Efficient Recovery of Potassium Chloride from Liquid Effluent Generated during Preparation of Schoenite from Kainite Mixed Salt and Its Reuse in Production of Potassium Sulfate
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- 作者：Rohit H. Dave and Pushpito K. Ghosh
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2006
- 出版时间：March 1, 2006
- 年：2006
- 卷：45
- 期：5
- 页码：1551 - 1556
- 全文大小：86K
- 年卷期：v.45,no.5(March 1, 2006)
- ISSN：1520-5045
文摘
Although bittern of oceanic origin can be utilized for the production of K2SO4 via kainite (KCl·MgSO4·2.75H2O) and schoenite (K2SO4·MgSO4·6H2O) double salts, certain limitations are encountered in practice.These include (i) difficulties in obtaining pure schoenite from crude kainite and (ii) the requirement of KClin the K2SO4 forming process. When schoenite is prepared from kainite through a simple reaction-cum-leaching process and the liquid effluent is desulfated with CaCl2 as part of a scheme to coproduce magnesia(Ghosh et al. U.S. Patent Publication No. 2005/0220698 A1, 2005 (Notice of Allowance); International PatentPublication No. WO 2005/063626 A1, July 14, 2005), the composition of the resultant effluent is found tobe ideally positioned in the phase diagram for direct recovery of sylvinite (NaCl/KCl). The intermediatesteps of carnallite crystallization and decomposition, encountered during sylvinite preparation from Dead Seabrine and desulfated oceanic bittern, are avoided as a result. In this manner, 70-80% of the KCl in theeffluent can be recovered, which largely fulfils the requirement for K2SO4 preparation. The amount of waterthat must be evaporated is 6.5-7.5 kg per kg of KCl in the form of sylvinite.