A process of production of potassium ammonium sulfate compound fertilizer in cost-effective manner directly from concentrated sea bittern
AssigneeCouncil of Scientific and Industrial Research
InventorsPratyush Maiti, Krishna Kanta Ghara, Pushpito Kumar Ghosh
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Abstract
The present invention provides process for production of potassium ammonium sulfate compound fertilizer through the reaction of Epsom salt, obtained in course of chilling of concentrated sea bittern (32-33° Be), with potassium bitartrate, precipitated from such bittern, and ammonium hydroxide. While process integration was achieved through utilisation of Epsom salt; partial desulphatation of bittern, through crystallization of Epsom salt, resulted in about 17% improvement in K+ precipitation efficiency.
Claims4
An integrated process for production of potassium ammonium sulphate compound fertilizer, by recovering potassium from sea bittern, through the reaction of Epsom salt, obtained in course of chilling of concentrated sea bittern (32-33° Be), with potassium bitartrate, precipitated from such bittern, and ammonium hydroxide and the said process comprising the steps of:
- i. concentrating sea bittern to 32 to 33° Be;
- ii. adding 5 to 10% water into the concentrated sea bittern followed by chilling at a temperature range of 0° C.-7° C. for recovery of Epsom salt and partially desulphated bittern;
- iii. reacting the partially de-sulphated bittern with magnesium tartrate and sulphuric acid to obtain potassium bitartrate and K-depleted bittern;
- iv. reacting potassium bi-tartrate with Epsom salt as obtained in step (ii) and ammonia solution to produce K(NH4)SO4 solution and to precipitate magnesium tartrate;
- v. treating the K(NH4)SO4 solution obtained in step (iv) with calcium carbonate or calcium oxide and sulphuric acid, to obtain solid calcium tartrate and K(NH4)SO4 solution;
- vi. treating the K(NH4)SO4 solution obtained in step (v) with ammonia and carbon dioxide, to precipitate residual Mg2+ as magnesium carbonate and generate nearly pure K(NH4)SO4 solution;
- vii. mixing the K-depleted bittern obtained in step (iii) with water/seawater and reacting the dilute bittern with calcium carbonate or calcium oxide and sulphuric acid to precipitate out residual tartaric acid in the form of insoluble calcium tartrate;
- viii. reacting calcium tartrate, obtained in steps (v) and (vii), with sodium carbonate to produce solution of disodium tartrate along with precipitation of calcium carbonate;
- ix. adding the magnesium tartrate, obtained in step (iv) and disodium tartrate, obtained in step (viii) into a fresh lot of partially de-sulphated bittern along with sulphuric acid to once again precipitate out potassium bi-tartrate;
- x. using the calcium carbonate, obtained in step (viii), in steps (v) and (vii);
- xi. evaporating the K(NH4)SO4 solution obtained in step (vi) to produce solid potassium ammonium sulphate compound fertilizer.
Dependencies are inferred from the claim text.