Recovery of potassium as hydroxide from carnallite ores - using recycling steps for effluent to obtain better yield

摘要

In a method of treating ores contg. carnallite (KCl.MgCl2.6H2O), the ore is first ground so that the amt. of NaCl 0.5mm in the ground ore is at least equal to the amt. of chloride to be separated from the artificial sylvinite to be obtd. subsequently, then partly decomposed by contact with a recycled soln. which contains but is not satd. with MgCl2. The fine fraction of the pulp obtd. is separated and the decompsn. of the remaining coarse fraction is terminated by contact with a recycled soln. which is low in MgCl2, to obtain an artificial sylvinite. The fraction of sylvinite 0.5 mm, is removed and the enriched artificial sylvinite thus obtd. is treated to recover potassium concentrate. Recycling the soln. permits recovery of some potassium from chloride which otherwise would go to waste as in prior art. It also economises on use of water. The method overcomes the prior art problem of insufficiency of KCl in the artificial sylvinite, so that it is possible to obtain a commercially acceptable product. (i.e. contg. 60% K2O) by simple washing.