CA2256134A1 - Process for the preparation of anhydrous sodium sulfide - Google Patents
Process for the preparation of anhydrous sodium sulfide Download PDFInfo
- Publication number
- CA2256134A1 CA2256134A1 CA002256134A CA2256134A CA2256134A1 CA 2256134 A1 CA2256134 A1 CA 2256134A1 CA 002256134 A CA002256134 A CA 002256134A CA 2256134 A CA2256134 A CA 2256134A CA 2256134 A1 CA2256134 A1 CA 2256134A1
- Authority
- CA
- Canada
- Prior art keywords
- sodium sulfide
- water
- drier
- temperature
- anhydrous sodium
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/22—Alkali metal sulfides or polysulfides
- C01B17/38—Dehydration
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Drying Of Solid Materials (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Saccharide Compounds (AREA)
- Paper (AREA)
- Detergent Compositions (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The invention provides a process for the preparation of anhydrous sodium sulfide by heating sodium sulfide having a water content of about 35 to 45 % in a drier under reduced pressure, the temperature of the water-containing sodium sulfide to be dried being increased from approximately 20°C
at the drier inlet to at least about 180°C at its outlet.
Preferably, the apparatus is a contact-type drier, and the sodium sulfide is in a comminuted form, more particularly in the form of scales, lamellae or flakes having an edge length of from 5 to 8 mm. The method can produce anhydrous sodium sulfide having a content of at least about 98% Na2S.
at the drier inlet to at least about 180°C at its outlet.
Preferably, the apparatus is a contact-type drier, and the sodium sulfide is in a comminuted form, more particularly in the form of scales, lamellae or flakes having an edge length of from 5 to 8 mm. The method can produce anhydrous sodium sulfide having a content of at least about 98% Na2S.
Description
CA 022~6134 1998-12-1~
Process For The Preparation Of Anhydrous Sodium Sulfide The invention relates to the preparation of anhydrous sodium sulfide by heating water-containing sodium sulfide under reduced pressure.
Methods for preparing an anhydrous sodium sulfide from Na2S 9H2O, Na2S 6H2O or Na2S 5H2O are already known from the prior art.
According to E.P.O. 345,136, the monohydrate is prepared in the first dehydration step. The elimination of water requires a time of 2 hours or more. The remaining water contained in the monohydrate is then removed at a temperature of from 90 to 200~C and under a reduced pressure of approximately from 2.66 kPa (20 torr) to 66.5 kPa (500 torr).
A similar, two-step method for the preparation of crystalline anhydrous sodium sulfide is described in E.P.O. 361,998.
The disadvantage of these known methods is that it is necessary to wait for the reaction in the first step, for example to the monohydrate, to be complete (E.P.O.
CA 022~6134 1998-12-1~
345,136) before this compound can be conveyed to the second temperature step.
A product that is available commercially is a water-containing sodium sulfide having an Na2S content of from 60 to 62 %. According to stoichiometric calculation, that corresponds approximately to Na2S 3H2O.
The introduction of hydrogen sulfide into concentrated lo sodium hydroxide solution yields, at temperatures above 100~C, a sodium sulfide hydrate melt having a content of approximately from 60 % to 62 % Na2S. The melt is placed on a cooling conveyor, on which it solidifies (T < 90~C).
Comminution generally yields a flaky product, which is then available commercially.
An object of this invention is to provide a method by means of which there is obtained a sodium sulfide that is anhydrous to a greater possible extent.
According to this invention, there is provided a process for the preparation of anhydrous sodium sulfide by heating water-containing sodium sulfide under reduced pressure, in which sodium sulfide having a water content of from 35 to 45 %, is conveyed, with mixing, through an apparatus in which the temperature of the Na2S is raised continuously CA 022~6134 1998-12-1~
from approximately 20~C at the point where the solid sodium sulfide is fed into the apparatus to 2 180~C at the apparatus outlet, while maintaining a low pressure of < 20 torr.
In this manner, undesired melting of the material that is to be dehydrated is minimized.
A pressure of < 11 torr is preferably maintained during lo the dehydration process.
For the process according to the invention contact driers are particularly useful. Contact driers are to be understood as being apparatuses in which the heat from a heating surface is transferred to the solid that is in contact with this surface. Such apparatuses include, for example, paddle driers and plate driers, the former generally being operated discontinuously and the latter continuously.
Plate driers that are installed vertically have proved to be especially suitable. In these apparatuses, the plates, which are arranged from top to bottom, are combined into three or more sets of plates of different temperature zones. The solid temperature in the first set after the point at which the solid is fed in is from 20 to 70~C, and CA 022~6134 1998-12-1~
the solid temperature (product temperature) in front of the solid outlet is greater than 180~C.
The water-containing Na2S is preferably used in the form of scales, lamellae or flakes having an edge length of from 5 to 8 mm.
According to the invention it is possible markedly to reduce the dwell time of the sodium sulfide that is to be lo dehydrated in the drying process as compared with the prior art, and to make available a dehydration process which may be carried out discontinuously and, preferably, continuously.
Where a vacuum plate drier is used in continuous operation, the process can yield an anhydrous sodium sulfide having a content of at least 98 wt.%, and preferably 99 wt.% Na2S, even after dwell times in the drier of 2 90 minutes.
Example A mass flow of from 300 to 400 kg/h of Na2S having a water content of from 38 to 40 wt.% is fed in the form of flakes having an edge length of from 5 to 8 mm into a vacuum plate drier in which a vacuum of < 15 mbar is maintained.
CA 022~6134 1998-12-1~
The crude product passes through the drier in a meandering manner from top to bottom, during which it is heated and gives up the water bound in the form of the hydrateO
The individual heating plates are combined to form three sets of plates, the solid temperature in the uppermost set of plates rising from approximately 20~C to approximately 70~C and the temperature of the solid as it emerges at the solid outlet at the end of the third set being 2 180~C.
o The passage time through the drier is 2 90 minutes.
The starting compounds, or the products that are drying, are regularly rearranged on the plates.
In this manner, a product having a content of more than 99 wt.% Na2S is obtained.
Process For The Preparation Of Anhydrous Sodium Sulfide The invention relates to the preparation of anhydrous sodium sulfide by heating water-containing sodium sulfide under reduced pressure.
Methods for preparing an anhydrous sodium sulfide from Na2S 9H2O, Na2S 6H2O or Na2S 5H2O are already known from the prior art.
According to E.P.O. 345,136, the monohydrate is prepared in the first dehydration step. The elimination of water requires a time of 2 hours or more. The remaining water contained in the monohydrate is then removed at a temperature of from 90 to 200~C and under a reduced pressure of approximately from 2.66 kPa (20 torr) to 66.5 kPa (500 torr).
A similar, two-step method for the preparation of crystalline anhydrous sodium sulfide is described in E.P.O. 361,998.
The disadvantage of these known methods is that it is necessary to wait for the reaction in the first step, for example to the monohydrate, to be complete (E.P.O.
CA 022~6134 1998-12-1~
345,136) before this compound can be conveyed to the second temperature step.
A product that is available commercially is a water-containing sodium sulfide having an Na2S content of from 60 to 62 %. According to stoichiometric calculation, that corresponds approximately to Na2S 3H2O.
The introduction of hydrogen sulfide into concentrated lo sodium hydroxide solution yields, at temperatures above 100~C, a sodium sulfide hydrate melt having a content of approximately from 60 % to 62 % Na2S. The melt is placed on a cooling conveyor, on which it solidifies (T < 90~C).
Comminution generally yields a flaky product, which is then available commercially.
An object of this invention is to provide a method by means of which there is obtained a sodium sulfide that is anhydrous to a greater possible extent.
According to this invention, there is provided a process for the preparation of anhydrous sodium sulfide by heating water-containing sodium sulfide under reduced pressure, in which sodium sulfide having a water content of from 35 to 45 %, is conveyed, with mixing, through an apparatus in which the temperature of the Na2S is raised continuously CA 022~6134 1998-12-1~
from approximately 20~C at the point where the solid sodium sulfide is fed into the apparatus to 2 180~C at the apparatus outlet, while maintaining a low pressure of < 20 torr.
In this manner, undesired melting of the material that is to be dehydrated is minimized.
A pressure of < 11 torr is preferably maintained during lo the dehydration process.
For the process according to the invention contact driers are particularly useful. Contact driers are to be understood as being apparatuses in which the heat from a heating surface is transferred to the solid that is in contact with this surface. Such apparatuses include, for example, paddle driers and plate driers, the former generally being operated discontinuously and the latter continuously.
Plate driers that are installed vertically have proved to be especially suitable. In these apparatuses, the plates, which are arranged from top to bottom, are combined into three or more sets of plates of different temperature zones. The solid temperature in the first set after the point at which the solid is fed in is from 20 to 70~C, and CA 022~6134 1998-12-1~
the solid temperature (product temperature) in front of the solid outlet is greater than 180~C.
The water-containing Na2S is preferably used in the form of scales, lamellae or flakes having an edge length of from 5 to 8 mm.
According to the invention it is possible markedly to reduce the dwell time of the sodium sulfide that is to be lo dehydrated in the drying process as compared with the prior art, and to make available a dehydration process which may be carried out discontinuously and, preferably, continuously.
Where a vacuum plate drier is used in continuous operation, the process can yield an anhydrous sodium sulfide having a content of at least 98 wt.%, and preferably 99 wt.% Na2S, even after dwell times in the drier of 2 90 minutes.
Example A mass flow of from 300 to 400 kg/h of Na2S having a water content of from 38 to 40 wt.% is fed in the form of flakes having an edge length of from 5 to 8 mm into a vacuum plate drier in which a vacuum of < 15 mbar is maintained.
CA 022~6134 1998-12-1~
The crude product passes through the drier in a meandering manner from top to bottom, during which it is heated and gives up the water bound in the form of the hydrateO
The individual heating plates are combined to form three sets of plates, the solid temperature in the uppermost set of plates rising from approximately 20~C to approximately 70~C and the temperature of the solid as it emerges at the solid outlet at the end of the third set being 2 180~C.
o The passage time through the drier is 2 90 minutes.
The starting compounds, or the products that are drying, are regularly rearranged on the plates.
In this manner, a product having a content of more than 99 wt.% Na2S is obtained.
Claims (12)
1. A method for the preparation of anhydrous sodium sulfide by heating water-containing sodium sulfide under reduced pressure, in which sodium sulfide having a water content of from 35 to 45 % is conveyed, with mixing, through an apparatus in which the temperature of the sodium sulfide is raised continuously from approximately 20°C at the point where the solid sodium sulfide is fed into the apparatus to ~ 180°C at the apparatus outlet, while maintaining a low pressure of < 20 torr.
2. A method according to claim 1, wherein a pressure of < 11 torr is maintained during conveyance of the sodium sulfide through the apparatus.
3. A method according to claim 1 or 2, in which the water-containing sodium sulfide is in comminuted form.
4. A method according to claim 3, wherein the water-containing sodium sulfide is in the form of scales, lamellae or flakes having an edge length of from 5 to 8 mm.
5. A method according to any one of claims 1 to 4, in which the water-containing sodium sulfide is resident in the apparatus for a time sufficient to provide at the outlet an anhydrous sodium sulfide having a content of at least 98 wt.% Na2S.
6. A method according to claim 5, in which the anhydrous sodium sulfide is about 99 wt.% Na2S.
7. A method according to any one of claims 1 to 6, in which a contact drier is used as the apparatus.
8. A method according to claim 7, in which the apparatus is a paddle drier.
9. A method according to claim 7, in which the apparatus is a plate drier.
10. A method according to claim 9, in which the plates of the plate drier are combined into sets which provide three or more temperature zones such that the temperature of the sodium sulfide in the first zone after feeding is from 20 to 70°C, and its temperature just before the apparatus outlet is greater than about 180°C.
11. A method according to claim 9 or 10, carried out with a continuous conveyance of sodium sulfide through the apparatus.
12. A method according to claim 8, in which the sodium sulfide dehydration is carried out discontinuously.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19755760A DE19755760A1 (en) | 1997-12-16 | 1997-12-16 | Process for the preparation of anhydrous sodium sulfide |
| DE19755760.0 | 1997-12-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2256134A1 true CA2256134A1 (en) | 1999-06-16 |
Family
ID=7852013
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002256134A Abandoned CA2256134A1 (en) | 1997-12-16 | 1998-12-15 | Process for the preparation of anhydrous sodium sulfide |
Country Status (20)
| Country | Link |
|---|---|
| EP (1) | EP0924165B1 (en) |
| JP (1) | JP4528375B2 (en) |
| KR (1) | KR100572814B1 (en) |
| CN (1) | CN1116224C (en) |
| AT (1) | ATE243164T1 (en) |
| BR (1) | BR9805267A (en) |
| CA (1) | CA2256134A1 (en) |
| CZ (1) | CZ404598A3 (en) |
| DE (2) | DE19755760A1 (en) |
| DK (1) | DK0924165T3 (en) |
| ES (1) | ES2198636T3 (en) |
| ID (1) | ID21469A (en) |
| IL (1) | IL127554A (en) |
| PL (1) | PL193298B1 (en) |
| PT (1) | PT924165E (en) |
| RU (1) | RU2201891C2 (en) |
| SK (1) | SK170398A3 (en) |
| TR (1) | TR199802601A2 (en) |
| TW (1) | TW521064B (en) |
| ZA (1) | ZA9811463B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19930495C1 (en) * | 1999-07-01 | 2000-11-09 | Degussa | Alkoxysilylalkylpolysulfide compounds, useful assistants in the production of silica filled rubber, made by reacting silyl alkyl halides with alkali polysulfides obtained by reacting alkali hydroxides with sulfur in non-aqueous solvent |
| WO2001025146A2 (en) * | 1999-10-05 | 2001-04-12 | Ppg Industries Ohio, Inc. | Method of preparing anhydrous alkali metal sulfides |
| DE19956377A1 (en) * | 1999-11-24 | 2001-06-13 | Degussa | Process for the production of anhydrous, high-purity sodium sulfide |
| US6582675B2 (en) * | 2000-03-28 | 2003-06-24 | Degussa Ag | Method for the preparation of anhydrous sodium sulfide |
| DE10256531A1 (en) | 2002-12-04 | 2004-06-24 | Degussa Ag | Process for the preparation of anhydrous alkali sulfide |
| CN104163402A (en) * | 2014-07-18 | 2014-11-26 | 中国石油化工股份有限公司 | Preparation method of anhydrous sodium sulfide |
| CN106076504A (en) * | 2016-08-25 | 2016-11-09 | 广西联壮科技股份有限公司 | The reducing mechanism of sodium sulfide raw material pretreatment stage |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58175751A (en) * | 1982-04-08 | 1983-10-15 | Hitachi Zosen Corp | Drying method by means of chemical heat accumulation |
| JPH0251404A (en) * | 1988-05-31 | 1990-02-21 | Sankyo Kasei Kk | Production of anhydrous sodium sulfide crystal |
| JPH0259406A (en) * | 1988-08-25 | 1990-02-28 | Sankyo Kasei Kk | Production of anhydrous sodium sulfide crystal |
| JPH04310508A (en) * | 1991-04-03 | 1992-11-02 | Sankyo Kasei Kk | Production of sodium sulfide low-hydrate or anhydride |
| JP3437206B2 (en) * | 1993-02-23 | 2003-08-18 | ナガオ株式会社 | Dehydration method of sodium sulfide |
| JP3408570B2 (en) * | 1993-03-02 | 2003-05-19 | ナガオ株式会社 | Dehydration method of tangible sodium hydrosulfide |
| JPH06256003A (en) * | 1993-03-02 | 1994-09-13 | Nagao Kk | Production of formed material of highly concentrated sodium hydrosulfide |
| JP3408575B2 (en) * | 1993-04-13 | 2003-05-19 | ナガオ株式会社 | Dehydration method of tangible sodium hydrosulfide with inert gas |
| JP3408576B2 (en) * | 1993-04-22 | 2003-05-19 | ナガオ株式会社 | Method for dehydrating tangible sodium sulfide with inert gas |
-
1997
- 1997-12-16 DE DE19755760A patent/DE19755760A1/en not_active Withdrawn
-
1998
- 1998-11-27 ES ES98122604T patent/ES2198636T3/en not_active Expired - Lifetime
- 1998-11-27 DK DK98122604T patent/DK0924165T3/en active
- 1998-11-27 AT AT98122604T patent/ATE243164T1/en not_active IP Right Cessation
- 1998-11-27 EP EP98122604A patent/EP0924165B1/en not_active Expired - Lifetime
- 1998-11-27 DE DE59808752T patent/DE59808752D1/en not_active Expired - Fee Related
- 1998-11-27 PT PT98122604T patent/PT924165E/en unknown
- 1998-12-09 CZ CZ984045A patent/CZ404598A3/en unknown
- 1998-12-11 SK SK1703-98A patent/SK170398A3/en unknown
- 1998-12-11 KR KR1019980054311A patent/KR100572814B1/en not_active IP Right Cessation
- 1998-12-14 TW TW087121005A patent/TW521064B/en not_active IP Right Cessation
- 1998-12-14 JP JP35468098A patent/JP4528375B2/en not_active Expired - Fee Related
- 1998-12-14 ZA ZA9811463A patent/ZA9811463B/en unknown
- 1998-12-14 ID IDP981623A patent/ID21469A/en unknown
- 1998-12-14 IL IL12755498A patent/IL127554A/en not_active IP Right Cessation
- 1998-12-15 BR BR9805267-5A patent/BR9805267A/en not_active IP Right Cessation
- 1998-12-15 CA CA002256134A patent/CA2256134A1/en not_active Abandoned
- 1998-12-15 TR TR1998/02601A patent/TR199802601A2/en unknown
- 1998-12-15 PL PL330303A patent/PL193298B1/en not_active IP Right Cessation
- 1998-12-16 CN CN98125565A patent/CN1116224C/en not_active Expired - Fee Related
- 1998-12-16 RU RU98123003/12A patent/RU2201891C2/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| CZ404598A3 (en) | 1999-11-17 |
| ATE243164T1 (en) | 2003-07-15 |
| DE19755760A1 (en) | 1999-06-24 |
| SK170398A3 (en) | 1999-12-10 |
| IL127554A0 (en) | 1999-10-28 |
| DE59808752D1 (en) | 2003-07-24 |
| PL330303A1 (en) | 1999-06-21 |
| JPH11236204A (en) | 1999-08-31 |
| JP4528375B2 (en) | 2010-08-18 |
| ES2198636T3 (en) | 2004-02-01 |
| PT924165E (en) | 2003-11-28 |
| KR100572814B1 (en) | 2006-09-20 |
| PL193298B1 (en) | 2007-01-31 |
| EP0924165B1 (en) | 2003-06-18 |
| ZA9811463B (en) | 1999-06-14 |
| IL127554A (en) | 2001-08-08 |
| TR199802601A3 (en) | 1999-07-21 |
| TR199802601A2 (en) | 1999-07-21 |
| DK0924165T3 (en) | 2003-10-06 |
| BR9805267A (en) | 1999-11-09 |
| EP0924165A1 (en) | 1999-06-23 |
| TW521064B (en) | 2003-02-21 |
| KR19990062979A (en) | 1999-07-26 |
| CN1116224C (en) | 2003-07-30 |
| ID21469A (en) | 1999-06-17 |
| RU2201891C2 (en) | 2003-04-10 |
| CN1220233A (en) | 1999-06-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |