one. Background and meaning
Potassium sulphate is a scarce product in China. It is used as a high-quality potash fertilizer in agriculture. It is especially suitable for tobacco, sugar cane, grape, citrus, tea, watermelon, potato and other economic crops that avoid chlorine. It is also one of the raw materials for manufacturing ternary chlorine-free compound fertilizer; It is used industrially to produce various potassium salts and feed additives. We have been engaged in the research of bitter brine to prepare potassium sulfate, and cooperated with Daqinghe Salt Field in Hebei Province to establish a production facility of 100 million tons/year, which was put into production and succeeded. It not only adapts to the shortage of domestic potassium sulfate market, but also reduces the import amount of potassium sulfate for the country, thus saving certain foreign exchange and state financial subsidies for agricultural potassium sulfate, and fully utilizing the full utilization of magnesium sulfate resources in sea salt bitter brine. Thereby increasing the economic benefits of salt companies. Both social and economic benefits are obvious.
The project was completed by the National Oceanic Administration's Institute of Seawater Desalination and Comprehensive Utilization, and won the third prize of National Science and Technology Invention and the Second Prize of Science and Technology Progress of the Ministry of Light Industry.
two. Main technical content
The direct extraction of potassium sulphate from bitter brine is the invention of our patent. It is the first technology in China, which fills the gap in the process of direct preparation of potassium sulphate from domestic bituminous brine, and provides a reliable way for self-sufficiency of potassium sulphate in China. The direct preparation of potassium sulphate from bitter brine is based on the production of potassium chloride from the traditional bitter brine, by changing the structure of the raw materials produced, thereby changing the composition of the mixed salt of heating and evaporation, and adding a conversion to the mixed salt. Flotation separation, washing, and two-stage conversion with potassium chloride to produce a new product of potassium sulfate.
1. Scale and capacity: 10 000 tons of potassium sulphate / annual production unit, by-product industrial salt 10,000 tons.
2. Product quality: Meet the superior product standard of ZBG21006-89 potassium sulfate for agriculture. K2O content ≥ 50.0%; chlorine (Cl) content ≤ 1.5%; moisture content ≤ 1.0%.
3. Process flow: mixing the carnallite produced by the system with the salt mother liquor, the mother liquor and the salt tail slurry of the system and the bitter brine, and separating the mixed halogen and salt slurry by sedimentation (the salt slurry is dehalogenated industrial salt product) ). The mixed halogen is subjected to double-effect evaporation to produce an evaporation completion liquid, and then the thermal separation is carried out to separate the clear liquid and the mixed salt. The clarified liquid is settled by cooling in a vacuum crystallizer, and the carnallite and the old halogen (the old halogen is supplied to bromine and magnesium chloride) are separated. After the mixed salt is vacuum-dehalogenated, the mashing liquid is added to the stirring tank for a certain conversion, and then the collector and the foaming agent are added to the flotation machine for flotation separation to obtain the strontium and the salt tail slurry and the mother liquor, and the potassium is used. After the mother liquor is washed, it is separated by sedimentation centrifugation to obtain fine sputum and sputum washing liquid, and the mashing liquid is used for a conversion with the mixed salt. The fine water is heated and dissolved, and then potassium chloride is added for two-stage conversion, and then the wet potassium sulfate and potassium mother liquor are separated by sedimentation centrifugal dehydration, the potassium mother liquor is used for the hydrazine washing, and the wet potassium sulfate is dried and packaged to be the potassium sulfate product.
three. Application situation and development and utilization prospects
The technology was built in 1994 at the Daqinghe Salt Field Chemical Plant in Hebei Province, and a production plant of 10,000 tons/year was built. The test was started in April and it was successful. He was awarded the second prize of scientific and technological progress of the Ministry of Light Industry and the third prize of national invention.
The technology uses the original plant equipment transformation, and the new potassium sulfate conversion process, an investment of 5.81 million yuan, after deducting by-products, the workshop cost is 1,284 yuan / ton, the annual profit is 2.68 million yuan, and the tax is 480,000 yuan (based on 1,600 yuan / ton K2SO4) ).
Potassium sulphate is a scarce product in China. It is used as a high-quality potash fertilizer in agriculture. It is especially suitable for tobacco, sugar cane, grape, citrus, tea, watermelon, potato and other economic crops that avoid chlorine. It is also one of the raw materials for manufacturing ternary chlorine-free compound fertilizer; It is used industrially to produce various potassium salts and feed additives. We have been engaged in the research of bitter brine to prepare potassium sulfate, and cooperated with Daqinghe Salt Field in Hebei Province to establish a production facility of 100 million tons/year, which was put into production and succeeded. It not only adapts to the shortage of domestic potassium sulfate market, but also reduces the import amount of potassium sulfate for the country, thus saving certain foreign exchange and state financial subsidies for agricultural potassium sulfate, and fully utilizing the full utilization of magnesium sulfate resources in sea salt bitter brine. Thereby increasing the economic benefits of salt companies. Both social and economic benefits are obvious.
The project was completed by the National Oceanic Administration's Institute of Seawater Desalination and Comprehensive Utilization, and won the third prize of National Science and Technology Invention and the Second Prize of Science and Technology Progress of the Ministry of Light Industry.
two. Main technical content
The direct extraction of potassium sulphate from bitter brine is the invention of our patent. It is the first technology in China, which fills the gap in the process of direct preparation of potassium sulphate from domestic bituminous brine, and provides a reliable way for self-sufficiency of potassium sulphate in China. The direct preparation of potassium sulphate from bitter brine is based on the production of potassium chloride from the traditional bitter brine, by changing the structure of the raw materials produced, thereby changing the composition of the mixed salt of heating and evaporation, and adding a conversion to the mixed salt. Flotation separation, washing, and two-stage conversion with potassium chloride to produce a new product of potassium sulfate.
1. Scale and capacity: 10 000 tons of potassium sulphate / annual production unit, by-product industrial salt 10,000 tons.
2. Product quality: Meet the superior product standard of ZBG21006-89 potassium sulfate for agriculture. K2O content ≥ 50.0%; chlorine (Cl) content ≤ 1.5%; moisture content ≤ 1.0%.
3. Process flow: mixing the carnallite produced by the system with the salt mother liquor, the mother liquor and the salt tail slurry of the system and the bitter brine, and separating the mixed halogen and salt slurry by sedimentation (the salt slurry is dehalogenated industrial salt product) ). The mixed halogen is subjected to double-effect evaporation to produce an evaporation completion liquid, and then the thermal separation is carried out to separate the clear liquid and the mixed salt. The clarified liquid is settled by cooling in a vacuum crystallizer, and the carnallite and the old halogen (the old halogen is supplied to bromine and magnesium chloride) are separated. After the mixed salt is vacuum-dehalogenated, the mashing liquid is added to the stirring tank for a certain conversion, and then the collector and the foaming agent are added to the flotation machine for flotation separation to obtain the strontium and the salt tail slurry and the mother liquor, and the potassium is used. After the mother liquor is washed, it is separated by sedimentation centrifugation to obtain fine sputum and sputum washing liquid, and the mashing liquid is used for a conversion with the mixed salt. The fine water is heated and dissolved, and then potassium chloride is added for two-stage conversion, and then the wet potassium sulfate and potassium mother liquor are separated by sedimentation centrifugal dehydration, the potassium mother liquor is used for the hydrazine washing, and the wet potassium sulfate is dried and packaged to be the potassium sulfate product.
three. Application situation and development and utilization prospects
The technology was built in 1994 at the Daqinghe Salt Field Chemical Plant in Hebei Province, and a production plant of 10,000 tons/year was built. The test was started in April and it was successful. He was awarded the second prize of scientific and technological progress of the Ministry of Light Industry and the third prize of national invention.
The technology uses the original plant equipment transformation, and the new potassium sulfate conversion process, an investment of 5.81 million yuan, after deducting by-products, the workshop cost is 1,284 yuan / ton, the annual profit is 2.68 million yuan, and the tax is 480,000 yuan (based on 1,600 yuan / ton K2SO4) ).
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