Continuous process for producing an aqueous solution of ferric chloride

Abstract

An aqueous solution of ferric chloride directly usable for purifying water is produced from a pickling liquor containing ferrous chloride by a process comprising the steps of 1. continuously concentrating the pickling liquor by evaporation to at least about 34.25% by weight ferrous chloride concentration; 2. continuously neutralizing the resulting concentrated liquor, which still contains free hydrochloric acid, by means of a fluidized bed of iron oxide particles (e.g. mill scales); and 3. continuously countercurrently chlorinating the resulting neutralized concentrated liquor in two successive reaction zones, to the extent of from 73 to 86% at a temperature of from 35.degree. to 75.degree. C in the first reaction zone and the balance at a temperature of from 40.degree. to 100.degree. C in the second reaction zone. The product of said process is an aqueous solution containing per liter at least 40% by weight of ferric chloride, less than 0.1% by weight of ferrous chloride and less than 0.1% by weight of ferrous chloride. Chlorination yield is practically quantitative.

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