CA2032768C - Process for the removal of sodium polysulphide from run-down sodium/sulphur batteries - Google Patents
Process for the removal of sodium polysulphide from run-down sodium/sulphur batteriesInfo
- Publication number
- CA2032768C CA2032768C CA 2032768 CA2032768A CA2032768C CA 2032768 C CA2032768 C CA 2032768C CA 2032768 CA2032768 CA 2032768 CA 2032768 A CA2032768 A CA 2032768A CA 2032768 C CA2032768 C CA 2032768C
- Authority
- CA
- Canada
- Prior art keywords
- sodium
- sulphur
- solution
- scrap
- batteries
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/54—Reclaiming serviceable parts of waste accumulators
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/84—Recycling of batteries or fuel cells
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
- Catalysts (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
In a process for the removal of sodium polysulphide from run-down sodium/sulphur batteries, the cells are crushed while taking safety measures. The scrap metal is treated in a sodium cyanide solution and on separating the insoluble components the solution obtained is treated with air in the presence of manganese dioxide. The solution then contains sodium thiocyanate and sodium hydroxide. The latter can be reacted with CO2Na2CO3, precipitated and separated out.
Description
The present invention relates to a process for the removal of sodium polysulphide from run-down sodium/sulphur batteries while permitting the recovery of an alkaline sodium thiocyanate solution. Sodium thiocyanate is used, for example, in the chemical and pharmaceutical industries for the production of organic thio-cyanates, isothiocyanates, mustard oils, pesticides, biocides, in the photo industry for toning, sensitizing and stabilizing and for the production of gloss-forming agents in galvanotechnics.
No process for the removal of sodium polysulphide from Na/S batteries while simultaneously recovering sodium thiocyanates is known from the literature.
It is an object of the present invention to remove sodium polysulphide from run-down sodium/sulphur batteries while recovering assets, namely, sodium thiocyanate in the form of an alkaline or soda-alkaline solution.
According to a first aspect of the invention there is provided a process for the removal of sodium polysulphide from run-down sodium/sulphur batteries while permitting the recovery of an alkaline sodium thiocyanate solution comprising mechanically crushing batteries or cell sets removed from battery boxes and containing sodium polysulphide and possibly sodium residues to a finely divided scrap having a grain diameter of up to 30 mm, treating the scrap with an aqueous sodium cyanide solution whose cyanide content is in a molar ratio the total sulphur consisting of S0 or S 2, such as 1:1, while stirring, separating the insoluble components of the scrap from the solution, mixing the solution with 0.1 to 20% by weight of manganese dioxide relative to the total sulphur as catalyst, and selectively oxidizing the sulphidic sulphur by passing air through at temperatures ranging from room temperature to 110C for the intermediate formation of elementary sulphur, and concluding the reaction of said 20327~8 sulphur with the residual sodium cyanide to sodium thiocyanate.
Important steps of this method thus are as follows:
shredding the run-down batteries to finely divided scrap, feeding the scrap into an aqueous sodium cyanide solution and reacting while utilizing the heat of reaction, separating the non-reacting components, selectively oxidizing the sulphidic sulphur to elementary sulphur, followed by an in-situ reaction with free sodium cyanide to sodium thiocyanate. The selective oxidation of the sulphidic sulphur in the presence of manganese dioxide and the use of air as oxidizing agent are particularly important.
According to a further aspect of the invention there is provided a process for the removal of sodium polysulphide from run-down sodium/sulphur batteries while permitting the recovery of an alkaline sodium thiocyanate solution, comprising mechanically crushing the batteries or cell setsremoved from battery boxes and containing sodium polysulphide and possibly sodium residues to a finely divided scrap having a grain diameter of up to 30 mm, mixing while stirring an aqueous sodium cyanide solution whose cyanide content is in a molar ratio to the total sulphur present, consisting of S0 or S 2, such as 1:1, with 0.1 to 20% by weight of manganese dioxide relative to the total sulphur, selectively oxidizing the sulphidic sulphur by passing air through at temperatures ranging from room temperature to 110C for the intermediate formation of elementary sulphu, concluding the reaction of said sulphur with residual sodium cyanide to sodium thiocyanate, and separating the insoluble components from the aqueous solution of the sodium thiocyanate product.
In this slightly modified process sodium cyanide solution is mixed with the scrap and the catalyst while stirring and is allowed to react, whereupon the oxidation with air is carried out. Finally the insoluble substances are removed from the solution of the sodium thiocyanate formed.
In the process according to the two alternatives aqueous sodium cyanide solutions having a content of 15 to 35% by weight are applied. The concentration preferably is 20 to 30~ by weight.
In the two alternatives the reaction of the polysulphide with the cyanide is exothermic. It has been found that it is favourable to reheat to the boiling temperature. In order to carry out the reaction of the formally nonvalent sulphur with the sodium cyanide quantitatively, it is advantageous to maintain a postreaction time of 1 to 40, preferably 5 to 30 minutes at reflux temperature. On completion of the reaction of this sulphur portion, the sulphidic sulphur is selectively oxidized to sulphur by passing air through the reaction mixture in the presence of the catalyst, whereupon it is reacted in situ with free sodium cyanide to sodium thiocyanate.
For the two methods a number of favourable variants are equally applicable; they will be described hereafter:
It has been found that it is favourable when the mechanical comminution of the batteries or of the cell sets is carried out under an atmosphere of water vapour or inert gas.
The batteries or the cell sets are preferably crushed to scrap having a grain diameter < 10 mm.
In order to intensify the action of the sodium cyanide solution on the scrap, the scrap can be treated with said 20~2768 solution, or when proceeding according to the second alternative, the scrap can be treated with said solution in the presence of a catalyst while reheating to the boiling temperature.
Within the total range of the applicable catalyst concentration the application of 2 to 7% by weight of catalyst, relative to the total sulphur, has proved to be particularly suitable.
For the selective oxidation of the sulphidic sulphur the lo turbulent motion caused by the injection of air into the reactor filling usually is sufficient. However, it is even better when the reaction mixture is stirred while the air is passing through.
The selective oxidation of the sulphidic sulphur can be carried out most easily at temperatures of 50 to 80C.
The product solution which contains the sodium thiocyanate and can be obtained by means of the two methods according to the present invention is alkaline because of its content of sodium hydroxides. According to a favourable embodiment of the present invention the alkaline reaction can be reduced in that the sodium hydroxide contained in the solution of the sodium thiocyanate product is converted into sodium carbonate by passing carbon dioxide through or injecting it and that the carbonate precipitated in the form of solids or by cooling is removed from the product solution which then is alkaline with soda. This can be done by means of filtration.
When operating according to the present invention yields of up to 98.7% relative to the total sulphur are obtained.
The present invention will be described in more detail by means of the following examples:
Example 1 2.50 g (7 moles) of a 98% sodium cyanide are dissolved in 1150 g of water in a three-necked flask provided with agitator, reflux condenser, thermometer and lockable inlet pipe. 353 g (7 moles) of scrap shredded beforehand from cell sets in an atmosphere of water vapour and having a total sulphur content of 63.6 % by weight are rapidly added while stirring. Because of the exothermic reaction the temperature increases from 25C to 95C. The reaction mixture is further heated to the boiling temperature (110C) and stirred for 20 minutes. The reaction mixtures is exactly filtered with suction by means of a tin strip filter and transferred into a glass tube having a frit fused at the bottom, mixed with 45 g of manganese dioxide (MnO2) and heated to 65C, whereupon 424 standard litres of air (3.98 moles of 2) are passed through from below. Upon cooling to room temperature 44.8 standard litres (2 moles) of carbon dioxide are passed through the reaction solution from below while the pH value decreases from pH 13.9 to pH 8Ø The precipitated deposit is filtered with suction. The filtrate contains 6.91 moles of sodium thiocyanate, i.e., a yield of 98,7%.
Example 2 150 g (3 moles) of a 98% sodium cyanide are dissolved in 550 g of water in a three-necked flask provided with agitator, reflux condenser, thermometer and lockable inlet pipe. 250 g (3 moles) of shredded cell material having a total sulphur content of 38.4% by weight are rapidly added, while stirring. Because of the exothermic reaction the temperature increases from room temperature to 93C. Heating is contained up to the boiling temperature (110C), followed by stirring at this temperature for 7 minutes, whereupon 0.096 g of manganese dioxide (MnO2) are added. A glass tube having a frit fused at the bottom is inserted in the reaction mixture. At 110C 200 standard litres of air (1.88 moles of 2) are passed through this tube into the reaction mixture.
S The hot reaction mixtures is exactly filtered with suction, cooled to room temperature and filled into a glass tube having a frit that is fused at the bottom. 22.4 standard litres (1 moles) of carbon dioxide are then passed through the solution from below. At the same time the pH value decreases from pH 13.0 to pH 8Ø The precipitated deposit is filtered with suction. The solution contains 2.79 moles of sodium thiocyanate, i.e., a yield of 93.1%.
No process for the removal of sodium polysulphide from Na/S batteries while simultaneously recovering sodium thiocyanates is known from the literature.
It is an object of the present invention to remove sodium polysulphide from run-down sodium/sulphur batteries while recovering assets, namely, sodium thiocyanate in the form of an alkaline or soda-alkaline solution.
According to a first aspect of the invention there is provided a process for the removal of sodium polysulphide from run-down sodium/sulphur batteries while permitting the recovery of an alkaline sodium thiocyanate solution comprising mechanically crushing batteries or cell sets removed from battery boxes and containing sodium polysulphide and possibly sodium residues to a finely divided scrap having a grain diameter of up to 30 mm, treating the scrap with an aqueous sodium cyanide solution whose cyanide content is in a molar ratio the total sulphur consisting of S0 or S 2, such as 1:1, while stirring, separating the insoluble components of the scrap from the solution, mixing the solution with 0.1 to 20% by weight of manganese dioxide relative to the total sulphur as catalyst, and selectively oxidizing the sulphidic sulphur by passing air through at temperatures ranging from room temperature to 110C for the intermediate formation of elementary sulphur, and concluding the reaction of said 20327~8 sulphur with the residual sodium cyanide to sodium thiocyanate.
Important steps of this method thus are as follows:
shredding the run-down batteries to finely divided scrap, feeding the scrap into an aqueous sodium cyanide solution and reacting while utilizing the heat of reaction, separating the non-reacting components, selectively oxidizing the sulphidic sulphur to elementary sulphur, followed by an in-situ reaction with free sodium cyanide to sodium thiocyanate. The selective oxidation of the sulphidic sulphur in the presence of manganese dioxide and the use of air as oxidizing agent are particularly important.
According to a further aspect of the invention there is provided a process for the removal of sodium polysulphide from run-down sodium/sulphur batteries while permitting the recovery of an alkaline sodium thiocyanate solution, comprising mechanically crushing the batteries or cell setsremoved from battery boxes and containing sodium polysulphide and possibly sodium residues to a finely divided scrap having a grain diameter of up to 30 mm, mixing while stirring an aqueous sodium cyanide solution whose cyanide content is in a molar ratio to the total sulphur present, consisting of S0 or S 2, such as 1:1, with 0.1 to 20% by weight of manganese dioxide relative to the total sulphur, selectively oxidizing the sulphidic sulphur by passing air through at temperatures ranging from room temperature to 110C for the intermediate formation of elementary sulphu, concluding the reaction of said sulphur with residual sodium cyanide to sodium thiocyanate, and separating the insoluble components from the aqueous solution of the sodium thiocyanate product.
In this slightly modified process sodium cyanide solution is mixed with the scrap and the catalyst while stirring and is allowed to react, whereupon the oxidation with air is carried out. Finally the insoluble substances are removed from the solution of the sodium thiocyanate formed.
In the process according to the two alternatives aqueous sodium cyanide solutions having a content of 15 to 35% by weight are applied. The concentration preferably is 20 to 30~ by weight.
In the two alternatives the reaction of the polysulphide with the cyanide is exothermic. It has been found that it is favourable to reheat to the boiling temperature. In order to carry out the reaction of the formally nonvalent sulphur with the sodium cyanide quantitatively, it is advantageous to maintain a postreaction time of 1 to 40, preferably 5 to 30 minutes at reflux temperature. On completion of the reaction of this sulphur portion, the sulphidic sulphur is selectively oxidized to sulphur by passing air through the reaction mixture in the presence of the catalyst, whereupon it is reacted in situ with free sodium cyanide to sodium thiocyanate.
For the two methods a number of favourable variants are equally applicable; they will be described hereafter:
It has been found that it is favourable when the mechanical comminution of the batteries or of the cell sets is carried out under an atmosphere of water vapour or inert gas.
The batteries or the cell sets are preferably crushed to scrap having a grain diameter < 10 mm.
In order to intensify the action of the sodium cyanide solution on the scrap, the scrap can be treated with said 20~2768 solution, or when proceeding according to the second alternative, the scrap can be treated with said solution in the presence of a catalyst while reheating to the boiling temperature.
Within the total range of the applicable catalyst concentration the application of 2 to 7% by weight of catalyst, relative to the total sulphur, has proved to be particularly suitable.
For the selective oxidation of the sulphidic sulphur the lo turbulent motion caused by the injection of air into the reactor filling usually is sufficient. However, it is even better when the reaction mixture is stirred while the air is passing through.
The selective oxidation of the sulphidic sulphur can be carried out most easily at temperatures of 50 to 80C.
The product solution which contains the sodium thiocyanate and can be obtained by means of the two methods according to the present invention is alkaline because of its content of sodium hydroxides. According to a favourable embodiment of the present invention the alkaline reaction can be reduced in that the sodium hydroxide contained in the solution of the sodium thiocyanate product is converted into sodium carbonate by passing carbon dioxide through or injecting it and that the carbonate precipitated in the form of solids or by cooling is removed from the product solution which then is alkaline with soda. This can be done by means of filtration.
When operating according to the present invention yields of up to 98.7% relative to the total sulphur are obtained.
The present invention will be described in more detail by means of the following examples:
Example 1 2.50 g (7 moles) of a 98% sodium cyanide are dissolved in 1150 g of water in a three-necked flask provided with agitator, reflux condenser, thermometer and lockable inlet pipe. 353 g (7 moles) of scrap shredded beforehand from cell sets in an atmosphere of water vapour and having a total sulphur content of 63.6 % by weight are rapidly added while stirring. Because of the exothermic reaction the temperature increases from 25C to 95C. The reaction mixture is further heated to the boiling temperature (110C) and stirred for 20 minutes. The reaction mixtures is exactly filtered with suction by means of a tin strip filter and transferred into a glass tube having a frit fused at the bottom, mixed with 45 g of manganese dioxide (MnO2) and heated to 65C, whereupon 424 standard litres of air (3.98 moles of 2) are passed through from below. Upon cooling to room temperature 44.8 standard litres (2 moles) of carbon dioxide are passed through the reaction solution from below while the pH value decreases from pH 13.9 to pH 8Ø The precipitated deposit is filtered with suction. The filtrate contains 6.91 moles of sodium thiocyanate, i.e., a yield of 98,7%.
Example 2 150 g (3 moles) of a 98% sodium cyanide are dissolved in 550 g of water in a three-necked flask provided with agitator, reflux condenser, thermometer and lockable inlet pipe. 250 g (3 moles) of shredded cell material having a total sulphur content of 38.4% by weight are rapidly added, while stirring. Because of the exothermic reaction the temperature increases from room temperature to 93C. Heating is contained up to the boiling temperature (110C), followed by stirring at this temperature for 7 minutes, whereupon 0.096 g of manganese dioxide (MnO2) are added. A glass tube having a frit fused at the bottom is inserted in the reaction mixture. At 110C 200 standard litres of air (1.88 moles of 2) are passed through this tube into the reaction mixture.
S The hot reaction mixtures is exactly filtered with suction, cooled to room temperature and filled into a glass tube having a frit that is fused at the bottom. 22.4 standard litres (1 moles) of carbon dioxide are then passed through the solution from below. At the same time the pH value decreases from pH 13.0 to pH 8Ø The precipitated deposit is filtered with suction. The solution contains 2.79 moles of sodium thiocyanate, i.e., a yield of 93.1%.
Claims (9)
1. A process for the removal of sodium polysulphide from run-down sodium/sulphur batteries while permitting the recovery of an alkaline sodium thiocyanate solution, comprising mechanically crushing the batteries or cell sets taken from battery boxes and containing sodium polysulphide and optionally sodium residues to a finely divided scrap having a grain size of up to 30 mm, treating the scrap with an aqueous sodium cyanide solution whose cyanide content is in a molar ratio to the total sulphur present, consisting of S0 or S-2, of about 1:1, while stirring, separating the insoluble components of the scrap from the solution, mixing the solution with 0.1 to 20% by weight of manganese dioxide relative to the total sulphur as catalyst, and selectively oxidizing the sulphidic sulphur by passing air through at temperatures ranging from room temperature to 110°C for the intermediate formation of elementary sulphur and concluding the latter's reaction with the residual sodium cyanide present to sodium thiocyanate.
2. A process for the removal of sodium polysulphide from run-down sodium/sulphur batteries while permitting recovery of an alkaline sodium thiocyanate solution, comprising mechanically crushing batteries or cell sets removed from battery boxes and containing sodium polysulphide and optionally sodium residues to a finely divided scrap having a grain diameters of up to 30 mm, mixing an aqueous sodium cyanide solution whose cyanide content is in a molar ratio to the total sulphur present, consisting of S° or S-2, of about 1:1, with the scrap while stirring, with 0.1 to 20% by weight of manganese dioxide relative to the total sulphur as catalyst, selectively oxidizing the sulphidic sulphur by passing air through at temperatures ranging from room temperature to 110°C for the intermediate formation of elementary sulphur, concluding the latter's reaction with the residual sodium cyanide to sodium thiocyanate, and separating the unsoluble compounds from the aqueous solution of the sodium thiocyanate product.
3. A process as claimed in claim 1 or 2, wherein the batteries or cell sets are mechanically comminuted under an atmosphere of water vapour or inert gas.
4. A process as claimed in claim 1 or 2, wherein the batteries or cell sets are crushed to scrap having a grain diameter < 10 mm.
5. A process as claimed in claim 1 or 2, wherein the scrap is treated with the sodium cyanide solution or, when following the procedure defined in claim 2, the scrap is treated with said solution in the presence of the catalyst while reheating to the boiling temperature.
6. A process as claimed in claim 1 or 2, wherein 2 to
7% by weight of catalyst, relative to the total sulphur, are used.
7. A process as claimed in claim 1 or 2, wherein the reaction mixture is stirred while air is passed through.
7. A process as claimed in claim 1 or 2, wherein the reaction mixture is stirred while air is passed through.
8. A process as claimed in claim 1 or 2, wherein the selective oxidation of the sulphidic sulphur is carried out at 50 to 80°C.
9. A process as claimed in claim 1 or 2, wherein the sodium hydroxide contained in the solution of the sodium thiocyanate product is converted into sodium carbonate by passing carbon dioxide through or by injecting it, whereupon the carbonate deposited in the form of solids or precipitated by cooling is removed from the solution, which then is made alkaline with soda.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3942516.9-45 | 1989-12-22 | ||
| DE19893942516 DE3942516C1 (en) | 1989-12-22 | 1989-12-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2032768A1 CA2032768A1 (en) | 1991-06-23 |
| CA2032768C true CA2032768C (en) | 1997-07-01 |
Family
ID=6396165
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2032768 Expired - Fee Related CA2032768C (en) | 1989-12-22 | 1990-12-20 | Process for the removal of sodium polysulphide from run-down sodium/sulphur batteries |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5055283A (en) |
| EP (1) | EP0433654B1 (en) |
| JP (1) | JPH03203173A (en) |
| CA (1) | CA2032768C (en) |
| DE (2) | DE3942516C1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4224884A1 (en) * | 1992-07-28 | 1994-02-03 | Batenus Gmbh & Co Kg | Process for the recovery of raw materials from pre-sorted, used goods, in particular from used electrochemical batteries and accumulators |
| DE4227511C1 (en) * | 1992-08-20 | 1993-07-22 | Silent Power Gmbh, 4300 Essen, De | |
| JP2741834B2 (en) * | 1993-03-24 | 1998-04-22 | 日本碍子株式会社 | Method and apparatus for treating sodium-sulfur battery |
| DE19856071A1 (en) * | 1998-12-04 | 2000-06-15 | Degussa | Process for avoiding water contamination with non-resident organisms |
| CN103373734B (en) * | 2013-07-18 | 2015-07-15 | 江苏燎原环保科技股份有限公司 | Method for preparing high-quality potassium rhodanide by using coke oven gas waste liquor with sulfur and cyanogen removed |
| JP6476598B2 (en) * | 2014-06-03 | 2019-03-06 | 三菱マテリアル株式会社 | Method for recovering sodium from sodium-sulfur battery, apparatus for recovering sodium from sodium-sulfur battery |
| KR102576614B1 (en) * | 2021-05-17 | 2023-09-07 | 목포대학교산학협력단 | Method for recovering valuable metals from waste lithium ion batteries |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3459498A (en) * | 1965-05-07 | 1969-08-05 | Jefferson Chem Co Inc | Conversion of cyanates to thiocyanates |
| US4024229A (en) * | 1970-11-06 | 1977-05-17 | The Mead Corporation | Production of polysulfide with PTFE coated catalyst |
| US4290192A (en) * | 1979-12-20 | 1981-09-22 | Ford Motor Company | Method of making a sodium sulfur battery |
| DE3000563A1 (en) * | 1980-01-09 | 1981-07-16 | Basf Ag, 6700 Ludwigshafen | METHOD FOR DETOXIFYING CYANIDE-CONTAINING REACTION SOLUTIONS AND SEWAGE |
| FI65807C (en) * | 1980-04-16 | 1984-07-10 | Outokumpu Oy | REFERENCE TO A SULFID CONCENTRATION |
| DE3101369C2 (en) * | 1981-01-17 | 1987-01-08 | Klöckner-Humboldt-Deutz AG, 5000 Köln | Process for smelting fine-grained sulphidic copper ore concentrate |
| US4508683A (en) * | 1982-03-15 | 1985-04-02 | Doll Brian E | Control of cyanides in FCC reactor by injection of ammonium polysulfide |
| NL8303659A (en) * | 1982-11-11 | 1984-06-01 | Kloeckner Humboldt Deutz Ag | METHOD FOR WINNING ZINC. |
| FI68661C (en) * | 1983-10-27 | 1985-10-10 | Rm Metal Consulting Ky | FOERFARANDE FOER RAFFINERING AV SULFIDKONCENTRAT INNEHAOLLANDEARSENIK ANTIMON OCH VISMUT |
| CA1307652C (en) * | 1986-05-13 | 1992-09-22 | Iron Otto Simek | Mte sulphur recovery process |
| US4719019A (en) * | 1986-12-10 | 1988-01-12 | Srini Vasan | Treatment of thiocyanate containing waste liquor |
| US4977044A (en) * | 1989-10-03 | 1990-12-11 | Hughes Aircraft Company | Sodium-sulfur thermal battery |
-
1989
- 1989-12-22 DE DE19893942516 patent/DE3942516C1/de not_active Expired - Lifetime
-
1990
- 1990-11-14 EP EP19900121761 patent/EP0433654B1/en not_active Expired - Lifetime
- 1990-11-14 DE DE9090121761T patent/DE59001792D1/en not_active Expired - Fee Related
- 1990-11-22 JP JP2315671A patent/JPH03203173A/en active Pending
- 1990-12-14 US US07/627,820 patent/US5055283A/en not_active Expired - Fee Related
- 1990-12-20 CA CA 2032768 patent/CA2032768C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2032768A1 (en) | 1991-06-23 |
| US5055283A (en) | 1991-10-08 |
| EP0433654A2 (en) | 1991-06-26 |
| DE59001792D1 (en) | 1993-07-22 |
| JPH03203173A (en) | 1991-09-04 |
| EP0433654B1 (en) | 1993-06-16 |
| EP0433654A3 (en) | 1991-12-18 |
| DE3942516C1 (en) | 1991-08-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |