METHOD FOR EXTRACTION AND PROCESSING OF POTASSIUM-MAGNESIUM ORES FOR METALLIC MAGNESIUM Russian patent published in 1998 - IPC

FIELD: mining industry. SUBSTANCE: according to method, undertaken is underground lixiviation of ores by water solutions, then sludge is separated, performed is chemical settling of magnesium ions. Then sediment of magnesium hydroxide obtained from solution is separated and processed. Processing of sediment is carried out by treating it with exhaust gases which contain chlorous hydrogen and insoluble impurities created in process of producing metallic magnesium with subsequent separation of insoluble impurities from chlorous-hydrogen solution. Produced chlorine-magnesium solution is subjected to conversion with potassium chloride at high temperature. Performed is crystallization of carnallite with subsequent processing of carnallite into metallic magnesium by means of electrolizing of dehydrated melt of carnallite. Usable in function of water solutions for underground lixiviation process is neutralized effluent occurred from production of metallic magnesium with later returning of effluent to production cycle consisting of lixiviation of ores that is chemical settling of magnesium hydroxide and separation of magnesium hydroxide sediment from solution. Chemical settling of magnesium ions from solutions of underground lixiviation can be carried out by simultaneous and continuous delivery into reactor of underground lixiviation solution and disintegrated unslaked lime or suspension of slaked lime in neutralized effluent from magnesium production at maintaining surplus of magnesium ions in reactor. In addition, treatment of obtained magnesium hydroxide sediment by exhaust gases from magnesium production can be carried out at first stage of gas cleaning by spraying suspension of magnesium hydroxide in cleaning scrubber by counterflow as to exhaust gases with content of main substance within 120-210 kg/t of suspension. Suspension of magnesium chloride with magnesium hydroxide created at first stage of gas cleaning is circulated in system of scrubber - settling tank. After that, solution is subjected to conversion into synthetic carnallite. Application of aforesaid method allows for reducing expenses for winning and processing of ores for production of magnesium. In addition, underground operations are excluded. Reduced is amount of solid salt waste resulted from production of magnesium. EFFECT: higher overall efficiency. 7 cl