METHOD OF COMPLEX REPROCESSING OF MAGNESIUM-SILICATE RAW MATERIALS Russian patent published in 2006 - IPC C01F5/06 C01B33/142 

FIELD: chemical industry; construction industry; high-heat industry; electrotechnical industry; metallurgical industry; rubber-technical industry; glass industry; other industries; methods of the complex reprocessing of magnesium-silicate-containing raw materials.

SUBSTANCE: the invention is pertaining to the technique of reprocessing of the mineral natural raw materials and may be used in chemical, construction, high-heat, electrotechnical, metallurgical, rubber-technical, glass and other industries. The original raw materials are subjected to the two-stage leaching. At that on the second stage of the leaching the sulfuric acid is fed, then the solid phase after the second stage of the leaching is separated by the decantation, centrifuging. After that it is flushed, dried, comminuted and classified with separation from the amorphous finely dispersed silicon dioxide of the macrocrystalline admixture (olivine, serpentine, magnoferrite, chrompicotite and quartz). The acid solution separated by centrifuging is fed onto the first stage of the leaching of the original raw material. Then conduct the filtration and the partially leached raw material is sent onto the second stage of the leaching, and the filtrate is subjected to treatment with the hydrogen peroxide and then with the water solution of ammonia up to pH 4.5-5.5. The formed hydroxides are filtered out, and the clarified filtrate is treated with the ammonium persulfate and subjected to the neutralization with the water solution of ammonia up to pH 6.8-7.2. The received suspension is subjected to the fine filtration with separation of the fine-dispersed sediment of manganese dioxide. The purified filtrate is cooled to the temperature of 18-55°C and thinned in 10-20 time, introduce the seeds of the carbonate of a

magnesium carbonate of a in amount of 0.1-10.0 mass % and conduct its carbonization by the gaseous carbon dioxide at the constant keeping pH within the limits of 9.5-11.0 using the gaseous ammonia. The settled carbonate is flushed simultaneously with the filtration in the beginning - by the solution with pH 9.5-10.0, then - by the demineralized water. The filtered out magnesium carbonate is dried at the temperature of 105-200°C, and then it is calcined at the temperature of 480-650°C. The filtrate after separation of the magnesium carbonate is subjected to decarbonization with extraction of the carbon dioxide, which is sent back to the stage of the carbonization, and the filtrate representing the solution of the ammonium sulfate, is treated with the suspension of the calcium hydroxide, heated with extraction of the gaseous ammonia and the calcium sulfate sediment is filtered out. The received filtrate is treated with the aluminum hydroxide and the oxalic acid for additional removal of the calcium ions and sulfate-ions, then they filtrate and remove the sediment of the calcium oxalate and the dual salt of the sulfate of calcium and aluminum. The ammonia solution cleared at this stage is partially routed to the reactivation of ammonia and partially used for flushing of the magnesium carbonate. The extracted on the stage of the reactivation the gaseous ammonia with the admixture of the carbon dioxide and the carbon dioxide with fragments of the magnesium carbonate from the stage of calcinations of the magnesium carbonate are fed back to the stage of carbonization; and the steam from the stage of the magnesium carbonate drying is condensed and sent to the first stage of the leaching. The invention allows to complexly reprocess the natural magnesium-silicate-containing raw materials within the closed cycle.

EFFECT: the invention ensures the complex reprocessing of the natural magnesium-silicate-containing raw materials within the closed cycle.

1 dwg, 5 tbl