US2195724A - Process of ore concentration - Google Patents

Description

Patented Apr. 2,1940

UNITED STATES 1 ATENT omen crnoccss or one conccnm'non Antoine M. Gaudin, Butte, Mont, and John Dixon Vincent No Drawing.

8 Claims.

The present invention relates to an improved process of concentrating orescontaining at least one mineral or each or the following three classes;

I. This first class consists of non-sulfide nonsilicon bearing minerals, among which may be mentioned. the carbonates, sulfates, phosphates, oxides, nitrates, chlorides, etc., of various metals.

, These minerals may be of either metalliferous or non-metalliferous character; Among. the metal atoms which they may contain are thus included sodium, potassium, calcium, barium, magnesium, manganese, iron, copper, lead, zinc, silver, gold, platinum, etc.

E. This second class consists of metalliferous sulfide minerals, among which maybe mentioned the sulfides of lead, zinc, copper, iron, nickel, silver, etc.

m. This third class consists of silicon-bearing gangue minerals, among which may be mentioned quartz, micas, garnets, feldspars, etc.

The process of the present invention "is of the type effecting concentration by gas-bubble attachment to some of the minerals of the ore,

which in this state are separated from the waterwetted minerals. There are two general classes of agents known in the art to promote this type of concentration, namely, agents of the negativeion type and agents of the positive-ion type.

For a clear understanding of this invention, these two classes of'agents will be discussed briefly.

Negative-ion agents are fundamentally characterized by the presence or an efiective anion and an ineffective cation, while positive-ion agents are fundamentally characterized by the presence of an effective cation and an inefiective anion. Thecation of negative-ion agents may thus be replaceable hydrogen (H or a metallic ion such as Na K etc. On the other hand, the anion of positive-ion agents may be a halogen (61-, Br, I, F-), or an acid radical such as 804-: PG4 CHaCOO", etc. These positive and negative ions are all innocuous ions utterly incapable in themselves of effecting an attach-- agent to the selected minerals and a water I repellent hydrocarbon group causing adherence of the gas bubbles to the agent are caused to be included in the anion of negative-ion agents and in the cation of positive-ion agents. Typical examples of negative-ion agents are fatty acid soaps, xanthates, alkyl tri-thio carbonates, alkyl sulphates and sulphonates, substituted thicureas, di-thio phosphates, etc., which owe their efiectiveness to the anion oftheir molecules, while typical examples of positive-ion agents are Whittier, Cali].

Application August 24, 1938, Serial No. 226,432

1 salts of alkyl amines with halogen and other acids, alkyl and aryl pyridinium salts of halogen and other'acids, alkyl and aryl quinolinium salts of halogen and other acids, alkyl and aryl sulphonium salts of halogen and other acids, alkyl and aryl phosphonium salts of halogen and other acids, etc., which owe their effectiveness to the cation of their molecules.

The process oi the present invention is one according to which the aforementioned complex ores containing three different classes of minerals are treated with agents .of the positive-ion type with the view to eflecting gas-bubble attachment on the minerals of each of the two classes 11 and III. Therefore, these minerals are collectively separated from the minerals of class I, by which operation the latter minerals are to a large extent recovered in concentrated form in the water-wetted residue. Thereafter, if the economic worth of the product separated by gas-bubble attachment warrants further treatment, it may be treated in'the usual manner by agents of the negative-ion type to recover the minerals of class II.

In certain instances, use can also advantageously be made of agents of the negative-ion type prior to the treatment with agents of the positive-ion type. For example, the'ore tonndergo treatment 'may first be processed with agents of the negative-ion type to yield a prodnot containing some of the minerals of class III in admixture with the larger part of the miner'als of eachv of classes I and Ii. By subsequent treatment of this product with agents of the positive-ion type, the minerals of class I can then most readily be recoveredby a separating action on the minerals of each of the classes 11 and m.

The process of the present invention may thus include each of the following principal steps carried out inthe sequence indicated:

(A) Separation of hon-sulfide non-siliconbearing minerals and metalliferous sulfide min erals from silicon-bearing gangue minerals by negative-ion agents (B) Separation of metalliferous' sulfide minerals and silicon-bearing gangue minerals from non-sulfide non-silicon-bearing minerals by positive-ion agents; and

(0) Separation of metalliferous sulfide minerals from silicon-bearing gangue minerals by negative-ion agents.

In practice, of course, these principal steps may actually comprise a plurality of separating operations. Step C may thus constitute a series of operations in which the various SiL- fide minerals are selectively separated from each other, or in which these minerals are first collectively separated and thereafter selectively separated. Also, any of the three steps mentioned d0 may include various operations of retreatment carried out with the usual view to obtaining higher-grade concentrates or cleaner tailings.

It should also be noted that step B 'is the only one of the three principal steps mentioned which actually needs to be carried out in all cases. The present invention is one broadly residing in a collective separation of the minerals of each of the two classes II and 111 from the minerals of class I by positive-ion agent treatment. The process of t e present invention is thus in no way limited 0 any steps which may be carried out either before or after this collective separa-' tion in accordance with step B. I

In accordance with the invention, the posi tive-ion agent treatment of step Bis carried out with the additional use of cyanide, which we have found to materially improve the collective separation possible by such'treatment. We do not know the mechanism that is effective in this use of cyanide'in our process, but we have observed as one effect an excellent dispersion of slimes previously adhering to the granular particles of the ore, This mechanical cleansing of mineral surfaces may be the direct cause of the benefits obtained by our use of cyanide, although it is possible that the dispersion of slimes is a mere indication of a more fundamental chemical cleansing, such as a removal of metal ions from certain minerals that would otherwise be objectionably activated or depressed. Whatever function may be attributed to the cyanide as used in our process, it does bring about an effective water-wetting of the minerals of class I together with a much improved selectivity of positive-ion agents for the minerals of each of the two classes II and III. We have noted in particular the. correcting effect of cyanide in those cases where the collective separation of step B by positive-ion agent treatment could not otherwise be satisfactorily carried out.

As the cyanide we can use any cyanide to advantage, but prefer to use an alkali metal cyanide, such as sodium cyanide. It is possible to add the cyanide to the pulped ore together with the positive-ion agent employed, although it is often desirable to preliminarily condition the pulped ore for a suitable periodwith the cyanide alone. The amount of cyanide required is ordinarily not very large, good results being frequently obtained with as little as 0.5 lb. of alkali cyanide per ton of ore. However, the amount of cyanide used may haveto be increased considerably beyond this level if such consumers of cyanide as cyanicides are present in either ore or water.

If desired, the cyanide-may be employed in conjunction with a small quantity of an alkali metal carbonate. This in many cases may be found useful, especially if the water used is not soft. In some cases, it may also be found useful to employ a minute quantity of alkali silicate.

It is our further discovery that the collective separation peculiar to step B can be more effectively carried out by employing the positive-ion agent in conjunction with a hydrocarbon oil, which by itself is usually worthless. This oil is one preferably composed of hydrocarbons of a boiling point sufficiently high not to be appreciably volatile at ordinary temperatures and also one not too viscous nor yet too fluid. Suitable oils' for this purpose are lubricating oils and the cheaper fuel oils. The use of fuel oils is particularly advantageous because of those impurities in such oils which are eflective in as- (a) A conditioning sub-step, in which the ore particles in aqueous suspension are acted upon by the agent; and

(b) A separation sub-step, in which the mineral particles adhering to gas are separated from the mineral particles adhering to water.

In carrying out the conditioning sub-steps (a), any suitable mixing device may be used in which the ore pulp is thoroughly admixed with the agents by agitation. Such devices thus include special conditioning tanks, barrel-type mixers, grinding mills, and even conveying launders. As-to the separation sub-steps (b), these may be carried out in flotation machines of any type, such as mechanically agitated machines, pneumatic machines, etc., or on gravity concentrating devices of any type, such as shaking tables, vanners, etc. Flotation apparatus is preferred if the ore particles are relatively small, while gravity concentrating apparatus is preferred if the ore particles are relatively large.

The process of the present invention may include various auxiliary steps, which will now be described. I

The respective particle sizes at which it is most suitable to carry out the aforementioned principal steps A to C are determined by the degree of locking in the ore. In some cases, of course, a single preliminary crushing and grinding of the ore is all that is required to properly liberate all of the minerals which are to be separated from one another. Whenever possible, however, we have found it more advantageous to carry out the initial crushing and grinding operation for an adequate liberation of the minerals of one class only and to employ a further grinding operation at a later stage of the process for an adequate liberation of the minerals of each of the other two classes. If step A is to be employed, for example, the ore may be initially crushed and ground to adequately liberate the minerals of class III and thus enable the carrying out of step A, after which the product to undergo separation by step B may be ground for an adequate liberation of the minerals of each of classes I and II. Or, if step A is to be omitted, the ore may be initially crushed and ground to adequately liberate the minerals of class I and thus enable the carrying out of step B, after which the product to undergo separa tion by step C may be ground for an adequate liberation of the minerals of each of classes 11 and III. By such procedures, improved metalone or both of the fractions. For example, step A alone or steps A and B alone may be carried out on one fraction, while step B alone or steps B and C alone may be carried out on the other fraction. Obviously, such procedures are also effective in bringing about improved metallurgical results.

In this connection it should be noted that the presence of slimes in the carrying out of the collective separation of step B by positive-ion agent treatment is not nearly as harmful as it. would otherwise be without the additional use of a cyanide. However, the carrying out of this collective separation in the absence of the finest slimes may frequently be of advantage, especially from the standpoint of reagent consumption. This also applies to the carrying out of either of the separations of steps A and C by negative-ion agent treatment. If desired, therefore, the process of the present invention may include the number of desliming operationsnecessary to insure the absence of the finest slimes in the carrying out of its various separations.

In addition to the auxiliary steps which have been described, the process of the present invention may include a removal of the effect which the positive-ion agent and hydrocarbon oil of step B would otherwise have in the product to undergo separation by step C, as well as a removal of the effect which the negative-ion agent and hydrocarbon oil of step A would otherwise have in the product to undergo separation by step B. Each of these auxiliary steps may be carried out inany known manner and, if desired, carried out simultaneously with a grinding of the product to undergo further separation. Some chemical treatments which we have found useful for removing the effect of the positive-ion agent and hydrocarbon oil of step B will be described hereinafter.

Obviously, the usual dewatering of the prod-v ucts to undergo further separation may also be included in the process of the present invention.

thus desirable in the practice of any of the afore-' mentioned principal steps of our process.

Most positive-ion agents operate within the range of pulp-pH. values 3.0 to 10.0. However, the optimum range for agents of this type is usually appreciably narrower than this range,- 'although wider by their use in conjunction with cyanide than would otherwise be permitted. A fairly safe range of pulp-pH values within which to operate by our use of cyanide may in many cases be from 5.0 to 9.0, it being understood that the optimum range in each case largely depends upon the particular positive-ion agent employed. This range, of course, is one which canv be easily ascertained by preliminary experimentation.

0n the other hand, most negative-ion agents operate within the range of pulp -pH values 7.0 to 12.0. When using soaps and soap-like agents, the best results are usually encountered within the range 8.0 to 10.0. When using xanthate-' type agents for the indiscriminate flotation of stearyl quinolinium sulfate.

Any known apparatus of the proper type may iron sulfide. selective flotation operation is also the use of .negative-ion agents,- it can obviously be carall sulfides, the pulp can well have a pH value as low as from 7.0 to 8.0. But tor selective flotation of sundry sulfides by the use of xanthatetype agents, the pulp is preferably adjusted to a pH value of from 8.0 to 10.0, if galena is'to be floated preferentially to iron sulfide, and to a pH value of from 9.0 to 12.0, if sphalerite or copper sulfide is to be floated preferentially toiron sulfide.

As we have found, material benefits may be obtained in the practice of our invention by the use of purified water, especially in the carrying out of the collective separation of step B by positive-ion agent treatment.

The process of the present invention has been carried out with many agents of both the positive-ion type and the negative-ion type. As positive-ion agents we have used alkyl amine salts such as lauryl amine hydrochloride and stearyl amine sulfate; alkyl pyridinium salts .such as lauryl pyridinium hydrochloride and stearyl pyridinium sulfate; and alkyl quinolinium salts such as lauryl quinolinium chloride and As negative-ion agents we have used fatty acid soaps such as sodium oleate and palmitate; xanthates such as potassium ethyl xanthate; substituted .thioureas such as di-phenyl thio-urea; as well as various di-thio phosphates, alkyl tri-thio carbonates, and alkyl sufonic acid'salts.

In the Butte ores of the Emma Mine there occur large quantities of manganese carbonate admixed with various sulfides and silicon-bearing minerals, the sulfides contained in these mixtures including those of iron, 'zinc, lead, and copper. By treatment of these ores with a positive-ion agent in conjunction with cyanide (prefcyanide), the sulfides and silicon-bearing minerals can be collectively separated from the manganese carbonate, which is an application of the aforementioned principal step B of our process. After removal of the effect of the positiveion agent and hydrocarbon 'oil contained in the as mixed sulphide and siliconbearing minerals, the sulfides can then be collectively separated from the silicon-bearing minerals treatment of such product with a negative-ion agent (together with hydrocarbon oil, if desired), which is an application of the aforementioned principal step C of our process. Subsequently, the sulfides can be separated from each other in accordance with known methods. For example, lime andcyanide can be used to permit floating the lead and copper sulfides away from the iron and zinc'sulfldes, subsequent to which lime and copper sulfate can be used to product separated permit floating the zinc sulfide away from the Since the cardinal feature of this ried out without the step of collective separation of the various sulfides from the silicon-bearing minerals.

when carrying out the process of the present invention in accordance with the Butte ore procedures above. mentioned, 'all that is actually required for removing the effect of positive-ion agent and hydrocarbon .oil prior to separation of the sulfides from the silicon-bearing minerals is that such effect be obliterated with reference to the silicon-bearing minerals. By sulphuric acid treatment, for example, the positive-ion agent and hydrocarbon oil are only in part wasted by removal of their effect on the silicon-bearing minerals, the other part being used to keep the sulfide minerals attachable to gas bubbles and thus assist in their subsequent separation.

On the other hand, it is possible to remove the effect of positive-ion agent and hydrocarbon oil from the sulfides, as well as from the siliconbearing minerals. This can be done in many ways. The effect of hydrocarbon oil can be overcome with reference to all minerals by its dispersion in an alkaline solution, which can be soda ash, lye, water glass, sodium sulfide, ammonia, lime, etc. As to the positive-ion agent, its efiect can be overcome with reference to all minerals by tying it up by the use of alkaline silicates. As another possibility, the positiveion agent can be destroyed by either oxidizing agents or metallic salts in either acid or alkaline baths. 'This destruction of the positive-ion agent can thus be accomplished by the use of ammonium persulfate which gives a slightly acid reaction, also by the use of copper and ferric sulfates in ammonia or lye of suitable concentration.

The removal of the efiect of positive-ion agent and hydrocarbon oil either with reference to silicon-bearing minerals alone or with reference to both sulfides and silicon-bearing minerals need not be complete, but in any case more effective separation of the sulfides results if the silicon-bearing minerals have largely. removed from their surfaces the effect of positive-ion agent and hydrocarbon oil.

Any one of the aforementioned chemical treatments useful in removing the effect of positive-ion agent and hydrocarbon. oil can be carried out in any known apparatus suitable for the purpose intended. A tank of the mixing or conditioning type may thus be used, the con- .taminated liquor being discharged at the top of the tank and the wash liquor at the bottom with the treated minerals. A series disposal of such tanks can be used with countercurrent flow of the liquors, as in many other metallurgical processes. If desired, the conditioning and separating phases can be segregated. For example, the conditioning phase may be carried out in a barrel-type mixer and the separating phase in a hydraulic classifier.

In applying our process to various ores, we have noted the erratic'response of some to positive-ion agent treatment, as carried out without the use of cyanide. This we found to be true in the case of the aforementioned Butte ores from the Emma Mine. It is a fact that some choice samples from this mine do not require the use of cyanide to besatisfactorily separated by positive-ion agent treatment. Yet the results of our practice of this'step without the use of cyanide on other samples of the Emma Mine, even taken from the same deposit, were far from being commercially acceptable. By. the use of cyanide, it has been our experience that this erratic response of some ores to positive-ion.

agent treatment can in all instances be corrected to an extent such as to permit their being consistently satisfactorily. separated in accordance with such treatment. Even where the use of cyanide is not required for satisfactory separation by positive-ion agent treatment, wehave found this separation to be materially improved by the use of cyanide.

Although the following example made no use of cyanide in effecting separation by positiveion agent treatment, it is otherwise representative of procedures that have been found particularly satisfactory in the practice of such separation.

Exsm'm: 1

A choice sample of Butte ore from the Emma Mine was ground and thereafter deslimed to free it of particles finer than 350 mesh. The deslimed sample was then separated into a coarse fraction of 14 to 65 mesh and a fine fraction of 65 to 350 mesh. The coarse fraction was conditioned in thick pulp for about two minutes with 0.25 lb. of lauryl amine hydrochloride and 5.0 lbs. of fuel oil, both per ton of ore, while the fine fraction was conditioned in thick pulp for about ten minutes with 0.4 lb. of lauryl amine hydrochloride, 5.0 lbs. of fuel oil, and 0.05 lb of octyl alcohol as a frothing agent, all per ton of ore. Subsequently, the coarse fraction was treated on a shaking table and the fine fraction in a subaeration flotation machine, tap water being used in each of these operations. The results of the test are .shown in the following tables:

Tcbllna operation Percent recover- Percent assays ies on coarse Xeight fraction Product cent of s- I a es es Mn Ins. (a? Mn Ins.

pr n) 1m Ooarseiraction.-- 64.0 34.2 2.5 5.5 Concentrate (tableend). 45.5 44.2 2.9 1.0 91.8 9.2 11.0 'Tailing (table side) 18.5 10.0 71.3 12.0 8.4 00.8 no

Flotation operation mu Percent recoveries weight P t on line fraction in per Product cent of sub ML original iides iides feed I Mn Ins. my Mn Ins. my

pr n) pr 'Finefraction 21.0-30.0 25.0 so

Concentrate (non- 19.5 45.8 2.5 0.5 94.9 7.0 8.0 Tallinl floated)" 7.5 6.2 78.4 15.0 5.1 93.0 99.0

Remand slim Percent clays Weight in peroentokoriginal feed Mn Int sulfides Overall mull:

- Percent re- Xeg ht Percent snsyc mum Product cent of Buliides feed Mn Ins. (puma Mn Ins.

Combined concen- 05.0. 44.1 2.7 1.0 84.5 Combinedtailings" M0 8.8 78.4 13.0 sao Ooncs.+slime 7L0 42.7 6.8 2.0 904 Tails,+slime 85.0 15.8 50.8 11.0 02.4

The following two examples are illiutrative of procedures which can be used subsequent to effecting separation by positive-ion agent treatmeat. I

' effect of both positive-ion agent and hydrocarbon.

The combined silica-silicate-sulfide tailings obtained by tabling and flotation treatment of Butte ore with podtive-ion agent and hydrocarbon oil positive-ion agent. Thereafter, the sample was subjected to flotation with 2.0 lbs. of kerosene and 0.15 lb. of sodium ethyl xanthate, both per ton of dry feed, the kerosene being used as adroth conditioner. The results are shown in the following table, it'being noted that a ratio of appropriately 15 to 1 was obtained between the sulfur assays of concentrate and tailing, which constituted large sulfide recovery:

. to carryout this the results ofwhich were asfollows:

Percent assays Psrcentreeozeries Product W 3 M11 Ins. Zn m Ins. ZnS

Feed as: no mar Concentrate (1st residue) e 31.0 52- 0.40 70.1 13.5. 12.5 Middling(2ndresidu 19.0 2L4 47.9 0.68 14.4 40.2 5.5 Tailing(lstfloat) 21.0 8.1.49.6 5.20 5.5 no 55.0

. Exmts 5 The conditions of this test were identical to those of Example 4 except for the following indicated differences. The preliminary conditioning of the pulp was carried out for one hourwith the sodium cyanide employed in the reduced amount of 5 lbs. per ton of ore. Also, the positive-ion agent used in flotation was lauryl pyridinium iodide, which was added in the amount of 1.5 lbs. per ton of ore. No cleaning was carried out on the floated silico-silicate-sulphide product.

p t way; As in Example 4, soft water was used. The fol- Product lowing results were obtained in this instance:

ms. Sulfur Percent assays Percent recoveries Concentrate (floated) .310 10.8 Product 3%: W floated) f -6 7 M Zn 2 Exams 3 F 2&2 23.0 220 4 Concentrate (mi- 58.0 401 a5 0.35 82.5 as 8.7 n h sample 0! the same wmbined timings .r fl iii'dfiblllfi 42.0 1110 50.0 5.10 17.5 51.2 91.3 as in Emmple 2 was ground in the same manner, but in this instance in the presence of 5.0 'lbs. of Exam, 6

sulphuric acid per ton of dry feed. The purpose of this treatment was to selectively remove the oil from the silicon-bearing minerals. Thereafter, the sample was mixed with0.2 lb. of sodium ethyl xanthate and 0.05 lb. of pine oil as a frothing agent, both per ton of dry feed, after which flotation of the sulfides was carried out.- The results are shown in the following table, it being noted that a ratio of approximately 31 to 1 was obtained between the zinc assays of concentrate and tailing, which amounted to large zinc recovery:

Percent assays Product Zn Pb Fe Ins.

Concentrate some) "21.5 an 7.89 0.04 Telling (nonoated)- 0.06 0.16 0.6 54.5

The following three examples appertain to our use of cyanide for improved separation by positive-ion agent treatment, the samples of Butte ore taken in these examples being each of' suchcharacter as to normally preclude successfulseparation. Exams: 4'

A pulp of Butte ore from the Emma Mine, ground to flotation size, was conditioned for thirty minutes with 8 lbs. of sodium cyanide'and 8 lbs. of sodium carbonate, both per ton of ore.

Thereafter, the pulp was subjected to flotation with 0.4 lb. of lauryl amine hydrochloride, 12 lbs.

of fuel oil,.and 0.05 lb. of pine oil, all per ton or 1 passed over a Wilfley concentrating table. Somewhat hard tap water was used throughout the procedures of the test. As can be seen from the following table, the concentrate was of commercial grade for rhodochrosite, but the recovery was only fair, which was largely due to the presence of locked particles of rhodochrosite with silica, it being obvious that the tailing could have been reground and subjected to flotation, thereby increasing the recovery:

. Percent assays Percent recoveries Percent weight Mn Ins. 8 Mn Ins. B

Product Concentrate (table and) l4. 2 Telling (table side)- 47. i

The following test'was carried out without cyanide, with the result that no useful separation was effected.

Comparative test A sample taken irom the same lot as the sample of Example 6 was formed into an aqueous pulp,

with which were mixed 8 lbs. of fuel oil and 0.25 lb. of'lauryl amine hydrochloride, both per ton of ore, the pulp being thereafter subjected to separation on a shaking table with the following results:

t Percent ways Percent recoveries Product weight Mn Ins. 8 Mn Ins. 8

Feed 27. 7 28. 9 2. 9 Concentrate (table en 63. 0 30. 5 22. 0 1. 8 69. t 47. 9 39. 1 Tailing (table side)- 37. 0 22 9 40. 5 4. 8 30. 6 52. l 60. 9

In the following example carried out on a difierent ore, useful separation was obtained without cyanide, but the results could have been improved by its use.

EXAMPLE 7 A minus 20-mesh deslimed sample of Illinois ore composedin large part of galena, sphalerite, quartz, fluorite, and calcite was conditioned for two minutes with 0.25 lb. of lauryl amine hydrochloride and 6.0 lbs. of fuel oil, both per ton of ore, and then passed over an ordinary Wilfiey table, the sulfides and quartz going to the side and the fluorite and calcite to the end. The metallurgical results were as follows:

separated sulfides and silica from siderite (iron carbonate), from hematite and magnetite (iron oxides), and from magnesite (magnesium carbonate) and limestone. Each of these separations was also found to be materially improved by the use of cyanide.

It is understood that the term "ore used in the claims is meant to include any mixture of the minerals mentioned.

What is claimed is:

1. A process of concentrating an ore containing at least one non-sulfide non-silicon-bearing mineral, at least one metalliferous sulfide mineral, and at least one silicon-bearing gan mineral; which'comprises agitating an aqueous suspension of such an ore in the presence of a positive-ion agent and a cyanide, and subsequent:-

ly separating the particles of metalliferous sul-.

fide and silicon-bearing gangue mineral adhering to gas irom the particles of non-sulfide non-silicon-bearing mineral adhering to water.

2. A process of concentrating an ore containing at least one non-sulfide non-silicon-bearing mineral, at least one metalliierous sulfide mineral, and at least one silicon-bearing gangue mineral; which comprises agitating an aqueous suspension or such an ore in the presence of a positive-ion agent and an alkali metal cyanide. and sub'se-r quently separating the particles oi metallii'erous sulfide and silicon-bearing gangue mineral adhering to gas from the particles or non-sulfide nonsilicon-bearing mineral adhering to water.

3. A process of concentrating an ore containing at least one non-sulfide non-silicon-bearing mineral, at least one metalliferous sulfide mineral, and at least one silicon-bearing gangue mineral; which comprises preliminarily conditioning an aqueous suspension of such an ore'with a cyanide, subsequently admixing the suspension with a positive-ion agent, and subsequently separating the particles of metalliferous sulfide and siliconbearing gangue mineral adhering to gas from the particles of non-sulfide non-silicon-bearing mineral adhering to water.

4. A process of concentrating an ore containing at least one non-sulfide non-silicon-bearing mineral, at least one metallii'erous sulfide mineral, and at least one silicon-bearing gangue mineral;

' which comprises preliminarily conditioning an aqueous suspension of such an ore with an alkali metal cyanide and an alkali metal carbonate,

' subsequently admixing the suspension with a posi-'- tive-ion agent, and subsequently separating the particles of metalliferous sulfide and silicon-bearing gangue mineral adhering to gas from the particles of non-sulfide non-silicon-bearing min- 1 eral adhering to water.

5. A process of concentrating an ore containing at least one non-sulfide non-silicon-bearing mineral, at least one metalliierous sulfide mineral, and. at least one silicon-bearing gangue mineral; which comprises agitating an aqueous-suspension of such an ore in the presence of a positive-ion agent, a hydrocarbon oil, and a cyanide; and subsequently separating the particles of metaliiferous sulfide and silicon-bearing gangue mineral adhering to gas from the particles of non-sulfide non-silicon-bearing mineral adhering to water.

6. A process of concentrating an'ore containing manganese carbonate admixed with at least one metalliferous sulfide mineral and at least one silicon-bearing gangue mineral, which comprises agitating an aqueous suspension of such an ore in the presence of a positive-ion agent and a cyanide, and subsequently separating the particles of metalliferous sulfide and silicon-bearing gangue mineral adhering to gas from the particles of manganese carbonate adhering to water.

7. A process of concentrating an ore containing manganese carbonate admixed with at least one metallifercus sulfide mineral and at least one silicon-bearing gangue mineral, which comprises agitating an aqueous suspension or such an ore in the presence 01' a positive-ion agent, a hydrocarbon oil, and a cyanide; and subsequently separating the particles of metalliferous sulfide and silicon-bearing gangue mineral adhering to gas from the'particles of manganese carbonate adhering to water. v

8. Aprocess of concentrating an ore containing calcite admixed with at least one metalliferous sulfide mineral and at least one silicon-bearing gangue mineral, which comprises agitating an aqueous suspension of such an ore in'the presence of a positive-ion agent and a cyanide, and subsequently separating the particles of metalliierous sulfide and silicon-bearing gangue mineral adhering to gas from the particles of calcite adhering to water.

ANTOINE M; GAUDIN. JOHN DIXON VINCENT.

7 CERTIFICATE OF CORRECTION. Patent no. 2,195,72h. April 2', 191m.

' ANTOINE n.- GAUDIN, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, first column, line 8, before the word "In" insert the following sentence The process of the present invention may also include a preliminary desliming of the ore, as wellas a desliming of any of itsobtained products to undergo further separation.

and second column, 1ine-l .8, after "minerals" insert --by--; page 5, first column, line 72,'for"or" read of; and second column, line 214, for "silicosilicate-sulphide" read- --si lica-si1icate-sulphideand that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case. in the Patent Office.

Signed and sealed this 11th day of June, A. 13'. 191p.

Henry Van Arsdale; (Seal) Acting Commissioner of Patents.