AU685018B2 - Process for preparing high-purity zirconium oxychloride crystals - Google Patents
Process for preparing high-purity zirconium oxychloride crystals Download PDFInfo
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- AU685018B2 AU685018B2 AU44413/96A AU4441396A AU685018B2 AU 685018 B2 AU685018 B2 AU 685018B2 AU 44413/96 A AU44413/96 A AU 44413/96A AU 4441396 A AU4441396 A AU 4441396A AU 685018 B2 AU685018 B2 AU 685018B2
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G25/00—Compounds of zirconium
- C01G25/04—Halides
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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Description
AUSTRALIA
Patents Act 1990 COMPLETZ SPECIFICATION STANDARD PATENT Applicant: KOREA RESEARCH INSTITUTE OF CHEMICAL TECHNOLOGY 0* 0 0* *0 Invention Title: PROCESS FOR PREPARING HIGH-PURITY ZIRCONIUM OXYCHLORIDE CRYSTALS The following statement is a full description of this invention, including the best method of performing it known to me/us: PROCESS FOR PREPARING HIGH-PURITY ZIRCONIUM OXYCHLORIDE CRYSTALS BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a process for preparing high-purity zirconium oxychloride crystals, in particular, to an improved process for preparing high-purity zirconium oxychloride(ZrOC1 2 8120) crystals through only one crystallization process, which comprises preparing calcium zirconate(CaZrO 3 by pyrogenic reaction of zircon ores and calcium carbonate; precipitating basic zirconium sulfate by dissolving said co\cium zirconate in hydrochloric acid and adding sulfuric acid and alkaline solution to it in order; converting the precipitated basic zirconium sulfate to zirconium hydroxide with ammonia; preparing aqueous is zirconium oxychloride solution by dissolving zirconium hydroxide in hydrochloric acid; evaporating said aqueous zirconium oxychloride solution and adding concentrated hydrochloric acid to it; and crystallizing by cooling the solution to room temperature.
oo *Zirconium oxychloride is widely used as raw materials for mordants 0 and coating agents and high-purity zirconium oxychloride is especially used as essentials to zirconia ceramics.
The industrial method for preparing zirconium oxychloride from zircon consists of two times crystallization. The first crystallization comprises preparing sodium zirconate(Na 2 ZrO 3 by decomposing zircon at high temperature with alkaline decomposition agent containing sodium ion such as sodium hydroxide or sodium carbonate and removing the byi products such as sodium silicate and sodium oxide formed during the reaction with water-washing; preparing the solution of zirconium oxychloride and sodium chloride by dissolving said sodium zirconate in large quantity of hydrochloric acid and filtering to remove some s undissolved components such as silica (SiO) and unreacted ores(zircon); and then, evaporating the solution, cooling and filtering the isolated zirconium oxychloride crystals. But the zirconium oxychloride crystals prepared by the first crystallization process are contaminated with impurities such as silica or sodiuxn chloride. Therefore, in order to get pure zirconium oxychloride crystals, second crystallization should be carried out, which comprises dissolving in water the crystals obtained from the first crystallization; adding hydrochloric acid to this solution; concentrating it with heating; and isolating the crystals with cooling.
But the zirconium oxychloride crystals prepared by the above is conventional method still contain large amount of impurities such as sodium chloride, so multi-step crystallization processes are adapted to reduce the amount of impurities. Accordingly, the yield of zirconium S'.i 'oxychloride crystals is very poor. Thus, according to the above conventional method, not only zirconium oxychloride but also sodium 20 chloride which has low solubility to hydrochloric acid co-exists in said sodium zirconate solution and consequently high- purity zirconium oxychloride crystals cannot be obtained through the crystallization process of separating zirconium oxychloride in the concentrated hydrochloric acid.
Thus, to reduce the contents of sodium chloride in crystals, the zirconium oxychloride crystals are prepared through two times crystallization processes of dissolving the zirconium oxychloride crystals obtained from the first crystallization in water and adding hydrochloric acid, evaporating the solution, cooling and re-crystallizing. As a result, the yield of zirconium oxychloride through the multi-step crystallization is less than 70% and the zirconium oxychloride crystals contain 0.7-2% s sodium chloride as an impurity. Furthermore, the process has some drawbacks that are related with large quantity of hydrochloric acid consumption and great energy supply.
In order to solve the problems related to the impurity of zirconium oxychloride crystals, Jpn. Kokai Tokkyo Koho JP 61-215,217 disclosed a process for preparing zirconium oxychloride crystals, which comprises preparing sodium zirconate by pyrogenic decomposition reaction of zircon with sodium hydroxide and silica removal treatment; dissolving said sodium zirconate in hydrochloric acid and making a solution of sodium chloride and zirconium oxychloride; precipitating only the zirconium component by adding pyridine or ammonia water; dissolving said zirconium precipitates with heating in large quantity of hydrochloric acid and then cooling. This process has no re-crystallization step, but it is very complicate and there are some problems such as the high content of impurities in the product and low yields of the product. Further to this, 20 because large amount of hydrochloric acid is used in this process, it is economically not feasible.
Additionally, Jpn. Kokai Tokkyo Koho JP 63-21,222 disclosed a process for preparing zirconium oxychloride crystals, which comprises preparing sodium zirconate by pyrogenic decomposition reaction of zircon with sodium hydroxide and silica removal treatment; dissolving said sodium zirconate in hydrochloric acid in equavalent ratio of sodium in sodium hydroxide and removing the formed sodium chloride and converting zirconium component into zirconium hydroxide; preparing zirconium oxychloride solution by dissolving said zirconium hydroxide in concentrated hydrochloric acid and cooling. But this process also showed high impurity level in the prepared zirconium oxychloride crystals and the yield of zirconium oxychloride crystals is also low.
In this regard, inventors of this invention have conduced researches on more improved process for preparing high-purity zirconium oxychloride crystals and finally completed this invention to succeed in preparing high-purity zirconium oxychloride needle-like crystals with high yield through only one crystallization process, which is made possible by two facts. One is that the incorporation of impurities into zirconium oxychloride crystals are prevented by converting zircon into calcium zirconate not into sodium zirconate and forming calcium chloride, which has a relative high solubility to hydrochloric acid and than sodium chloride. The other is that this process consists of steps of precipitating basic zirconium sulfate and converting it into zirconium hydroxide.
SUMMARY OF THE INVENTION 20 The object of this invention is to provide a process for preparing high-purity zirconium oxychloride crystals through only one crystallization process via way of preparing some intermediates such as calcium zirconate, basic zirconium sulfate precipitate and zirconium hydroxide.
This invention relates to prepare zirconium oxychloride crystals from zircon (ZrSiO 4 which is characterized as leaching calcium
I
zirconate (CaZrO) with dilute hydrochloric acid, which was formed by pyrogenic decomposition reaction of calcium carbonate and zircon powder; filtering the basic zirconium sulfate precipitates formed by adding sulfuric acid and alkaline solution to said calcium zirconate in hydrochloric acid; filtering zirconium hydroxide precipitates prepared by dispersing said basic zirconium sulfate in water and adding ammonia; and recovering the zirconium oxychloride crystals formed by serialized steps of evaporating aqueous zirconium oxychloride solution prepared by dissolving said zirconium hydroxide in hydrochloric acid, adding concentrated hydrochloric acid, cooling to room temperature and filtering.
DETAILED DESCRIPTION OF THIS INVENTION This invention relates to a process for preparing high-purity zirconium oxychloride crystals through only one crystallization and its 1s detailed description is as follow.
By mixing zircon, which consists of zirconia (ZrO 2 and silica (SiO), with more than 2 molar ratio of calcium carbonate, preferably 2-3 molar "ratio, and reacting the mixture at about 1,250 preferably 1350-1450 t, zircon was composed and converted into some zircon decompositions such 20 as calcium zirconate and clacium silicate. If the used amount of calcium carbonate is less than 2 molar ratio to 1 mole of zircon, calcium zirconate was not produced. Therefore, if the zircon decompositions were leached with dilute hydrochloric acid, calcium silicates were dissolved and removed by filtering and sole calcium zirconate can be prepared. After dissolving in concentrated hydrochloric acid the calcium zirconate powdered through drying, precipitant such as sulfuric acid was added I' and one or more alkaline solution selected from the group consisting of ammonia, sodium hydroxide, potassium hydroxide and organic amine, was added to this solution with heating to 90 t and controlling its pH between 1.4-2.0, then all zirconium existing in the solution were precipitated as basic zirconium sulfate. The amount of sulfuric acid used as a precipitant is preferable 2 molar ratio to 5 moles of zirconium. If the amount is less than 2 moles, the formation yield of basic zirconium sulfate become low and also if it exceed 2 moles, large amount of sulfuric acid cause low pH of the solution and finally result in poor formation yield of 1 o basic zirconium sulfate. If the pH of solution, wherein alkaline solution was added, is less than 1.4, the zirconium components existing in this solution cannot be fully precipitated and remained as ions in the solution, and if it exceed 2.0, all the zirconium components were precipitated but the some components such as silica, titanium and iron were precipitated together and co-existed in the basic zirconium sulfate precipitates.
After filtering the basic zirconium sulfate precipitate, its dispersion solution was made by suspension with water. And if the pH of this solution is controlled between 8-10 with adding some ammonia water or ammonia gas, the basic zirconium sulfate precipitates were tranformed to 20 zirconium hydroxide [ZrO(OH) 2 xH 2 O] precipitates. At this time, if the pH of solution is less than 8, basic zirconium sulfate cannot completely converted to zirconium hydroxide and some residual sulfate group in precipitates cause bad solubility of zirconium hydroxide. And if it exceed 10, it is also undesirable because of the excess use of ammonia.
With filtering zirconium hydroxide precipitates and dissolving in concentrated hydrochloric acid in equivalent ratio of zirconium, aqueous c a 1- -sC i zirconium oxychloride solution free of clacium component was prepared.
And then the resulting solution was evaporated at 90 tC up and hydrochloric acid was added until each concentration of zirconium ions and hydrochloric acid of the solution was controlled between the range of 85-150 g/ I and 150-300 g/ I, respectively. And if it is cooled to room temperature, crystallization was taken place and crystals were seperated from the solution. By filtering with centrifuge, high-purity zirconium oxychloride crystals were recovered. But in the course of concentrating aqueous zirconium oxychloride solution and adding hydrochloric acid, if the concentration of zirconium ions and hydrochloric acid is lower than the above specified range, the yield of crystals becomes very poor.
And if it is higher, the yield is improved but it is undesirable in energy consumption for evaporating much quantity of solution and much impurities were contained in the crystals because the crystallization took place even at high temperature simultaneously with the addition of hydrochloric acid.
As explained in the above, the process for preparing high-purity zirconium oxychloride crystals has advantages that impurities such as 20 sodium compound (sodium chloride), which can be easily co-existed as mixed in oxychloride crystals, was prohibited from the first by making complete decomposition using calcium carbonate as decomposition agent instead of sodium hydroxide or sodium carbonate; most impurities including calcium can be separated and removed by way of intermediate preparing steps, that is, precipitating basic zirconium sulfate and converting it into zirconium hydroxide; and high-purity zirconium oxychloride crystals with high yield can be prepared through only one crystallization process.
This invention can be illustrated in the following Examples but it cannot be limited by the following Examples.
s EXAMPLE 1 After mixing zircon (ZrSiO 4 powder and calcium carbonate in 1:3 molar ratio and molding it to globe shaped pellets having diameter about 1 cm, it was carried out decomposition reaction for 30 minutes in rotary kiln maintained its temperature at 1,350 'c By crushing the said particles and leaching it with 3.5 hydrochloric acid solution, calcium silicate was removed and calcium zirconate powder was prepared. The calcium zirconate (200 g) powder was dissolved in 25 hydrochloric acid solution (600 ml), diluted with distilled water and removed the undissolved components through filtration. To this solution, 95 sulfuric acid (46 g) was added with maintaining its temperature at 90 It for one hour and adjusting its pH at 1.4 with ammonia water, then all the zirconium ions were precipitated as basic zirconium sulfate. Thus prepared precipate o' was filtered and dispersed into distilled water (1 And if the pH of o oo dispersed precipitate slurry was controlled at 8.5 by adding 25% ammonia 20 water, the basic zirconium sulfate precipitate was converted to zirconium hydroxide precipitate. By filtering, water-washing and dissolving said zirconium hydroxide precipitate in 25 hydrochloric acid (300 ml), aqueous zirconium oxychloride aqueous solution was prepared a-d it was concentrated with heating untill its volume to be 450 ml. And then 35 hydrochloric acid (500 ml) was added and its concentration of zirconium ions become 115 g/ I and that of hydrochloric acid becomes 225 g/ I By cooling the solution to room temperature and filtering with centrifuge, zirconium oxychloride crystals (320 g, 89 of yield) was recovered.
EXAMPLE 2 By the same manner as the above Example 1, the acidic solution of calcium zirconate (200 g) was prepared and zirconium oxychloride crystals (315 g) was recovered by the same manner as the above Example 1 except that the pH of solution was adjusted at 2.0 using the 5 M potassium hydroxide solution in the course of precipitating step of basic zirconium sulfate.
EXAMPLE 3 After preparing the acidic solution of calcium zirconate (200 g) by the same manner as the above Example 1, its pH was adjusted at 1.5 using 5 M potassium hydroxide in the basic zirconium sulfate precipitating step and make the contentration of zirconium ions 95 g/ I and that of hydrochloric acid 255 g/ I. The following process was carried out in the same manner with the above Example 1. As the result, zirconium oxychioride crystals (290 g) was recovered.
EXAMPLE 4 After preparing the acidic solution of calcium zirconate (200 g) by 20 the same manner as the above Example 1, its pH was adjusted at 2.0 using potassium hydroxide solution in the basic zirconium sulfate precipitating step and make the contentration of zirconium ions 135 g/ I and that of hydrochloric acid 195 g/ 1. The following process was carried out in the same manner with the above Example 1. As the result, zirconium oxychloride crystals (300 g) was recovered.
COMPARATIVE EXAMPLE 1 (According to the process of Comparative Example 1 in Jap. Kokai, Tokkyo Koho JP 61-215, 217) After decomposition reaction of zircon and sodium hydroxide mixture (1:4 molar ratio), soda silicate (NaSiO,) leached with dtilled s water was removed by filtering. The remained sodium zirconate powder (100 g) was dissolved in 35 hydrochloric acid (200 ml) and solution of zirconium oxychloride and sodium chloride was prepared by removing the undissolved components thrrough filtration. Thus prepared solution was concentrated and cooled j room temperature and then, zirconium 1 oxychloride crystals were formed.
After dissolving the isolated crystals in water(200 ml), 35 hydrochloric acid was added at room temperature until precipitates were formed in the solution. After completely dissolving the precipitate with heating, it was cooled to room temperature until to form crystals. By is filtering the crystals with centrifuge, zirconium oxychloride crystals(116.7 g, 67 of yield) were recovered.
COMPARATIVE EXAMPLE 2 (According to the process of Comparative Example 2 in Jap. Kokai, Tokkyo Koho JP 61-215, 217) a By dissolving sodium zirconate (100 which was formed with 20 baddeleyite(ZrO 2 96 in hydrochloric acid (200 ml) and removing the undissolved ingredients solution of zirconium oxychloride and sodium chloride was prepared. Thus prepared solution was treated with the same manner of the above Comparative Example 1, then zirconium oxychloride crystals (111.5 g, 64 of yield) were recovered.
EXPERIMENTAL EXAMPLE The impurities in zirconium oxychloride crystals which were prepared by above Example 1-4 and Comparative Example 1-2 were analyzed by ICP method. The results were showen in the following Table 1.
o *0000*
S
*00* 0000 0**0 0* 6000
SO
S. S C. S eq p.
S S
S*
Table 1 Division Content Content of Impurities of ZrO 2 Si Ti Fe Al Ca Na Exam. 1 37.4 0.0025 0.0015 0.0001 0.0004 0.0006 0.0005 Exam. 2 37.3 0.0040 0.0030 0.0015 0.0010 0.0012 0.0010 Exam. 3 37.2 0.0015 0.0022 0.0002 0.0006 0.0006 0.0012 Exam, 4 5 0.0034 0.0029 0.0016 0.0009 0,0011 0.0006 Com.Exam.1 37.5 0.0550 0.0135 0.0044 0.0078 0.0012 0.75 Com.Exam.2 37.2 0.009 0.008 0.004 0.002 0.PT 0.36 As shown in the above Table 1, the products prepared with simplified process of this invention show 5-10 times of high-purity in terms of impurity concentration(in case of Na more than 1000 times) more than those of the products which were prepared by the conventional method.
Claims (7)
1. A process for preparing zirconium oxychloride(ZrOCl 2 8H 2 0) crystals from zircon (ZrSiO,), which comprise leaching calcium zirconate (CaZrO 3 with dilute hydrochloric acid, which was formed by pyrogenic decomposition reaction of calcium carbonate and zircon powder; filtering the basic zirconium sulfate precipitates formed by adding sulfuric acid and alkaline solution to said calcium zirconate solution filtering zirconium hydroxide precipitates prepared by dispersing said basic zirconium sulfate in water and adding ammonia; and recovering the zirconium oxychloride crystals formed by steps of evaporating aqueous zirconium oxychloride solution prepared by dissolving said zirconium hydroxide in hydrochloric acid, adding concentrated hydrochloric acid, cooling to room temperature and filtering. I S 20
2. The process for preparing zirconium oxychloride crystals of claim 1, wherein said calcium carbonate in step is used in an A amount of 2-3 molar ratio to 1 mole of zircon.
3. The process for preparing zirconium oxychloride crystals of claim 1 or D wherein said sulfuric acid in-bsvte step is used in an amount of 2 molar ratio to 5 moles of zirconium ions in the solution. I i I 13
4. The process for preparing zirconium oxychloride crystals of any preceding claim, wherein the pH of said alkaline solution in step is controlled between 1.4-2.0 by adding one or more of ammonia, sodium hydroxide or potassium hydroxide.
The process for preparing zirconium oxychloride crystals of any preceding claim, wherein said ammonia in step is added to make the pH of the solution between 8-
6. The process for preparing zirconium oxychloride crystals of any preceding claim, wherein each concentration of zirconium ions and hydrochloric acid of the said aqueous zirconium oxychloride solution mixed with concentrated hydrochloric acid in step is controlled between 85-150 g/L and 150-300 g/L, respectively.
7. A process for preparing zirconium oxychloride 20 [ZrOC2 8H 2 0] crystals from zircon [ZrSiOi] substantially as hereinbefore described with reference to any one of the *ooooO foregoing examples apart from the comparative examples. Dated this 29th day of August, 1997 KOREA RESEARCH INSTITUTE OF CHEMICAL TECHNOLOGY By their Patent Attorneys GRIFFITH HACK 30 Fellows Institute of Patent Attorneys of Australia SH:\Sigrid\Keep\patentB\44413-96,doc 29/08/97 NT il '%QVI ABSTRACTS This invention relates to a process for preparing high-purity zirconium oxychloride crystals, in particular, to an improved process for preparing high-purity zirconium oxychloride(ZrOC12 8HO) crystals through only one crystallization process, which comprises preparing calcium zirconate(CaZrO) by pyrogenic reaction of zircon powder and clacium carbonate; precipitating basic zirconium sulfate by dissolving said clacium zirconate in hydrochloric acid and adding sulfuric acid and alkaline solution to it in order; converting the precipitated basic zirconium sulfate to zirconium hydroxide with ammonia, preparing aqueous zirconium oxychloride solution by dissolving zirconium hydroxide in hydrochloric acid; and evaporating said aqueous zirconium oxychloride solution and adding concentrated hydrochloric add to it; and crystallizing 15 it by cooling to room temperature. Zirconium oxychloride is widely used as raw materials for a mordants and coating agents and high-purity zirconium oxychloride is S" especially used as essentials to zirconia ceramics. A o .e i-i -r
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019950016619A KR0142920B1 (en) | 1995-06-21 | 1995-06-21 | Manufacture of high-purity zirconium oxychloride crystals |
| KR9516619 | 1995-06-21 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU4441396A AU4441396A (en) | 1997-01-09 |
| AU685018B2 true AU685018B2 (en) | 1998-01-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU44413/96A Ceased AU685018B2 (en) | 1995-06-21 | 1996-02-08 | Process for preparing high-purity zirconium oxychloride crystals |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2823070B2 (en) |
| KR (1) | KR0142920B1 (en) |
| CN (1) | CN1045192C (en) |
| AU (1) | AU685018B2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100424353B1 (en) * | 2000-10-06 | 2004-03-24 | 한국과학기술연구원 | Manufacture of Zirconiumoxychloride by Fusion with Lime |
| KR100473399B1 (en) * | 2002-02-01 | 2005-03-08 | 주식회사 엠스 | Process for the preparation of fine ceramic powders |
| CN100343174C (en) * | 2005-05-25 | 2007-10-17 | 宜兴新兴锆业有限公司 | High-purity ultra-fine zirconia production process |
| JP5611382B2 (en) * | 2013-01-25 | 2014-10-22 | Ｄｏｗａハイテック株式会社 | Method for producing stabilized zirconia powder and precursor thereof |
| CN103265072B (en) * | 2013-05-29 | 2016-06-22 | 河南佰利联化学股份有限公司 | A kind of basic zirconium chloride method for crystallising |
| CN103950977B (en) * | 2014-05-15 | 2015-10-21 | 李树昌 | Zirconic method is extracted from containing zirconium solid solution material |
| CN104524797B (en) * | 2014-12-26 | 2016-01-27 | 淄博广通化工有限责任公司 | Energy-conservation concentration and evaporation method in zirconium oxychloride production process |
| CN105502490B (en) * | 2015-04-21 | 2017-03-29 | 江西晶安高科技股份有限公司 | A kind of coarseness, spherical zirconium hydroxide of bigger serface and preparation method thereof |
| CN107365149A (en) * | 2017-09-07 | 2017-11-21 | 张家港市六福新材料科技有限公司 | A kind of preparation method of zirconium oxide magnesia ceramics material |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0334732A1 (en) * | 1988-03-22 | 1989-09-27 | Societe Europeenne Des Produits Refractaires | Novel reactive derivative of zirconium and its preparation |
| JPH0492819A (en) * | 1990-08-06 | 1992-03-25 | Tosoh Corp | Production of high-purity zirconium oxychloride |
| JPH06127944A (en) * | 1992-10-16 | 1994-05-10 | Tosoh Corp | Production of aqueous zirconium chloride solution |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3143921C2 (en) * | 1981-11-05 | 1984-06-28 | Dynamit Nobel Ag, 5210 Troisdorf | Process for the production of basic zirconium carbonate |
| JPH04342419A (en) * | 1990-10-26 | 1992-11-27 | Westinghouse Electric Corp <We> | Method of hydrolyzing group ivb metal chlorides |
-
1995
- 1995-06-21 KR KR1019950016619A patent/KR0142920B1/en not_active IP Right Cessation
-
1996
- 1996-02-08 AU AU44413/96A patent/AU685018B2/en not_active Ceased
- 1996-02-26 JP JP8037811A patent/JP2823070B2/en not_active Expired - Fee Related
- 1996-03-15 CN CN96103606A patent/CN1045192C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0334732A1 (en) * | 1988-03-22 | 1989-09-27 | Societe Europeenne Des Produits Refractaires | Novel reactive derivative of zirconium and its preparation |
| JPH0492819A (en) * | 1990-08-06 | 1992-03-25 | Tosoh Corp | Production of high-purity zirconium oxychloride |
| JPH06127944A (en) * | 1992-10-16 | 1994-05-10 | Tosoh Corp | Production of aqueous zirconium chloride solution |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2823070B2 (en) | 1998-11-11 |
| CN1045192C (en) | 1999-09-22 |
| CN1139074A (en) | 1997-01-01 |
| JPH092819A (en) | 1997-01-07 |
| KR970001226A (en) | 1997-01-21 |
| KR0142920B1 (en) | 1998-07-15 |
| AU4441396A (en) | 1997-01-09 |
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