium type abrasive capable of forming a polished surface with a high accuracy, while keeping an polishing speed, by using a raw material for the cerium type abrasive in which a fluorine concentration is reduced. <P>SOLUTION: The raw material for the cerium type abrasive contains content of cerium oxide of ≥30 mass% per the total rare earth oxide (TREO), fluorine concentration of ≤0.5 mass% per the TREO and further contains a rare earth compound including carbonate radical, and its sedimentation volume is ≥30 mL per 100 mL of the raw material slurry when the raw material slurry mixed with pure water to be made the TREO concentration of 126 g/L is settled for 10 min. The raw material for the abrasive preferably has a standing apparent specific volume of 1.0-3.0 mL/g after drying for 12 hr at 120°C and further content of a hexane extract measured by dissolving it in hydrochloric acid to be preferably to be ≤700 mass ppm based on the TREO. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cerium-based abrasive material, a method for producing the same, and a cerium-based abrasive material produced from the cerium-based abrasive material.

A cerium-based abrasive (hereinafter sometimes simply referred to as an abrasive) is composed of abrasive particles composed of cerium oxide (CeO ₂ ) particles, which are main components, and other rare earth metal oxide particles. It is used for polishing various glass materials. In particular, it has recently been used for polishing glass materials used in electrical and electronic equipment such as glass for magnetic recording media such as hard disks and glass substrates for liquid crystal displays (LCDs), and its application fields are expanding.

  As a method for producing a cerium-based abrasive, first, the raw material for the abrasive is pulverized, subjected to chemical treatment as necessary, and then heated at high temperature to be baked to sinter the raw material particles. Abrasive material having a desired particle size and particle size distribution is produced by pulverization and classification as appropriate.

  Here, as a raw material for the cerium-based abrasive, conventionally, a natural raw material called bastonite concentrate obtained by selecting a rare earth ore called bastonite has been generally used. However, for the purpose of improving the performance of the abrasives produced in recent years and interest in environmental problems, recently, raw materials for abrasives that are extracted from bastonite ore and relatively inexpensive Chinese complex ore are used. It is being done.

For example, Patent Document 1 discloses a light rare earth material mainly composed of cerium in which the content of alkali metal, alkaline earth metal, and radioactive material is reduced. In this raw material for abrasives, consideration is given to dealing with environmental problems by removing radioactive substances and fluorine contained in bust nesitet, and when it is used as an abrasive, it affects the generation of abrasive scratches. The performance of abrasives is improved by removing alkali metals and alkaline earth metals.
JP 2004-2870 A

Further, the applicant of the present application discloses an abrasive material described in Patent Document 2 as an abrasive material having excellent polishing power and polishing accuracy. This raw material for abrasives is produced by calcining a rare earth compound (cerium-based rare earth carbonate) produced from bastonite, etc., and changing a part thereof to a cerium-based rare earth oxide at 1000 ° C. It is a cerium-based abrasive raw material having a loss on ignition of 0.5 to 25% on a dry mass basis when heated for 1 hour.
Japanese Patent No. 3365993

  By the way, not only cerium-based abrasives but also all abrasive materials are required to be able to form a highly accurate polished surface at a high polishing rate without causing scratches on the polished surface. In particular, cerium-based abrasives are increasingly applied to polishing of magnetic recording medium glass and the like as described above, and the demand is strong.

  However, although the raw material for polishing material described in Patent Document 1 is useful in consideration of environmental problems, the polishing material produced thereby has a low polishing speed, and the generation of polishing flaws cannot be sufficiently suppressed. In addition, with regard to the raw material described in Patent Document 2, it is possible to efficiently produce an abrasive material that is superior in polishing speed and polished surface accuracy than the raw material described in Patent Document 1. However, as recording media such as hard disks increase in density and LCD plates become more accurate and precise, polishing materials for finishing polishing are required to be able to form a polished surface with higher accuracy than ever. Yes. Therefore, further improvement is required for the raw material for abrasives.

  The present invention has been made under the background as described above, and is a raw material applied to a cerium-based abrasive, which can form a highly accurate polished surface while maintaining the polishing speed. It aims at providing what enables manufacture of this. Moreover, it aims at clarifying the manufacturing method of such a raw material for abrasives.

  In order to solve the above-mentioned problems, the present inventors examined the relationship between various characteristics of a cerium-based abrasive material and the polishing characteristics when used as an abrasive. The inventors of the present invention have arrived at the present invention by paying attention between the sedimentation volume, which is a characteristic when the raw material for the abrasive is mixed with water to form a raw material slurry, and the abrasive characteristic of the abrasive.

  That is, the present invention provides a cerium-based abrasive having a cerium oxide content of 30% by mass or more with respect to total rare earth oxide (TREO) and a fluorine concentration of 0.5% by mass or less with respect to TREO and containing a rare earth compound containing a carbonate radical. A cerium-based abrasive that has a sedimentation volume of 30 mL or more with respect to 100 mL of the raw material slurry when the raw material slurry mixed with pure water so as to have a TREO concentration of 126 g / L is allowed to stand for 10 minutes. Raw material.

  The reason why the settling volume of the raw material for the abrasive is set to 30 mL or more with respect to 100 mL of the raw material slurry is that when it is less than 30 mL, the polishing accuracy of the manufactured abrasive is lowered and a problem of occurrence of scratches occurs. On the other hand, the upper limit of the sedimentation volume is not particularly limited from the viewpoint of polishing accuracy. However, if the sedimentation volume is too large, the polishing speed becomes low and efficient polishing work cannot be performed. Therefore, considering these points, the sedimentation volume is preferably 30 to 90 mL, more preferably 30 to 70 mL, and even more preferably 40 to 60 mL.

  In the present invention, the slurry concentration, which is a measurement standard of the sedimentation volume, is set to 126 g / L for the following reason. That is, in the case of a typical cerium-based abrasive raw material (TREO 45 mass%), in a slurry in which the raw material and water are mixed at a mass ratio of 1: 3, the difference in the sedimentation volume due to the raw material tends to clearly appear. The difference between the sediment volume of the raw material and the performance of the abrasive produced therefrom is easy to understand. This is because the TREO concentration of the slurry in which the raw material and water are mixed at a mass ratio of 1: 3 is about 126 g / L. However, the abrasive raw material according to the present invention may contain moisture, and it is difficult to accurately set the TREO concentration of the slurry to 126 g / L. Therefore, by actually setting the TREO concentration to 126 g / L and setting it within the range of 126 ± 5 g / L, the error in the measured sedimentation volume is reduced, and it can be used as an evaluation standard for abrasive raw materials. A value can be obtained.

  As a method for measuring the sedimentation volume, a raw material slurry for cerium-based abrasive and pure water are mixed to prepare a raw slurry so as to have a TREO concentration of 126 g / L. Then, the raw slurry is poured into a 100 mL graduated cylinder up to a 100 mL line, the interface between the precipitate and the liquid after 10 minutes is read, and the volume occupied by the precipitate is defined as the settling volume. In addition, as a measuring cylinder with a nominal capacity of 100 mL, a class A or class B described in JIS R 3505-1994 “Glass volumetric meter” or a cylinder having a precision equal to or higher than that is used. At this time, both a non-plugged type and a plugged type can be used. Moreover, it is preferable to measure the temperature at the time of measuring a sedimentation volume at the constant temperature of 10-50 degreeC, More preferably, it measures at a constant temperature of 15-40 degreeC, More preferably, it is 20-30 degreeC. preferable. And, when adjusting the raw material slurry having a TREO concentration of 126 g / L to B (mL) from the abrasive raw material having a TREO content of A (mass%), the amount C (g) of the abrasive raw material used is: It is calculated based on the following formula.

  The TREO content A of the raw material may be obtained by measuring the TREO of the raw material, but the measurement of TREO requires time and effort. Therefore, the ignition loss D (mass%), which is relatively easier to measure than TREO, may be obtained, and A = 100−D.

  And as for the raw material for abrasives which concerns on this invention, it is preferable that the stationary method apparent specific volume after drying for 12 hours at 120 degreeC is 1.0-3.0 mL / g. Abrasives manufactured from raw materials with an apparent specific volume are likely to have a large average surface roughness (Ra), whereas abrasives manufactured from raw materials with a large apparent specific volume tend to have a low polishing rate. It is. This apparent specific volume is a value obtained by “20.1 stationary method” of “20. Apparent density or apparent specific volume” of JIS K 5101-1991 (pigment test method). A more preferable range of the apparent specific volume is 1.3 to 2.7 mL / g, and a further preferable range is 1.5 to 2.5 mL / g.

  The material for measuring the apparent specific volume after drying is that the raw material for abrasives according to the present invention often contains moisture, and the measured value fluctuates when the apparent specific volume is measured as it is. In particular, when the amount of water is very large, the measurement becomes difficult, and it becomes impossible to use it as a criterion for determining the quality as an abrasive material. Therefore, in order to sufficiently remove the moisture, the film was dried at 120 ° C. for 12 hours.

  In the raw material for abrasives according to the present invention, the cerium oxide content with respect to TREO needs to be 30% by mass or more, but preferably 50% by mass or more. The cerium oxide content in the raw material is directly reflected in the cerium oxide content in the abrasive and affects the polishing rate of the abrasive. When the content of cerium oxide in the raw material is less than 30% by mass, the polishing rate produced is low. In addition, although there is no restriction | limiting in particular about the upper limit of cerium oxide content, A 99.9% or less thing is preferable from a viewpoint of raw material cost.

  Further, the fluorine concentration in the raw material needs to be 0.5% by mass or less with respect to TREO, preferably 0.2% by mass or less, and more preferably 0.1% by mass or less. This is because, as described above, from the viewpoint of environmental problems regarding fluorine and the like, it is naturally preferable that fluorine in the raw material is also reduced when an abrasive without addition of a fluorine component is produced. Further, even when an abrasive is produced by adding a fluorine component, it is easier to control the amount of the fluorine component by using a raw material having a low fluorine concentration.

  In the present invention, “including carbonate radical” clearly indicates that the raw material for an abrasive according to the present invention contains a cerium-based rare earth carbonate. And the raw material for abrasives which concerns on this invention may contain the monooxy carbonate, the hydroxide carbonate, the hydroxide, and the oxide in part.

  The raw material for abrasives according to the present invention preferably has a reduced chlorine concentration. Specifically, it is preferably 0.5% by mass or less (TREO standard), more preferably 0.3% by mass or less, and 0 More preferably, it is 1% by mass or less. This is because if the polishing material contains chlorine, the polishing rate tends to decrease when the polishing material is used.

  The abrasive raw material preferably has a loss on ignition of 20% or more when heated at 1000 ° C. for 1 hour. The loss on ignition is the mass reduction rate when the object is ignited. In the present invention, the loss on ignition is set to 20% by mass or more. If the loss on ignition is less than 20% by mass, the content of carbonate radicals in the raw material is small, and immersion heating and pulverization described later in the abrasive production process is performed. This is because the effect is insufficient when performing. For this reason, the value of ignition loss is preferably large, more preferably 35% by mass or more, and even more preferably 50% by mass or more. The upper limit is not particularly limited, but if the loss on ignition is too high, the transportation cost will increase, so 90 mass% or less is preferred, 70 mass% or less is more preferred, and 60 mass% is preferred. The following is a more preferable range.

  In addition, as a measuring method of ignition loss, after putting the raw material for abrasives into the crucible whose mass was measured in advance and measuring its mass, it was ignited at 1000 ° C. for 1 hour in a furnace and then allowed to cool in a dry atmosphere. Then, after allowing to cool, the mass of the crucible is measured, and the ignition loss can be obtained by following the following formula. If the raw material contains a lot of moisture, suddenly igniting at 1000 ° C may cause the raw material to blow out of the crucible and prevent accurate measurement. After putting the raw material for abrasives and measuring the mass, it is good to heat at 100-150 degreeC, and to ignite after reducing a moisture content.

  Moreover, it is preferable that content of the hexane extract substance measured when the raw material for abrasives which concerns on this invention melt | dissolves in hydrochloric acid is 700 mass ppm or less on the basis of TREO. This hexane extract material does not directly affect the polishing characteristics when the raw material is an abrasive. However, if the amount of hexane extractable material is large, it is difficult to see the interface when measuring the sedimentation volume of the abrasive material. The hexane extractant is preferably 700 ppm by mass or less. More preferably, it is 250 mass ppm or less, and 150 mass ppm or less is still more preferable.

  The hexane extractable substance content is measured by dissolving the raw material for abrasives in hydrochloric acid and in accordance with “24.2 Extraction method” of “24.Hexane extractable substance” in JIS K 0102: 1998 “Factory drainage test method”. Calculated by measuring the amount of hexane extract. That is, when an abrasive material D (g) having a TREO content A (% by mass) is dissolved in hydrochloric acid and the amount of the hexane extractable substance measured for this liquid is E (mg), the abrasive material The TREO standard hexane extraction substance (mass ppm) in the inside is E × 1000 ÷ (D × A ÷ 100).

  In the method for producing an abrasive material according to the present invention, it is necessary that the sedimentation volume when the produced material is slurried is within a predetermined range. According to the inventors, at least one carbonate-based precipitate selected from the group consisting of alkali metal carbonates, alkali metal bicarbonates, ammonium carbonate, ammonium bicarbonate, guanidine carbonate, ammonium carbamate, and urea. By mixing an aqueous solution of an agent and an aqueous solution containing a rare earth compound, a raw material for an abrasive with a controlled sedimentation volume can be produced.

  What is important here is the order of mixing the aqueous solution of the carbonic acid precipitant and the aqueous solution containing the rare earth compound. The raw material for abrasives according to the present invention is required to increase the sedimentation volume to 30 mL (relative to 100 mL of raw material slurry) or more. According to the present inventors, a raw material having an increased sedimentation volume can be produced regardless of the mixing order of these aqueous solutions, but an aqueous solution containing a rare earth compound is added to the stirred aqueous solution of the carbonic acid precipitant. In the case (hereinafter, in order to simplify the explanation, mixing in this order is referred to as a reverse addition method), a raw material having an increased sedimentation volume can be produced regardless of the stirring speed of the aqueous solution of the carbonic acid precipitant.

  That is, the first method for producing the raw material for abrasives according to the present invention comprises alkali metal carbonate, alkali metal bicarbonate, ammonium carbonate, ammonium bicarbonate, guanidine carbonate, ammonium carbamate, and urea. Stirring an aqueous solution of at least one carbonate-based precipitant selected from the group consisting of: a cerium oxide content of at least 30% by mass relative to the total rare earth oxide (TREO), and a fluorine concentration of 0.5% by mass relative to TREO An aqueous solution containing a rare earth compound containing a carbonate radical is mixed to produce a precipitate, and this precipitate is separated and washed.

  On the other hand, when the mixing order reverse to the reverse addition method, that is, when the aqueous solution containing the rare earth compound is stirred and the aqueous solution of the carbonic acid precipitant is added thereto (hereinafter, in order to simplify the explanation, Mixing is referred to as a positive addition method.) In the order), the stirring speed when stirring the rare earth compound aqueous solution is high, specifically, the raw material having an increased sedimentation volume is set to 100 m / min or more. Can be manufactured.

  That is, the second method for producing the abrasive raw material according to the present invention has a cerium oxide content of 30% by mass or more with respect to the total rare earth oxide (TREO) and a fluorine concentration of 0.5% with respect to TREO. % Of a rare earth compound aqueous solution at a peripheral speed of 100 m / min or more, from the group consisting of alkali metal carbonate, alkali metal bicarbonate, ammonium carbonate, ammonium bicarbonate, guanidine carbonate, ammonium carbamate, and urea A step of adding an aqueous solution of at least one selected carbonic acid precipitant to the rare earth compound aqueous solution to form a precipitate, and separating and washing the precipitate.

  Hereinafter, the manufacturing method of the raw material for two abrasives which concerns on this invention is demonstrated. Unless otherwise specified, the following description applies to both the reverse addition method and the normal addition method. In the method according to the present invention, first, two aqueous solutions of an aqueous solution of a carbonic acid precipitant and an aqueous solution containing a rare earth compound are produced.

  The production of aqueous solutions containing rare earth compounds includes, for example, decomposition of cerium-containing rare earth concentrates such as monazite concentrate and bastonite concentrate by sulfuric acid decomposition method and alkali decomposition method, followed by treatment such as fractional precipitation and fractional dissolution. It can be produced by reducing and removing impurities such as uranium, thorium, calcium, barium, iron, phosphorus, etc. and, if necessary, improving the quality of cerium oxide based on TREO by solvent extraction or the like. Further, a rare earth chloride obtained by boiling, cooling and solidifying the hydrochloric acid-based rare earth compound aqueous solution thus obtained may be dissolved in water or dilute hydrochloric acid. Furthermore, instead of using natural cerium-containing rare earth concentrate as a starting material as described above, we will obtain manufactured rare earth compounds such as rare earth chlorides and cerium-based rare earth carbonates and dissolve them with acids such as hydrochloric acid. And it is good also as a solution by adjusting components appropriately. At this time, even if the cerium oxide content is outside the scope of the present invention (less than 30% by mass), it is used in the present invention by increasing the TREO-based cerium oxide content by solvent extraction or the like after dissolution with an acid. be able to.

  Moreover, in order to manufacture the raw material for abrasives having a fluorine concentration of 0.5% by mass or less with respect to TREO, it is natural to use a rare earth compound aqueous solution having a fluorine concentration of 0.5% by mass or less with respect to TREO. However, in the rare earth compound solution containing fluorine, precipitation of rare earth fluoride occurs in the solution, and the rare earth compound solution containing almost no solid content has a fluorine concentration of 0.5% by mass or less with respect to TREO. is there. Therefore, even a rare earth aqueous solution containing a solid content (that is, a rare earth compound solution containing fluorine), a rare earth compound aqueous solution having a fluorine concentration of 0.5% by mass or less with respect to TREO by removing the solid content by filtration or the like. It can be.

  The concentration of the rare earth compound in the rare earth compound aqueous solution is preferably 10 to 250 g / L on the basis of TREO, and more preferably 20 to 200 g / L. When the concentration of the rare earth compound is too low, a large amount of solution is required, which is not preferable from the viewpoint of wastewater treatment. On the other hand, when the concentration of the rare earth compound is too high, the reaction of precipitation generation tends to be non-uniform, and there is a risk of generation of coarse particles.

  As can be understood from the above description, the rare earth compound of the rare earth compound aqueous solution used in the present invention is exemplified by forms such as chloride, nitrate, sulfate, perchlorate, etc., but the rare earth compound used in the present invention is used. The compound aqueous solution is preferably one in which the rare earth compound is present as a chloride. This is because when raw materials are produced from an aqueous chloride solution, there is concern about residual chlorine, but residual chlorine can be easily dealt with by performing sufficient cleaning in a subsequent cleaning step. In this regard, in the case of using an aqueous solution in which a rare earth compound is present as a nitrate, a high-cost wastewater treatment considering recent nitrogen regulations is required for removing residual nitrogen.

  An aqueous solution of a carbonic acid precipitant can be produced by mixing a carbonic acid precipitant with water (pure water). The carbonate-based precipitant contains at least one of alkali metal carbonate, alkali metal bicarbonate, ammonium carbonate, ammonium bicarbonate, guanidine carbonate, ammonium carbamate, and urea. Sodium, potassium, and lithium are suitable as the alkali metal of the alkali metal carbonate and alkali metal hydrogencarbonate. As the carbonate-based precipitating agent, those containing no alkali metal are preferable in that the alkali metal is not mixed into the precipitate, and among them, ammonium hydrogen carbonate is preferable. The concentration of the carbonic acid precipitating agent is preferably 0.2 to 1.0 mol / L. This is because if the amount is less than 0.2 mol / L, the amount of drainage increases, and if it exceeds 1.0 mol / L, the reaction may become non-uniform. And the usage-amount of the aqueous solution of a carbonic acid type precipitation agent is based on the usage-amount of rare earth compound aqueous solution (it relates to the production amount of the target raw material). The amount of the carbonate-based precipitant is 0.95 to 2.5 times (preferably 1.0 to 2.0 times, more preferably) the stoichiometric amount with respect to the rare earth element and the excess acid in the rare earth compound aqueous solution. Is preferably 1.1 to 1.5 times), and the amount of the aqueous solution used is preferably determined in consideration of the concentration of the carbonate-based precipitant based on this amount. If the amount is less than the lower limit, precipitation of rare earth elements does not occur sufficiently and the yield decreases. The amount of excess acid in the rare earth compound aqueous solution can be determined by neutralization titration using, for example, bromocresol green-methyl red solution as an indicator. However, when the pH of the rare earth compound aqueous solution is 1 or more (especially 2 or more), it can be said that the amount of excess acid is small, so there is little influence even if ignored.

  And precipitation is produced | generated by mixing the aqueous solution of the manufactured carbonate type precipitation agent, and rare earth compound aqueous solution. Here, the object of stirring and the order of mixing differ between the reverse addition method and the normal addition method. In the reverse addition method, an aqueous solution of a carbonic acid precipitant is stirred and a rare earth compound aqueous solution is added thereto, but the stirring speed at this time is not limited.

  On the other hand, in the positive addition method, an aqueous carbonate precipitant solution is added while stirring the rare earth compound aqueous solution, and the stirring speed at this time is the peripheral speed (the speed at the part farthest from the stirring shaft of the stirring blade). It is necessary to set it as 100 m / min or more. This is because there is a high possibility that a raw material for an abrasive having a sedimentation volume of less than 30 mL will be produced even if stirring is performed at a stirring speed below this. The stirring speed in the positive addition method is more preferably 125 m / min or more, and particularly preferably 150 m / min or more. Although there is no restriction | limiting in the upper limit of stirring speed, From a viewpoint of the cost of a stirring apparatus, 4000 m / min or less, Preferably it is 3000 m / min or less, More preferably, it is 2000 m / min or less.

  The addition time of the rare earth compound aqueous solution or the carbonic acid precipitant aqueous solution is preferably 5 to 1200 minutes, more preferably 10 to 600 minutes, and still more preferably 20 to 300 minutes. If added too quickly, the resulting precipitate becomes fine particles, the polishing speed of the produced abrasive is reduced, the produced precipitate is non-uniform, and the polishing accuracy of the produced abrasive is slightly reduced. On the other hand, if it is added too slowly, a coarse precipitate is formed, and the polishing accuracy of the produced abrasive is lowered. Further, at the time of mixing, there is no particular need to warm the solution, but it may be warmed. In this case, the liquid temperature is preferably 60 ° C. or less, particularly preferably 40 ° C. or less. When the temperature of the solution becomes high, the precipitate becomes coarse, and the polishing accuracy of the manufactured abrasive is lowered.

  The precipitate formed by mixing the aqueous carbonate precipitant solution and the rare earth compound aqueous solution is subjected to solid-liquid separation and washing, whereby the raw material for the abrasive according to the present invention can be obtained. The abrasive raw material after washing may be appropriately dried.

  In addition, as mentioned above, it is preferable that the abrasive according to the present invention has a hexane extract substance content of 700 mass ppm or less based on TREO as measured when dissolved in hydrochloric acid. The hexane extract material is derived from an organic solvent used for solvent extraction, which is generally performed in the manufacturing process of the raw material for abrasives. Thus, as a first method for reducing the hexane extract material, there is a method in which a rare earth compound aqueous solution containing the hexane extract material is allowed to stand and the hexane extract material in the aqueous solution is separated and removed. As a second method, there is a method in which an aqueous rare earth compound solution containing a hexane extract substance is brought into contact with an oil adsorbent such as polypropylene fiber, plant fiber, activated carbon, etc., and the hexane extract substance is adsorbed and removed. It is preferable that at least one of these steps for removing the hexane extractant is performed. However, by performing the second method after the first method is performed, it becomes more effective.

  Further, in order to reduce the hexane extract material, it is more efficient that the pH is lower in both the first and second methods. Specifically, the pH of the rare earth compound aqueous solution is preferably 3.0 or less, more preferably 2.0 or less, and even more preferably 1.0 or less. However, if the pH is too low, it is preferable from the viewpoint of removing the hexane extract material, but more precipitant is required. Therefore, the lower limit of the pH of the rare earth compound aqueous solution to be subjected to the hexane extract substance reduction treatment is preferably 0.0 or more, and more preferably 0.2 or more.

  In order to produce a cerium-based abrasive with the raw material for an abrasive according to the present invention, a conventional method can be basically applied. That is, the abrasive material can be produced by pulverizing the raw material for the abrasive material and then roasting and appropriately pulverizing and classifying it.

  Here, as a grinding | pulverization process of the raw material for abrasives performed before a roasting process, it is generally performed by a grinding | pulverization apparatus, especially a wet grinding apparatus. In the present invention, pulverization by a pulverizer is also useful. However, as a more effective grinding method, an aqueous solution containing at least one compound selected from the group consisting of ammonia, ammonium carbonate, ammonium hydrogen carbonate, guanidine carbonate, ammonium carbamate, and urea, or polishing with water The raw material for materials may be mixed, and this may be heated at 60-100 degreeC, and the raw material for abrasives may be grind | pulverized (Hereinafter, such a grinding method is called immersion heating grinding). By performing this immersion heating and pulverization, the manufactured abrasive can form a highly accurate polished surface with few abrasive scratches. The timing of this immersion heating pulverization is not particularly limited as long as it is before the roasting step. However, the immersion heating pulverization does not prevent the pulverization by the pulverizer. Therefore, both pulverization methods may be appropriately combined.

  As described above, by using the cerium-based abrasive raw material according to the present invention, the polishing speed is equal to or higher than that of the conventional abrasive produced using the cerium-based abrasive raw material. A cerium-based abrasive capable of forming a polished surface can be produced. Since the raw material for abrasives according to the present invention hardly contains fluorine or the like as its original property, it can cope with environmental problems and recycling of abrasives. The cerium-based abrasive raw material according to the present invention is particularly useful in the case of producing an abrasive without adding a fluorine component, but the fluorine component is added while adjusting the concentration of the fluorine component. It can also be used for manufacturing.

  Hereinafter, preferred embodiments of the present invention will be described. In the present embodiment, in a method for producing a raw material for abrasives by mixing a carbonate-based precipitant aqueous solution and a rare-earth compound aqueous solution, a plurality of rare-earth compound aqueous solutions are produced by different starting materials and steps, and this is used as a carbonate-based precipitant. A plurality of raw materials for abrasives were produced by adding and mixing with an aqueous solution. And the cerium type abrasive material was manufactured from these, and those polishing characteristics were evaluated.

A: Production of Rare Earth Compound Aqueous Solution A plurality of rare earth compound aqueous solutions were produced by the following two steps.
Manufacturing process 1
In this production process, an aqueous rare earth compound solution is produced using rare earth chloride as a starting material. The raw material for abrasives obtained from the rare earth compound aqueous solution produced by this production process corresponds to Examples 1 to 30, 36 to 44, and Comparative Examples 1, 2, and 4 described later. An outline of this manufacturing process is shown in FIG.

  A rare earth chloride (46% by mass of TREO) is dissolved in 0.3 mol / L hydrochloric acid to obtain a solution having a TREO concentration of 150 g / L, and this is subjected to solvent extraction. Solvent extraction was performed in 30 stages (10 counter-current extraction stages, 20 counter-current counter-extraction stages) mixer-settler-settler section effective capacity: 200 L / stage). The organic solvent enters the first stage of the extraction unit at a capacity of 6 L / min, exits from the tenth stage, enters the first stage of the back extraction unit as it is, and exits from the 20th stage. In the extraction part, a solution is put into the extraction part at 1 L / min in the extraction part in the extraction part, and a 2 mol / L sodium hydroxide aqueous solution is added to each of the extraction parts in the first, third, fifth, and seventh stages at 0.35 L / min. The amount is added and comes out from the first stage of the extraction section. In the back extraction unit, 5.2 mol / L hydrochloric acid was added at 1 L / min from the 20th stage of the back extraction unit, 0.56 L / min was extracted from the 11th stage, and the rest was extracted from the 1st stage of the back extraction unit. Sodium hydroxide is added to extract almost all of the rare earth elements in the solution into an organic solvent. The organic solvent is a mixture of an extractant (PC-88A (manufactured by Daihachi Chemical Industry Co., Ltd.)) and a diluent (IP solvent (manufactured by Idemitsu Petrochemical Co., Ltd.)) at a volume ratio of 1: 2. is there.

  Next, the pH of the back extract (TREO concentration: 291 g / L) extracted from the first stage of the back extraction part of the solvent extraction step was adjusted with hydrochloric acid to pH = 0.9, which was left to stand for 24 hours. The oil and water were separated (however, in Example 22, the standing time was 3 hours, and in Examples 21 and 24, oil and water were not separated).

  And the adsorbent process was performed by passing the back extraction liquid after the said process through the column filled with the polypropylene fiber (however, in Examples 21-23, the adsorbent process was not performed).

  About the back extraction liquid (rare earth compound aqueous solution) which performed the above process, the density | concentration was adjusted suitably with a pure water, and it was set as the rare earth compound aqueous solution of 5-270 g / L of TREO density | concentration. In the above steps, the composition in TREO contained in the rare earth chloride (solution) before treatment and the composition in TREO contained in the back extraction solution (rare earth compound aqueous solution) after solvent extraction are as follows. It was. Moreover, the rare earth element amount per 1 kg of TREO of the manufactured rare earth compound aqueous solution was 5.92 mol.

Manufacturing process 2
In this manufacturing process, a rare earth compound aqueous solution is prepared using cerium carbonate (TREO 45 mass%, CeO ₂ /TREO>99.9 mass%: a raw material for an abrasive material comprising this cerium carbonate is used as Comparative Example 3). Manufactured. The raw material for abrasives obtained from the rare earth compound aqueous solution produced by this production process corresponds to Examples 31 to 35 described later. An outline of this manufacturing process is shown in FIG.

  The cerium carbonate was dissolved in 0.2 mol / L hydrochloric acid and filtered to obtain a solution having a TREO concentration of 180 g / L. Then, the pH of this solution was adjusted with hydrochloric acid to pH = 0.9, and this solution was allowed to stand for 24 hours to separate oil and water.

Then, the treated solution was passed through a column filled with polypropylene fibers to carry out adsorbent treatment. The solution after the adsorbent treatment was appropriately adjusted with pure water to obtain a rare earth compound aqueous solution having a TREO concentration of 50 g / L. The rare earth compound aqueous solution had a cerium oxide concentration (CeO ₂ / TREO) of 99.9% by mass or more. Further, the amount of rare earth element per kg of TREO in the produced rare earth compound aqueous solution was 5.81 mol (calculated assuming CeO ₂ / TREO as 100 mass%).

B: Production of Aqueous Carbonic Precipitant Solution An aqueous carbonate precipitant solution was produced by dissolving a carbonate precipitant (ammonium hydrogen carbonate or sodium carbonate) in water. The dissolution amount of the carbonate-based precipitant is the total amount of the stoichiometric amount with respect to the rare earth element contained in each rare earth compound aqueous solution and the stoichiometric amount necessary for neutralizing excess acid determined by neutralization titration. 1.2 times the amount. In addition, since almost all of the rare earth elements in the rare earth compound aqueous solutions of the respective examples are trivalent, calculation was performed with trivalence.

C: Mixing a carbonate-based precipitant aqueous solution and a carbonate-based precipitant aqueous solution, and mixing a rare earth compound solution and a carbonate-based precipitant aqueous solution to form a precipitate, which was washed to produce an abrasive raw material.

  In Examples 1 to 40, the reverse addition method, that is, 30 kg of the rare earth compound aqueous solution was added while stirring the aqueous solution of the carbonic acid precipitation agent. As the addition time at this time, a plurality of addition times of 3 to 1200 minutes were adopted, and a plurality of speeds of 50 to 175 m / min were set as the stirring speed (peripheral speed) of the aqueous solution. Furthermore, about the solution heating at the time of addition, it mixed by both the case where it performs (30-70 degreeC) and the case where it does not perform. The solution after addition of the rare earth compound aqueous solution was stirred for 30 minutes until the start of the next filtration step.

  On the other hand, in Examples 41 to 44 and Comparative Examples 1, 2, and 4, precipitates were generated by the positive addition method, that is, the method of adding an aqueous solution of a carbonic acid precipitant while stirring the rare earth compound aqueous solution. Even in this case, a plurality of speeds of 50 to 175 m / min were set as the stirring speed.

  In the above examples, the stirring speed of the aqueous carbonic acid precipitant solution or the rare earth compound aqueous solution was 75 m / min in both cases of the reverse addition method and the normal addition method, unless otherwise specified.

D: Solid-liquid separation, washing The solution was vacuum filtered in order to separate the precipitate formed by stirring the aqueous solution of the carbonated precipitant and the rare earth compound aqueous solution. And the precipitate separated by filtration was wash | cleaned and it was set as the raw material for cerium type abrasives. This washing was performed with 100 L / times pure water, and was washed 0 to 5 times (only Comparative Example 7 was not washed (0 times)).

For manufactured cerium-raw material for the above process, sedimentation volume, hexane extract content, TREO concentration, the fluorine concentration, chlorine concentration, loss on ignition was measured average particle diameter (D ₅₀ particle size). In the measurement of these characteristics, the measurement of the sedimentation volume, the apparent specific volume of the stationary method, the hexane extract substance content, and the loss on ignition was in accordance with the measurement method described above.

  The fluorine concentration was measured by melting the abrasive with alkali and extracting it with hot water, and measuring it by the fluoride ion electrode method. The chlorine concentration was measured by the Volhard titration method after the abrasive was dissolved in nitric acid. In addition, TREO serving as a reference was measured by a gravimetric method by dissolving an abrasive in an acid and adding oxalic acid to the solution to form a precipitate. The precipitate was fired.

Measurement of the average particle diameter (D ₅₀ particle size) is a laser diffraction scattering method particle size distribution measuring apparatus (manufactured by HORIBA, Ltd.: LA-920) using by measuring the particle size distribution, the volume-based This was carried out by determining the 50 mass% diameter in the integrated fraction.

  Tables 2 to 7 show various characteristics of various abrasive raw materials produced in this embodiment.

  Next, a cerium-based abrasive was produced using the plurality of produced cerium-based abrasive materials. In the abrasive production process, first, the produced raw material for abrasive was immersed and pulverized. Immersion heating pulverization is performed in a tank with a capacity of 350 L, mixing 30 kg of abrasive raw material TREO with 150 L of pure water, blowing in steam with stirring and maintaining this temperature for 3 hours after reaching 90 ° C., and then allowing to cool. It went by.

And the slurry after immersion heating grinding | pulverization was filtered, the raw material for abrasives was dried at 150 degreeC for 48 hours, the dry grinding | pulverization was performed with the atomizer, and the baking process was carried out. The roasting conditions were a heating temperature of 980 ° C. (CeO ₂ /TREO>99.9% by mass) and 1050 ° C. (CeO ₂ / TREO 60% by mass), and a time of 24 hours.

  After the roasting treatment, the roasted product was made into a 64 L slurry with pure water and then wet pulverized. The wet pulverization was performed for 5 passes in a bead mill using zirconia balls having a diameter of 1.0 mm. And after filtering a slurry, it dried at 150 degreeC for 48 hours, and it was set as the cerium type abrasive | polishing material by performing dry grinding | pulverization with an atomizer.

Evaluation of Characteristics of Abrasives And various cerium-based abrasives produced were measured for average particle diameter and BET surface area, and were subjected to a polishing test to evaluate their polishing characteristics (polishing speed, polishing accuracy).

The measurement of the specific surface area of the BET method is based on “(3.5) One-point method of 6.2 flow method” of JIS R 1626-1996 (Method of measuring specific surface area of fine ceramic powder by gas adsorption BET method). Measurements were made. At that time, a mixed gas of helium as a carrier gas and nitrogen as an adsorbate gas was used. Also, measurement of the average particle diameter (D ₅₀ particle size) were the same as the measuring method of the raw material.

For the polishing test, a polishing tester (HSP-2I type, manufactured by Taito Seiki Co., Ltd.) was prepared. This polishing tester polishes the polishing target surface with a polishing pad while supplying a slurry-like polishing material to the polishing target surface. In the polishing test, a polishing material and pure water were mixed to prepare 20 L of a slurry-like polishing material of TREO 100 g / L. In the polishing test, a slurry-like abrasive was supplied at a rate of 5 liters / minute, and the abrasive was recycled. The polishing object was a glass for a flat panel having a diameter of 65 mm. A polishing pad made of polyurethane was used. The polishing pad pressure against the polishing surface was 9.8 kPa (100 g / cm ² ), the rotation speed of the polishing tester was set at 100 rpm, and polishing was performed for 30 minutes.

  Then, the evaluation of the polishing characteristics was performed by first measuring the glass weight before and after polishing to determine the amount of glass weight reduction by polishing, and determining the polishing value based on this value. In this polishing test, the polishing rate was evaluated using this polishing value. Here, the polishing value when polishing was performed using the sample obtained in Example 1 was used as the reference (100).

  Then, the polished surface of the glass obtained by polishing was washed with pure water and dried in a dust-free state, and then the polishing accuracy was evaluated. This evaluation was performed by measuring the surface roughness of the polished surface of the glass after polishing with an atomic force microscope (AFM) and evaluating Ra (average surface roughness).

  Tables 8 to 13 show the results of the physical properties and polishing characteristics of the various abrasives produced.

  When comparison is made on the basis of the physical property values (Tables 2 to 7) of the raw materials for abrasives produced by the above various production processes and the abrasive properties (Tables 8 to 13) of the abrasives produced by them. Considered as follows.

Evaluation 1: Evaluation by sedimentation volume Tables 8 to 11 show comparison results of characteristics of abrasives produced using raw materials for abrasives having different sedimentation volumes produced while changing production conditions. The settling volume of the raw material for abrasives varies depending on the production conditions (concentration of rare earth compound aqueous solution, addition time, number of times the precipitate is washed) (this point will be described later). In either case, the settling volume is 30 mL. Abrasives produced from less than the raw material for abrasives have a high polishing speed but a large surface roughness and poor polishing accuracy (scratches were confirmed). Therefore, it can be seen that the settling volume of the raw material for the abrasive is required to be 30 mL or more. On the other hand, an abrasive produced from a raw material for an abrasive having a sedimentation volume exceeding 90 mL has a low polishing rate. Therefore, considering the balance between the polishing speed and the polishing accuracy, the sedimentation volume is preferably 30 to 90 mL, more preferably 30 to 70 mL, and even more preferably 40 to 60 mL.

  Table 14 shows the results of a complementary study on the influence of temperature when measuring the sedimentation volume of the abrasive raw material. This examination investigated the measured value when the temperature at the time of measurement was changed when measuring the sedimentation volume of the raw material for abrasives manufactured in Example 6.

  As can be seen from Table 14, in the measurement temperature range of 10 to 50 ° C., there is no significant difference in the measured value of the sedimentation volume. Therefore, it can be said that the sedimentation volume is preferably measured in this temperature range. In addition, all the values of the sedimentation volume shown by this embodiment have shown what was measured at 25 degreeC.

Evaluation 2: Evaluation by standing method apparent specific volume Further , Tables 8 to 11 also show values of the standing method apparent specific volume (indicated by FV in the table). The apparent specific volume of the abrasive raw material varies depending on the production conditions as well as the sedimentation volume, but the value of the static specific volume is 1.0 to 3.0 mL / g (implementation) Examples 3 to 13) are particularly excellent in the balance between the polishing speed and the polishing accuracy. More preferably, it is 1.3 to 2.7 mL / g, and even more preferably 1.5 to 2.5 mL / g.

Evaluation 3: Evaluation by concentration of hexane extractant Table 9 shows the relationship between the concentration of the hexane extractant of the raw material for the abrasive and the polishing characteristics of the abrasive. From this table, it can be said that the hexane extractant does not significantly impair the polishing characteristics of the abrasive, but the increase in the hexane extractant affects the visibility of the interface when measuring the sediment volume of the abrasive material. Giving. Therefore, it is preferable that the concentration of the hexane extractant be as small as possible.

Evaluation 4: Evaluation by Chlorine Concentration Table 10 shows the relationship between the chlorine concentration of the raw material for the abrasive and the polishing characteristics of the abrasive. From this table, it can be seen that chlorine in the raw material affects both the polishing speed and the polishing accuracy when it is used as an abrasive. In order to produce a more suitable abrasive, the chlorine concentration of the abrasive raw material is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and 0.1% by mass or less. Is more preferable.

Evaluation 5: Evaluation of raw material production conditions I (addition time and order of addition of rare earth compound aqueous solution)
Table 2 shows the relationship between the addition time when adding the rare earth compound aqueous solution to the carbonate-based precipitant aqueous solution and the sedimentation volume of the abrasive raw material during the conditions of the manufacturing process of the raw material for abrasive. As can be seen from this result, the sedimentation volume tends to decrease as the addition time of the rare earth compound aqueous solution increases, but it can be seen that the sedimentation volume falls within the preferred range even in a relatively wide range. However, the addition time is preferably 5 to 1200 minutes, more preferably 10 to 600 minutes, and still more preferably 20 to 300 minutes in order to set the sedimentation volume of the raw material within the above-described preferred range.

  Further, as shown in Table 6, regarding the influence of the stirring speed of the carbonic acid precipitant solution when the precipitate is produced by the reverse addition method, the settling volume is large even if the stirring speed of the carbonic acid precipitant solution is set in a wide range. It can be seen that there is no fluctuation.

  On the other hand, Comparative Examples 1 and 2 in Table 2 were precipitated by the positive addition method, but the raw material for abrasives of this Comparative Example had a sedimentation volume of less than 30. Regarding this result, Table 7 shows the result when the precipitate was generated by changing the stirring speed of the rare earth compound aqueous solution by the positive addition method. From this result, it can be seen that when the positive addition method is applied, a raw material for an abrasive having a sedimentation volume of 30 mL or more can be produced by setting the stirring speed to an appropriate range (100 m / min or more).

Evaluation 6: Evaluation of raw material production conditions II (presence or absence of heating during mixing of aqueous solution)
Table 3 shows the physical properties of the raw material for the abrasive depending on the presence or absence of heating and the temperature when mixing the aqueous carbonate-based precipitant solution and the rare earth compound aqueous solution. From this table, it can be seen that heating at the time of mixing the aqueous solution is not essential for controlling the sedimentation volume of the abrasive material. Even when heating, if the liquid temperature exceeds 60 ° C., the sedimentation volume tends to be low. Therefore, the liquid temperature during mixing is preferably 60 ° C. or less, and particularly preferably 40 ° C. or less.

Evaluation 7: Evaluation of raw material production conditions III (concentration of rare earth compound aqueous solution)
Table 3 shows the relationship between the rare earth compound concentration (TREO concentration) and the sedimentation volume of the abrasive raw material when adding the rare earth compound aqueous solution to the carbonate-based precipitant during the conditions of the manufacturing process of the abrasive raw material. . As can be seen from this result, as the concentration of the rare earth compound aqueous solution increases, the sedimentation volume also tends to increase, but it is understood that a material for an abrasive material having a suitable sedimentation volume can be obtained in a wide concentration range. However, in order to obtain a raw material for an abrasive with a more preferable sedimentation volume, the concentration of the rare earth compound aqueous solution is preferably 10 to 250 g / L, more preferably 20 to 200 g / L on the basis of TREO.

Evaluation 8: Evaluation of raw material manufacturing conditions IV (adsorption treatment of rare earth compound aqueous solution)
Table 3 also shows differences in the physical properties of the raw materials for the abrasives depending on whether or not the remaining liquid after solvent extraction in the manufacturing process of the rare earth compound aqueous solution is subjected to a stationary treatment and an adsorption treatment. As can be seen from this result, the stationary treatment and the adsorption treatment have an effect of reducing the concentration of the hexane extract substance in the raw material for the abrasive. As described above, the hexane extract material does not greatly affect the characteristics of the abrasive material, but affects the visibility of the interface when measuring the sedimentation volume of the abrasive material. Therefore, it can be said that it is preferable to perform at least one of a stationary treatment and an adsorption treatment.

Evaluation 9: Evaluation of raw material production conditions V (effect of washing the precipitate)
Table 4 shows the presence / absence of washing and the number of precipitates produced by mixing a carbonate-based precipitant aqueous solution and a rare earth compound aqueous solution, and the physical properties of the abrasive material. As can be seen from this table, the chlorine concentration of the abrasive raw material is reduced by washing, and the concentration decreases as the number of washings increases. The chlorine concentration in the raw material and the polishing characteristics of the abrasive are as described above. In the manufacturing process of the raw material for abrasives, it can be said that it is preferable to sufficiently wash the precipitate.

Evaluation 10: Evaluation of raw material production conditions VI (type of carbonate-based precipitant)
Table 4 shows the difference depending on the kind of the precipitating agent in the aqueous carbonate precipitant mixed with the rare earth compound aqueous solution. From this table, the precipitation volume of the raw material for the abrasive is within the preferred range even if any carbonate type precipitation agent such as ammonium bicarbonate or sodium carbonate is used. That is, there is no great difference depending on the kind of the precipitant.

Evaluation 11: Evaluation of raw material production conditions VI (type of starting material)
In this embodiment, a rare earth compound solution is produced using two starting materials of rare earth chloride (Examples 1 to 30) and Chinese cerium carbonate (Examples 31 to 35) as starting materials, and the raw materials for abrasives are used. Is manufactured and used as an abrasive. For comparison, an abrasive is produced using cerium carbonate from China as a raw material (Comparative Example 3). When examining the difference between these starting materials, even the purified cerium carbonate as in Comparative Example 3 is inferior in sedimentation volume and polishing characteristics when used as an abrasive compared to each Example. I understand. Accordingly, it can be seen that even such cerium carbonate with good purity is once effective as an aqueous rare earth compound solution as in this example. On the other hand, as can be seen by comparing Examples 1-30 and Examples 31-35. In the case where the raw material is produced via the rare earth compound aqueous solution as in the examples, it can be said that there is no difference in characteristics due to the difference in the starting raw materials.

  By the way, in this embodiment, the comparative examples 1 and 2 differ from an Example in the manufacturing conditions (addition order of rare earth compound aqueous solution). And as a result, the manufactured raw material for abrasives has a sedimentation volume exceeding a suitable range. Therefore, for such an abrasive raw material, it is possible to produce a suitable abrasive raw material by making it a rare earth compound aqueous solution again (that is, even if it is a non-standard abrasive raw material). It can be reprocessed as a starting material to make a suitable abrasive material). As an example, the following examples are shown.

Examples 45 and 46
The raw materials for abrasives produced in Comparative Examples 1 and 2 were dissolved in hydrochloric acid, and the filtrate obtained by filtering this was diluted with pure water and adjusted to pH 0.9 with hydrochloric acid to obtain a rare earth compound aqueous solution. The TREO concentration at this time was 50 g / L.

  Next, this rare earth compound aqueous solution was added to the stirring carbonic acid precipitant aqueous solution (ammonium hydrogen carbonate aqueous solution) in an addition time of 60 minutes. The produced precipitate was filtered off and washed 5 times with 100 L / times of pure water to obtain an abrasive material. The other conditions such as the concentration of the carbonic acid precipitant aqueous solution were the same as described above.

  And the cerium-type abrasive | polishing material was manufactured in the process similar to the above from the raw material for abrasives manufactured at the above process, and the grinding | polishing characteristic was evaluated. Table 15 shows the results.

  As can be seen from this result, even if the raw material for the abrasive exceeds the appropriate range, it can be made into an aqueous solution of a rare earth compound and an appropriate raw material can be used for the raw material for the abrasive. It can be confirmed that the polishing characteristics can be improved.

The figure which illustrates schematically manufacturing process 1 and 2 of the rare earth compound containing aqueous solution in this embodiment.

Claims (12)

A cerium-based abrasive raw material having a cerium oxide content of 30% by mass or more with respect to total rare earth oxide (TREO) and a fluorine concentration of 0.5% by mass or less with respect to TREO and containing a rare earth compound containing a carbonate radical,
A cerium-based abrasive raw material having a sedimentation volume of 30 mL or more with respect to 100 mL of the raw material slurry when the raw material slurry mixed with pure water so as to have a TREO concentration of 126 g / L is allowed to stand for 10 minutes. The raw material for a cerium-based abrasive according to claim 1, wherein the apparent specific volume (according to JIS K 5101-1991) after drying at 120 ° C for 12 hours is 1.0 to 3.0 mL / g. The cerium-based abrasive raw material according to claim 1 or 2, wherein the content of the hexane-extracted substance measured when dissolved in hydrochloric acid is 700 ppm by mass or less based on TREO. A method for producing a cerium-based abrasive material,
Stirring an aqueous solution of at least one carbonate-based precipitant selected from the group consisting of alkali metal carbonate, alkali metal bicarbonate, ammonium carbonate, ammonium bicarbonate, guanidine carbonate, ammonium carbamate, and urea;
A rare earth compound aqueous solution having a cerium oxide content of 30% by mass or more with respect to total rare earth oxide (TREO) and a fluorine concentration of 0.5% by mass or less with respect to TREO is added to the aqueous solution of the carbonic acid precipitant. Produces
A method for producing a raw material for a cerium-based abrasive, comprising a step of separating and washing the precipitate. A method for producing a cerium-based abrasive material,
A rare earth compound aqueous solution having a cerium oxide content of 30% by mass or more based on total rare earth oxide (TREO) and a fluorine concentration of 0.5% by mass or less based on TREO at a peripheral speed of 100 m / min or more;
An aqueous solution of at least one carbonate-based precipitant selected from the group consisting of alkali metal carbonates, alkali metal bicarbonates, ammonium carbonate, ammonium bicarbonate, guanidine carbonate, ammonium carbamate, and urea; Add to aqueous solution to form precipitate,
A method for producing a raw material for a cerium-based abrasive, comprising a step of separating and washing the precipitate. 6. The cerium-based abrasive raw material according to claim 4, wherein the rare earth compound aqueous solution is obtained by reducing at least one of the following treatments (a) and (b) to reduce the hexane extract material. Production method.
(A) A treatment in which a rare earth compound aqueous solution is allowed to stand to separate and remove the hexane extract material in the rare earth compound aqueous solution.
(B) A process of adsorbing and removing the hexane extract material by bringing a rare earth compound aqueous solution and an oil adsorbent into contact with each other. The raw material for cerium-type abrasives manufactured by the method of any one of Claims 4-6. The raw material for a cerium-based abrasive according to claim 1 or 2, produced by the method according to claim 4 or 5. The raw material for a cerium-based abrasive according to claim 3, which is produced by the method according to claim 6. A cerium-based abrasive produced from the cerium-based abrasive raw material according to any one of claims 1 to 3, or any one of claims 7 to 9. The manufacturing method of the cerium type abrasive | polishing material which uses the raw material for cerium type | system | group abrasive materials of any one of Claims 1-3 or any one of Claims 7-9. A method for producing a cerium-based abrasive using the raw material for a cerium-based abrasive according to any one of claims 1 to 3, or any one of claims 7 to 9.
Including a roasting step, a grinding step of the raw material for abrasives performed before the roasting step,
In the pulverization step, an aqueous solution containing at least one compound selected from the group consisting of ammonia, ammonium carbonate, ammonium hydrogen carbonate, guanidine carbonate, ammonium carbamate, and urea, or the raw material for abrasives in water is used. A method for producing a cerium-based abrasive, which is immersed and heated at 60 to 100 ° C. to grind the raw material for the abrasive.

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