Processes for preparing alumina and magnesium chloride by HCl leaching of various materials

摘要

The disclosed processes can be effective for treating various materials comprising several different metals. These materials can be leached with HCl for obtaining a leachate and a solid. Then, they can be separated from one another and a first metal can be isolated from the leachate. Then, a second metal can further be isolated from the leachate. The first and second metals can each be substantially selectively isolated from the leachate. This can be done by controlling the temperature of the leachate, adjusting pH, further reacting the leachate with HCl, etc. The metals that can be recovered in the form of metal chlorides can eventually be converted into the corresponding metal oxides, thereby allowing for recovering HCl. The various metals can be chosen from aluminum, iron, zinc, copper, gold, silver, molybdenum, cobalt, magnesium, lithium, manganese, nickel, palladium, platinum, thorium, phosphorus, uranium, titanium, rare earth element and rare metals.

主权项

1. A process for preparing alumina, said process comprising:
leaching an aluminum-containing material with HCl so as to obtain a leachate comprising aluminum ions, magnesium ions and a solid, and separating said solid from said leachate; substantially selectively precipitating MgCl2 from said leachate under conditions effective for controlling solubility of MgCl2 based on at least one parameter chosen from temperature, acid concentration and chlorides concentration and removing said MgCl2 from said leachate; reacting said leachate with HCl so as to obtain a liquid and a precipitate comprising said aluminum ions in the form of AlCl3, and separating said precipitate from said liquid; optionally reacting said precipitate with a base; treating said precipitate under conditions effective for converting said precipitate into Al2O3 and optionally recovering gaseous HCl so-produced; and treating said MgCl2 under conditions effective for converting it into MgO and optionally recovering gaseous HCl so-produced,wherein MgCl2 is substantially selectively precipitated from said leachate and removed therefrom and then, said leachate is reacted with HCl so as to obtain said liquid and said precipitate comprising said aluminum ions in the form of AlCl3, and separating said precipitate from said liquid.