CA1340043C

CA1340043C - Reactive derivative of zirconium and its preparation

Info

Publication number: CA1340043C
Application number: CA000594043A
Authority: CA
Inventors: Joseph Recasens; Daniel Urffer; Pierre Ferlanda
Original assignee: Societe Europeenne des Produits Refractaires SAS
Current assignee: Societe Europeenne des Produits Refractaires SAS
Priority date: 1988-03-22
Filing date: 1989-03-17
Publication date: 1998-09-15
Anticipated expiration: 2015-09-15
Also published as: JPH0459250B2; DE68903017D1; DE68903017T2; FR2629070A1; CN1038074A; EP0334732B1; BR8901329A; ATE81104T1; CN1015439B; FR2629070B1; JPH01278417A; EP0334732A1

Abstract

The invention relates to the chemistry of zirconium.
It relates to reactive derivatives of zirconium, characterized in that they are in the form of a pulverulent white solid which is not crystallized and dry in appearance, and consist of metazirconic acid ZrO(OH)2 accompanied by free or weakly bound water, it being possible for some of the OH- ions to be replaced by halide ions, the ZrO2 content of these derivatives being from 60 to 92% by weight inclusive and the water content of these derivatives ranging from 3 to 40% and the halide ion content of these derivatives being capable of ranging up to approximately 5% by weight, and to a process for their preparation.
The solid derivatives of the invention can be easily converted into usual reactive derivatives of zirconium by reaction with an aqueous solution of an acid.

Description

13~0~3 New reactive derivative of zirconium and its preparation The invention relates to a new reactive deriva-tive of zirconium and to its preparation.
The term "reactive derivative of zirconium" de-notes a zirconium compound which is in solution in an aqueous or organic solvent or can be dissolved in such a solvent. The reactive derivative of zirconium can react in the dissolved stste with other compounds.
Many reactive derivatives of zirconium are known. Among these, those most commonly employed in in-dustry are the following:
basic zirconium csrbonate (C02/ZrO2 ~ 0.5) con-taining 40% by weight of ZrO2, in the form of moist paste, zirconium orthosulphate (sulphate/ZrO2 ~ 2) either in the form of aqueous solution (containing 18%
by weight of ZrO2), or in the form of crystallized solid (containing 32% by weight of ZrO2), zirconium oxychloride (chloride/ZrO2 ~ 2~
either in the form of aqueous solution (containing 20%
by weight of ZrO2) or in the form of crystallized solid (cont~ining 33% by weight of ZrO2), ba ic zirconium sulphate (sulphate/ZrO2 ~ 0.6 to 1) in the form of moist paste (containing 37% by weight of ZrO2), zirconium nitrate in the form of aqueous solu-tion (containing 19% by weight of ZrO2) or of solid ~containing 40% by weight of ZrO2), zirconium acetate in solution (containing 22 by weight of ZrO2), zirconium hydroxide (containing 42% by weight of ZrO2), and zirconium ammonium carbonate in solution (con-taining 13% by weight of ZrO2).
Many organic derivatives of zirconium are also known (propionate, lactate, acetylacetonate, various alcoholates), whose ZrO2 content ranges from 6 to 15 *

- 2 - 13~ 0 0 ~ 3 by weight.
These materials are employed as such (in the case of derivatives in ~olution) or must be di~601ved by reaction with a solution, generally acidic, by the final u6er ~in the ca~e of derivative~ which are solid or in paste form).
In practice, only the zirconium present in the abovementioned materials is generally utilized, and not the anions (for example chloride, carbonate, sulphate, nitrate or acetate) and/or the water, even though they form the greater part of these materials, their role being essentially to keep the zirconium in a soluble form. The anions and/or the water do not directly participate in the reaction~ involved in the practical applications of these materials and are, in fact, rather detrimental. In fact, solutions of zirconium compounds are corrosive and toxic, and this presents problems in storage and in transport, and pastes based on zirconium compounds are heterogeneous because of the presence of free water and are difficult to handle.
Furthermore, certain anions ~particularly ~ulphates and chlorides) or water can oppose the required reactions, for example during the production of driers of the zir-conium soap type. Finally, from an economic ~t~n~roint, it is not very advantageous to transport materials con-taining relatively little active material (ZrO2) and to have to employ costly containers capable of resisting corrosion, in the case of materials in the form of solutions or of pastes.
It is therefore advantageous to be able to have available reactive derivatives of zirconium with a high Zr~2 content, which are solid materials containing a minimum of impurities and of water.
The objective of the invention is to provide such reactive derivatives of zirconium.
More particularly, the invention relates to re-active derivatives of zirconium, characterized in that they are in the form of a pulverulent white solid which is not crystallized and dry in appearance, soluble in ~ 3 ~ 13400~3 an aqueou~ solution of an acid, and consist of metazirconic acid ZrO(OH)2 accompanied by free or weakly bound water, it being possible for some of the OH ions to be replaced by halide ions, the ZrO2 content of the~e derivatives being from 60 to 92% by weight inclusive, preferably from 75 to 86,5~ by weight, and the water content of these derivatives ranging from 3 to 40%, preferably 13 to 25%, and the halide ion content of these derivatives being capable of ranging up to approximately 5%.
The derivatives of the invention usually con-tain traces of halide ions originating from impurities present in the raw materials. However, in the present description it is considered that the derivatives of the invention are free from halides when their halogen content is below 0.02% by weight within analytical accuracy. A class of preferred derivatives is that of the derivatives containing, on a weight basis, ~5 to 86.5%of ZrO2, 13 to 25% of water and not more than approximately 0.5~ of halide ions, in particular Cl-ions. Another class of preferred derivatives is that of the derivatives containing, on a weight basis, less than 13% of water and more than 0.5% of halide ion~, in particular Cl- ions.
The invention also relates to a process for the preparation of the abovementioned reactive derivatives of zirconium, characterized in that it comprises the steps consisting in:
a) preparing water-rich zirconia hydrate ZrO2.2H2O or zirconium hydroxide Zr(OH~4, b) optionally, replacing some of the OH- ions in the product of step (a) with halide ions, and c) partially dehydrating, in a controlled man-ner, the product of step (a) or (b) by heating to a temperature of not more than 130~C until a pul~erulent white solid is obtained, which is not crystallized and dry in appearance and soluble in an aqueous solution of an acid.
The first step (a) consists in preparing - 4 ~ 0~3 water-rich zirconia hydrate ZrO2.2H20, al80 called zirconium hydroxide Zr(OH)4. ~Water-rich~ means a product contAining at least 45% by weight of water in total (free water + bound water). Thi~ step may be performed in various way~, ~uch as, for example:
- Neutr~lization of an acidic aqueous solution of a Zr ~alt (for example the oxychloride, nitrate or acetate), with a base (for example sodium hydroxide, aqueous ammonia), followed by filtration and wa~hing of the filter cake. A bulky and water-rich (gO~ and more) pre-cipitate of zirconia hydrate or zirconium hydroxide i~
thus obtained.
This method offers the advanta~e of providing a pure product freed from the impurities which may be present in the startinq salt.
- Hydrolysis of an organic zirconium salt in solution in water or a water-alcohol mixture, followed by fil-tration and washing of the filter cake. However, thi~
method is not advantageous from an economic stand-point, because an organic Zr salt must be available.
- Displacement of ions from a solid basic Zr salt with a reactant in aqueous solution or water, dep~n~ing on circumstances, followed by filtration and washings of the filter cake. A ~'basic" Zr sulphate (reactant: base in aqueous solution) or an alkali metal zirconate such as sodium zirconate (reactant: water) may be employed, for example, as a basic Zr ~alt. This method is the preferred method from the point of view of cost. It also makes it pos~ible to obtain a reactive derivative of zirconium with a reduced content of free or weakly bound water. It has the possible disadvantage of leav-ing fairly high residual contents of sulphates in the final product, (in the ca~e of a basic Zr sulphate) or of alkali metal oxides (in the case of an alkali metal zirconate). However, when the optional step ~b) is used, the alkali metal oxides are found to be practi-cally eliminated.
The optional step ~b) of partial substitution of the OH- ions in the product of step ~a) by halide i ~
13400~3 s ion~ makes it possible to obtain reactive derivatives of zirconium with higher ZrO2 contents. This step, which i~ used when a halide ion content above 0.02% i~
de~ired, may be conducted by washing the product of S step (a) with an aqueous solution of the corresponding hydrohalogenic acid. In the case of washing with hydro-chloric acid which is intended to substitute Cl- ions for OH- ions, a Cl- ion content of the order of 5% by weight can be attained, but the final content can be ad~usted by carrying out a second washing with the aid of aqueous ammonia, for example. In the case where the product of step (a) has been obtained by displacement of ions from an alkali metal zirconate, such as Na zirconate, the ~ub~titution of OH- ions by halide ions, for example Cl-, can be carried out by wsshing the product of step (a) with an aqueous solution of ammonium halide, for example ammonium chloride, optionally acidified with hydrochloric acid. The residual sodium is thus displaced with a controllable quantity of Cl by adjusting the pH of the washing solution. A subsequent w~shing with another acid allows the corresponding anions to be fixed, even if the latter do not contribute to the stability (in the case of washing with HN03 in example 5).
The controlled dehydration step (c) may also be performed in various ways. This dehydration may be car-ried out merely by heating the product of step (a) or (b) in an oven at a temperature not exceeding 120~C in the case of a nonhalogenated product and not exceeAing 130~C in the case of a halogenated product (that is to say one in which halide ions have been substituted for some of the OH- ions)~ in the case of a relative atmospheric humidity of 50 to 70%. The dehydration begins already at 30~C but is slow at this temperature.
The operation will be preferably carried out between 80 and 110~C. The degree of dehydration obtAine~ will obviously vary with the temperature employed and the degree of heating. The dehydration can also be per-formed by heating using microwaves. This heating method - 6 - ~3~00~

is highly effective and rapid. An excessively severe heating, which would result in the decomposition of ZrO(OH)2 with production of insoluble zirconia (that i~
to nay of crystallized zirconia) and water, must be avoided in any case.
The reactive derivatives of zirconium of the invention can be easily converted into the usual reac-tive derivatives of zirconium. It suffices to dissolve the derivatives of the invention in an aqueous solution of an acid, for example of hydrochloric acid to obtain zirconium oxychloride, of nitric acid to obtain zirconium nitrate, and so on. The high solubility of the derivatives of the invention can be attributed to the pre6ence of zirconyl ions ZrO2+.
The reactive derivatives of zirconium of the invention are remarkably stable. After a period of 15 days at 80~C, their solubility in a hydrochloric acid solution remains higher than 95%, whereas it is then only 50% in theicase of basic zirconium carbonate.
Depe~ing on their purity, the derivatives of the invention can be employed as a source of Zr in various industrial applications. By way of indication, there may be mentioned:
- the treatment of TiO2-based pigments, the derivative of the invention being dissolved in situ in a hydro-chloric or sulphuric medium, - the treatment of petroleum formations, it being pos-sible for the derivative of the invention to be dis-solved on Si~ in hydrochloric acid.
The following examples, which do not imply any limitation, are given for --------- illustrating the invention.
Example 1 55 parts by weight of zirconia ~natural oxide known as baddeleyite or thermal oxide) wi~h an ave-age ~r-ticle size of 0.6 to 15 ~m are mixed with 45 parts by weight of NaOH in the form of solid pellets or of con-centrated aqueous solution. The mixture is heated to 850~C for 1 hour to obtain, after cooling, a solid mix-_ 7 _ l~n~

ture of sodium zirconate and excess sodiu~ hydroxide.
This mixture is brought into contact with water at 60~C, with stirring (water/mixture weight ratio:
2.5/1). The suspension obtained is filtered and the filtration residue is then washed in a stream of water (water/product weight ratio: 20/1). The product ob-t~ine~ is washed with a 0.lN aqueou~ ~olution of HCl (solution/product weight ratio: 30/1), and then with water ~water/product weight ratio: 5/1). The moist paste obtained i8 then dehydrated for 24 hours at 40~C
at 50-70% relative humidity. The pulverulent solid pro-duct finally obtained contains, on a weight basis, approximately 75% of ZrO2, 20% of H20, 5% of Cl and les~ than 0.5% of various impurities.
Example 2 The operating procedure of example 1 is repea-ted as far as the first washing of the filtration resi-due with water, inclusive. The product obtained is then washed with a concentrated (100 g~l) solution of ammo-nium chloride (NH4Cl solution/product weight ratio:
3/1) and then with water (water/product weight ratio:

5/1). The resulting product is then dehydrated by heat-ing to 80~C for 6 hours at 50-70% relative humidity.
The pulverulent solid product finally obtained con-tains, on a weight basis, 84% of ZrO2, 15% of H20, 0.5~
of Cl- and approximately 0.5% of impurities (mainly Na20 ) .
Example 3 The operating procedure of example 1 is repea-ted as far as the first washing of the filtration resi-due with water, inclusiv~. The product is then dehydra-ted at 80~C for 12 hour~ at 50-70% relative humidity.
The pulverulent solid product finally obtained con-tains, on a weight basis, 82% of ZrO2, 13% of H20 and 5% of Cl- and less than 0.5% of impurities (mainly Na20 ) .

- 8 - 13~0~3 Example 4 1 kg of basic zirconium sulphate, obtained as described by F. ~arnworth, S.L. Jones, I. ~cAlpine, "The production, properties and use of zirconium chemicals", Special Publication of the Royal Soc. of Chemistry, No. 40, p. 259 ~1981), is suspended in 9 litres of O.lN aqueous ammonia solution. The pH of the mixture obtained is approximately 7. After stirring at 25~C the product is filtered and the filter cake i~
washed ~ith 5 litres of water. The product obtained is then dried at 80~C for 12 hours at 50-10% relative humidity. The solid product finally obtained contains, on a weight basis, 82% of ZrO2, 13% of H2O and 5% of impurities (mainly sulphate ions). It should be noted that the aqueous ammonia could be replaced with another base.
Example 5 The operating procedure of example 1 is repea-ted as far as the first washing of the filtration resi-due with water, inclusive. The product obtained is washed with a O.lN aqueous solution of nitric acid (acid solution/product weight ratio: 30/1). The product is then dehydrated at 80~C for 12 hours at 50-70% rela-tive humidity. The pulverulent solid product finally obtained contains, on a weight basis, 82% of ZrO2, 13%
of H20 and 5% of impurities (mainly nitrate ions).
Example 6 The operating procedure of example 1 is repea-ted as far as the washing with hydrochloric acid, inc-lusive. The product is then dehydrated at 120~C for 12 hours at 50-70% relative humidity. The pulverulent solid product finally obtained contains, on a weight basis, approximately 92% of ZrO2, 3% of H2O, 5% of Cl-and less than 0.5% of Lmpurities.
Example 7 Preparation o~ a zirconium oxychloride solu-tion containing 20~ of ZrO2 The product of example 2 is added to a 37%
strength aqueous solution of hydrochloric acid in such quantities that the molar ratio Cl/ZrO2 i5 equal to 134~ 3 g approximately 2; the whole is heated to 100~C for 30 minutes and water is then added to ad~ust the relative density of the resulting solution to 1.37, and the lat-ter i8 then cooled to ambient temperature.
Example 8 Preparation of a zirconium nitrate solution contain~ng 20% of Z~~2 The product of example 2 is added to a 65~
strength aqueous solution of nitric acid in such quan-tities that the molar ratio N03/ZrO2 is equal to appro-ximately 2 and that the proportion of ZrO2 i8 approxi-mately 20~ by weight. The whole is heated to 80~C for 1 hour and is then cooled to ambient temperature.
It is self-evident that the embodiments des-cribed are merely examples and that they could be modi-fied, particularly by the substitution of technicalequivalents, without thereby departing from the scope of the invention.

Claims

1. Halogen-containing derivatives of zirconium hydrate, characterized in that they are in the form of a pulverulent white solid which is not crystallized and dry in appearance, soluble in an aqueous solution of an acid, and consist of metazirconic acid ZrO(OH)2 accompanied by free or weakly bound water, wherein some of the OH- ions have been replaced by halide ions, the ZrO2 content of these derivatives being from 60 to 92% by weight inclusive, the water content of these derivatives ranging from 3 to 39.98%, and the halide ion content of these derivatives ranging from 0.02%
to approximately 5% by weight.

2. Reactive derivatives of zirconium according to claim 1, characterized in that they contain, on a weight basis, 75 to 86.5% of ZrO2, 13 to 25% of water and not more than approximately 0.5% of halide ions.

3. Reactive derivatives of zirconium according to claim 1, characterized in that they contain more than 0.5% by weight of halide ions and a proportion of water which is lower than 13% by weight.

4. Derivatives according to claim 1, characterized in that the halide ions are Cl- ions.

5. A process for preparing a halogen-containing zirconium hydrate in the form of a pulverulent white solid which is not crystallized and is dry in appearance, is soluble in acidic aqueous solutions, and consists of metazirconic acid, ZrO(OH)2, accompanied by free or weakly bound water, wherein the OH- ions have been partially replaced by halide ions, said hydrates containing, by weight, 60-92% of ZrO2, 3 - 39.98% of water and 0.02 - 5% of halogen, said process comprising the steps of:
(a) preparing a product comprising a zirconia hydrate ZrO2 ~ 2H2O
or zirconium hydroxide Zr(OH)4 containing at least 45% by weight of free water plus bound water, (b) washing said zirconia hydrate or zirconium hydroxide with an aqueous solution of an ammonium halide to partially substitute halide for OH- ions in said product, and (c) partially dehydrating the product of step (b) by heating to a temperature from 80° to 130° C. to obtain said halogen-containing zirconium hydrate.

6. Process according to claim 5, characterized in that step (a) is performed by displacement of ions from a solid basic Zr salt with a reactant in aqueous solution or water, depending on circumstances, followed by a filtration and washings of the filter cake, wherein the salt is selected from zirconium sulphate and alkaline metal zirconate.

7. Process according to claim 6, characterized in that the basic Zr salt is a basic Zr sulfate and the reactant in aqueous solution is an aqueous solution of a base.

8. Process according to claim 6, characterized in that the basic Zr salt is an alkaline metal zirconate and the reactant is water.

9. Process according to claim 5, characterized in that step (a) is performed by neutralizing an acidic aqueous solution of a zirconium salt with a base, followed by filtration and washing of the filter cake.

10. Process according to claim 5, characterized in that step (b) is carried out by washing the product of step (a) with an aqueous solution of ammonium chloride.

11. Process according to claim 5, characterized in that the heating is carried out with the aid of microwaves.