CN101693556A - Process for preparing sodium dichromate - Google Patents
Process for preparing sodium dichromate Download PDFInfo
- Publication number
- CN101693556A CN101693556A CN200910209582A CN200910209582A CN101693556A CN 101693556 A CN101693556 A CN 101693556A CN 200910209582 A CN200910209582 A CN 200910209582A CN 200910209582 A CN200910209582 A CN 200910209582A CN 101693556 A CN101693556 A CN 101693556A
- Authority
- CN
- China
- Prior art keywords
- carbonization
- sodium
- sodium dichromate
- preparation
- concentration
- 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.)
- Pending
Links
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The invention provides a process for preparing sodium dichromate, namely producing the sodium dichromate through a carbonization method comprising: converting sodium chromate into the sodium dichromate via carbon dioxide under pressurizing condition; delivering sodium chromate neutral liquor with impurities removed to a carbonization tower after a cascade reaction of more than three continuous towers; obtaining carbonizing liquor by controlling different gradient parameters (concentration and temperature of the carbonizing liquor, partial pressure of the carbon dioxide, carbonizing time and the like), continuously carbonizing and separating under pressure; obtaining sodium dichromate finished products through concentrating, filtering, evaporating, crystallizing and centrifugal dehydrating.
Description
Technical field
The present invention relates to the preparation method of sodium dichromate in the chromic salts industry.
Background technology
Sodium dichromate (sodium dichromate 99) is important basic chemical industry raw material, is mainly used in Chemicals such as producing chromic trioxide, chrome yellow, chromoxide green and potassium bichromate.Make auxiliary agent in printing and dyeing industry, electroplating industry and leather industry, also as oxygenant, Application Areas is very extensive in chemical industry and pharmaceutical industry.
At present, countries in the world mainly contain sulfuric acid process, electrolytic process and carborization by the method for Sodium chromate system sodium dichromate.Sulfuric acid process is the method that China and majority state adopt, but the shortcoming of sulfuric acid process is to consume sulfuric acid, and sodium sulfate byproduct contains 0.1% sexavalent chrome, and cost is higher relatively.Compare with sulfuric acid process, electrolytic process quality product height, but by product Returning utilization, but the electrolytic process power consumption is high, the cost height.Therefore, both at home and abroad always " carborization production sodium dichromate " as the technology main direction.
Summary of the invention
" carborization production sodium dichromate " production technology replaces sulfuric acid acidation with carbonic acid gas.When carbonic acid gas increased at pressure, gas concentration lwevel increased in the aqueous solution, and carbonic acid gas and water generate carbonic acid and ionization, made hydrogen ion increase, and the acidic conditions that provides makes chromate ion become dichromate ion, replaced sulfuric acid to play acidification.Its major advantage has:
1, saves sulfuric acid and soda ash.The sulfuric acid process byproduct is a sodium sulfate; Carborization replaces sulfuric acid with carbonic acid gas, and byproduct is a sodium bicarbonate, can replace the soda ash recycle, and chemical equation is as follows:
2, improve the quality.Finished product institute chloride is mainly from soda ash, and carborization makes chloride content decline in the finished product because of saving soda ash.Carborization is without sulfuric acid, and sulphate content must reduce in the finished product.
3, do not produce and contain the chromium saltcake.Because the sulfate radical-free ion adds in the Production Flow Chart, therefore do not produce and contain the chromium saltcake, alleviate environmental protection pressure.The sodium bicarbonate reusable edible of attached product.
4, improve equipment corrosion.Carborization is without sulfuric acid, and equipment corrosion reduces.
5, can reduce Carbon emission.
The present invention is by the above cascade reaction of continuous 3 towers, Sodium chromate neutral solution after the removal of impurities is sent into carbonating tower, different gradient parameter controls (dividing potential drop of the concentration of carbodiimide solution, temperature, carbonic acid gas and carbonization time etc.), continuous carbonization, band are pressed to separate and are obtained carbodiimide solution, again through evaporative crystallization, the centrifugal finished product that obtains.
Carbodiimide solution concentration at different levels (in Na2Cr2O7.2H2O) are at 500-1300g/L in the carbonization process.Attemperation is to 20-80 ℃ respectively with carbonating tower according to carbonization progression difference for temperature control, and the carbonization outlet temperature of high density carbonization tower is controlled at below 40 ℃, and the lower concentration carbonating tower can suitably improve temperature.Concentration of carbon dioxide is at 20-90%, every grade of gradient
Wherein c is the starting point concentration of carbonic acid gas, and n is total progression, and m is a progression, and j is gradient factor (j=0.5-1.5).Pressure is 0.01-1.5Mpa, and for guaranteeing carbonating towers energy at different levels continuous carbonization, partially carbonized tower can adopt normal pressure even negative pressure to handle.Carbonization time is 1-24 hour, and lower concentration carbodiimide solution carbonization time is shorter relatively, and high density carbonization liquid carbonization time is longer relatively, adds Sodium chromate carbonization crystal seed after carbonization carbonic acid gas to the solution reaches capacity in carbonating tower.
Embodiment
Embodiment 1: a kind of preparation method of sodium dichromate carries out according to the following steps:
1. feed intake, the neutral solution input carbonating tower of 500g/L;
2. temperature control is regulated differing temps respectively at 20-80 ℃ according to carbonization progression difference with carbonating tower, and the carbonization outlet temperature of high density carbonization tower is controlled at below 40 ℃.
3. ventilation is regulated the carbonating tower carbonization pressure to 1.5Mpa, and gas concentration lwevel is 80%.
4. control carbonization time, the control carbonization time is 10 hours, after carbonization carbonic acid gas to the solution reaches capacity in carbonating tower adding Sodium chromate carbonization crystal seed, the crystallization that is beneficial to sodium bicarbonate is separated out with Sodium chromate and is converted into sodium dichromate 99.
5. separate, adopt plate-and-frame filter press that carbodiimide solution is carried out press filtration and remove sodium bicarbonate crystal, remaining sodium bicarbonate crystal and the Sodium chromate for transforming are removed in reconcentration carbodiimide solution, filtration.
6. evaporative crystallization evaporates the carbodiimide solution behind the removal impurity, and carbonation rate is elevated to more than 95%.
7. centrifuge dehydration obtains the sodium dichromate product.
Embodiment 2: a kind of preparation method of sodium dichromate carries out according to the following steps:
1. feed intake, the neutral solution input carbonating tower of 600g/L;
2. temperature control is regulated differing temps respectively at 20-80 ℃ according to carbonization progression difference with carbonating tower, and the carbonization outlet temperature of high density carbonization tower is controlled at below 40 ℃.
3. ventilation is regulated the carbonating tower carbonization pressure to 1.5Mpa, and gas concentration lwevel is 90%.
4. control carbonization time, the control carbonization time is 8 hours, after carbonization carbonic acid gas to the solution reaches capacity in carbonating tower adding Sodium chromate carbonization crystal seed, the crystallization that is beneficial to sodium bicarbonate is separated out with Sodium chromate and is converted into sodium dichromate 99.
5. separate, adopt plate-and-frame filter press that carbodiimide solution is carried out press filtration and remove sodium bicarbonate crystal, remaining sodium bicarbonate crystal and the Sodium chromate for transforming are removed in reconcentration carbodiimide solution, filtration.
6. evaporative crystallization evaporates the carbodiimide solution behind the removal impurity, and carbonation rate is elevated to more than 95%.
7. centrifuge dehydration obtains the sodium dichromate product.
Claims (6)
1. the preparation method of a sodium dichromate, it is characterized in that: by continuous multitower cascade reaction, Sodium chromate neutral solution after the pre-carbonization removal of impurities is sent into the carbonating tower carbonization, by different gradient parameter controls (dividing potential drop of the concentration of carbodiimide solution, temperature, carbonic acid gas and carbonization time etc.), continuous carbonization, band are pressed to separate and are obtained carbodiimide solution, concentrate, filter, obtain the sodium dichromate finished product through evaporative crystallization, centrifuge dehydration again.
2. the preparation method of a kind of sodium dichromate according to claim 1 is characterized in that the above cascade reaction of continuous multitower, and carbonization progression is 3
-10 grades.
3. the preparation method of a kind of sodium dichromate according to claim 1, it is characterized in that different gradient parameter control (pressure of the concentration of carbodiimide solution, temperature, carbonic acid gas and carbonization time etc.) continuous carbonizations, carbodiimide solution concentration at different levels (Na2Cr2O7.2H2O meter) are 500
-1300g/L, the concentration of every grade carbon-dioxide is 20
-90%; Pressure 0.01
-1.5Mpa temperature is 20
-80 ℃, carbonization time is 1
-24 hours.
4. the preparation method of a kind of sodium dichromate according to claim 1 is characterized in that Sodium chromate carbonization crystal seed manufacturing way is: with the sodium bicarbonate screening, collection cut size is 0.001
-0.05mm between material, join in the solution saturated with sodium chromate as crystal seed.
5. the preparation method of a kind of sodium dichromate according to claim 1 is characterized in that band pressure separation employing sheet frame, diaphragm filter press, chamber-type press filter etc.
6. the preparation method of a kind of sodium dichromate according to claim 1, it is characterized in that carbonating tower adopts anti-bonding joint technology, spraying or bonding viton in the carbonating tower, poly-fluorine material (F40 tetrafluoroethylene and ethylene copolymer, F46 gathers perfluoro second propylene, F30 trifluorochloroethylene and ethylene copolymer, F23 vinylidene and chlorotrifluoroethylene, F24 vinylidene and TFE copolymer, F26 vinylidene and hexafluoropropylene copolymer, the multipolymer of ETFE tetrafluoroethylene and ethene, ECTFE ethene one chlorotrifluoroethylene, materials such as PTFE tetrafluoroethylene) etc.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910209582A CN101693556A (en) | 2009-10-30 | 2009-10-30 | Process for preparing sodium dichromate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910209582A CN101693556A (en) | 2009-10-30 | 2009-10-30 | Process for preparing sodium dichromate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101693556A true CN101693556A (en) | 2010-04-14 |
Family
ID=42092572
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200910209582A Pending CN101693556A (en) | 2009-10-30 | 2009-10-30 | Process for preparing sodium dichromate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101693556A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102408131A (en) * | 2011-09-09 | 2012-04-11 | 甘肃锦世化工有限责任公司 | Method for improving industrial sodium dichromate finished product content |
| CN102642870A (en) * | 2011-06-09 | 2012-08-22 | 四川省安县银河建化（集团）有限公司 | Method for continuously neutralizing and decontaminating sodium chromate alkali solution |
| CN102649584A (en) * | 2011-08-22 | 2012-08-29 | 四川省安县银河建化（集团）有限公司 | Preparation method of sodium bichromate |
| CN102649585A (en) * | 2011-08-22 | 2012-08-29 | 四川省安县银河建化（集团）有限公司 | Preparation method of sodium bichromate |
| CN102674458A (en) * | 2012-05-18 | 2012-09-19 | 中国科学院过程工程研究所 | Method for preparing sodium bichromate by continuous carbonization with single kettle |
| CN102897838A (en) * | 2012-11-19 | 2013-01-30 | 四川省安县银河建化（集团）有限公司 | One-step preparation method of sodium bichromate |
| CN102935327A (en) * | 2012-11-23 | 2013-02-20 | 四川省安县银河建化（集团）有限公司 | Method for removing sulfur dioxide in tail gas from industrial kiln and method for comprehensively utilizing tail gas from industrial kiln |
| CN103086433A (en) * | 2013-03-11 | 2013-05-08 | 湖北振华化学股份有限公司 | Method for preparing sodium dichromate by sodium-based molten salt oxidation continuous carbonization |
-
2009
- 2009-10-30 CN CN200910209582A patent/CN101693556A/en active Pending
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102642870B (en) * | 2011-06-09 | 2015-11-25 | 四川省银河化学股份有限公司 | With the method for removal of impurities during a kind of chromium acid sodium alkaline liquid is continuous |
| CN102642870A (en) * | 2011-06-09 | 2012-08-22 | 四川省安县银河建化（集团）有限公司 | Method for continuously neutralizing and decontaminating sodium chromate alkali solution |
| CN102649585B (en) * | 2011-08-22 | 2014-05-14 | 四川省银河化学股份有限公司 | Preparation method of sodium bichromate |
| CN102649585A (en) * | 2011-08-22 | 2012-08-29 | 四川省安县银河建化（集团）有限公司 | Preparation method of sodium bichromate |
| CN102649584B (en) * | 2011-08-22 | 2014-08-13 | 四川省银河化学股份有限公司 | Preparation method of sodium bichromate |
| CN102649584A (en) * | 2011-08-22 | 2012-08-29 | 四川省安县银河建化（集团）有限公司 | Preparation method of sodium bichromate |
| CN102408131B (en) * | 2011-09-09 | 2013-09-04 | 甘肃锦世化工有限责任公司 | Method for improving industrial sodium dichromate finished product content |
| CN102408131A (en) * | 2011-09-09 | 2012-04-11 | 甘肃锦世化工有限责任公司 | Method for improving industrial sodium dichromate finished product content |
| CN102674458A (en) * | 2012-05-18 | 2012-09-19 | 中国科学院过程工程研究所 | Method for preparing sodium bichromate by continuous carbonization with single kettle |
| CN102897838A (en) * | 2012-11-19 | 2013-01-30 | 四川省安县银河建化（集团）有限公司 | One-step preparation method of sodium bichromate |
| CN102897838B (en) * | 2012-11-19 | 2014-12-10 | 四川省银河化学股份有限公司 | One-step preparation method of sodium bichromate |
| CN102935327A (en) * | 2012-11-23 | 2013-02-20 | 四川省安县银河建化（集团）有限公司 | Method for removing sulfur dioxide in tail gas from industrial kiln and method for comprehensively utilizing tail gas from industrial kiln |
| CN102935327B (en) * | 2012-11-23 | 2015-07-01 | 四川省银河化学股份有限公司 | Method for removing sulfur dioxide in tail gas from industrial kiln and method for comprehensively utilizing tail gas from industrial kiln |
| CN103086433A (en) * | 2013-03-11 | 2013-05-08 | 湖北振华化学股份有限公司 | Method for preparing sodium dichromate by sodium-based molten salt oxidation continuous carbonization |
| CN103086433B (en) * | 2013-03-11 | 2015-01-14 | 湖北振华化学股份有限公司 | Method for preparing sodium dichromate by sodium-based molten salt oxidation continuous carbonization |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101693556A (en) | Process for preparing sodium dichromate | |
| CN109650414B (en) | Method and system for preparing battery-grade and high-purity-grade lithium hydroxide and lithium carbonate by using high-impurity lithium source | |
| CN102320641B (en) | Resource utilization method for saponification waste water producing epoxypropane by chlorohydrination process | |
| CN111484178B (en) | Comprehensive treatment method for seawater or strong brine | |
| CN109052434B (en) | Method for jointly producing soda ash and composite nitrogen fertilizer by taking mirabilite and ammonium bicarbonate as raw materials | |
| CN111634928B (en) | Method for preparing large-particle baking soda by secondary carbonization method and obtained baking soda | |
| CN101234767A (en) | Thick seawater comprehensive utilization technique after seawater desalination | |
| CN107366005B (en) | A kind of process of sodium sulphate type bittern perhalogeno ionic membrane caustic soda by-product anhydrous sodium sulphate | |
| CN109680295B (en) | A kind of method that industry level lithium carbonate solid prepares lithium hydroxide | |
| CN107935264A (en) | A kind of sea water desalination salt manufacturing comprehensive technological method | |
| CN102344154A (en) | Method for preparing high-purity magnesium chloride hexahydrate from waste brine | |
| CN101891256B (en) | Production technique of high-purity potassium permanganate and manganese dioxide, and carbon dioxide reaction tower | |
| CN103193271B (en) | Method for producing high-quality sodium bichromate | |
| CN111099698A (en) | Forward osmosis and combined soda production process co-production combined system and method | |
| CN110937612B (en) | Process for preparing high-quality heavy soda ash by using crude sodium bicarbonate | |
| CN109020021A (en) | It is a kind of sea desalination and strong brine comprehensively utilize energy saving technique | |
| CN103626210A (en) | Method for preparing magnesium hydroxide and chlorine by coupling magnesium chloride reactive crystallization and electrolysis | |
| CN107986299A (en) | The method that saltcake liquid phase round-robin method prepares soda ash and caustic soda | |
| CN111003717A (en) | Device and method for preparing alkali salt by evaporating and crystallizing sea water desalination strong brine | |
| CN106829866A (en) | The technique that a kind of use bittern produces hydrochloric acid | |
| CN101559986A (en) | Method for producing iron oxide black | |
| CN211497025U (en) | Forward osmosis and combined soda production process co-production combined system | |
| CN102649585B (en) | Preparation method of sodium bichromate | |
| CN112678973A (en) | Method for dechlorinating ammonia flue gas desulfurization circulating liquid | |
| CN102649584B (en) | Preparation method of sodium bichromate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Open date: 20100414 |