Processes for treating magnesium-containing materials

Abstract

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.

What is claimed is: 
     
         1 . A process for treating a magnesium-containing material, said process comprising:
 leaching the magnesium-containing material with HCl so as to obtain a leachate comprising magnesium ions and ions from at least one metal and a solid, and separating said solid from said leachate; and   precipitating said at least one metal by reacting said leachate with a precipitating agent so as to obtain a liquid comprising said magnesium ions and a precipitate comprising said precipitated at least one metal, and separating said precipitate from said liquid.   
     
     
         2 . The process of  claim 1 , wherein said process comprises substantially selectively precipitating said magnesium ions by reacting said liquid with said precipitating agent. 
     
     
         3 . The process of  claim 1 , wherein said precipitating agent is a base. 
     
     
         4 . The process of  claim 2 , wherein said precipitating agent is Mg(OH) 2 . 
     
     
         5 . The process of  claim 1 , wherein said magnesium-containing material is serpentine. 
     
     
         6 . The process of  claim 1 , wherein said magnesium-containing material is asbestos. 
     
     
         7 . The process of  claim 1 , wherein said at least one metal is nickel. 
     
     
         8 . The process of  claim 1 , wherein said at least one metal is cobalt. 
     
     
         9 . The process of  claim 1 , wherein said at least one metal is iron. 
     
     
         10 . The process of  claim 1 , wherein said at least one metal is aluminum. 
     
     
         11 . The process of  claim 1 , wherein said process comprises:
 precipitating said a first metal by reacting said leachate with a precipitating agent so as to obtain said liquid comprising said magnesium ions and said precipitate comprising said precipitated first one metal, and separating said precipitate from said liquid; and   precipitating a second metal by reacting said liquid with a precipitating agent so as to obtain another liquid comprising said magnesium ions and another precipitate comprising said precipitated second metal, and separating said another precipitate from said another liquid.   
     
     
         12 . The process of  claim 11 , wherein said first metal is iron and said second metal is nickel. 
     
     
         13 . The process of  claim 12 , wherein said precipitating agent is a base. 
     
     
         14 . The process of  claim 11 , wherein said process further comprises reacting said another liquid with HCl so as to precipitate said magnesium ions in the form of MgCl 2 . 
     
     
         15 . A process for treating a magnesium-containing material, said process comprising:
 leaching the magnesium-containing material with HCl so as to obtain a leachate comprising magnesium ions and ions from at least one metal and a solid, and separating said solid from said leachate;   controlling the concentration of HCl in the leachate and/or the temperature of the leachate so as to precipitate the first metal in the form of a chloride, and removing the precipitate from the leachate; and   controlling the concentration of HCl in the leachate and/or the temperature of the leachate so as to precipitate a second metal in the form of a chloride, and removing the precipitate from the leachate.   
     
     
         16 . The process of  claim 15 , wherein said process comprises:
 controlling the concentration of HCl in the leachate so as to precipitate the first metal in the form of a chloride, and removing the precipitate from the leachate; and   controlling the concentration of HCl in the leachate so as to precipitate a second metal in the form of a chloride, and removing the precipitate from the leachate.   
     
     
         17 . The process of  claim 16 , wherein said process further comprises controlling the concentration of HCl in the leachate so as to precipitate said magnesium ions in the form of MgCl 2 . 
     
     
         18 . The process of  claim 17 , wherein said process further comprises reacting said magnesium ions with HCl so as to precipitate said magnesium ions in the form of MgCl 2 . 
     
     
         19 . The process of  claim 16 , wherein said first metal is iron and said second metal is nickel. 
     
     
         20 . The process of  claim 17 , wherein said first metal is iron and said second metal is nickel. 
     
     
         21 . The process of  claim 17 , wherein said process further comprises heating said MgCl 2 . 
     
     
         22 . The process of  claim 20 , wherein said process further comprises heating said MgCl 2  in the presence of HCl. 
     
     
         23 . The process of  claim 20 , wherein said process further comprises heating said MgCl 2  so as to convert said MgCl 2  into MgO.