METHOD OF PRODUCING THE REDUCING AGENT FOR SILICON AND PURE FERROSILICON SORTS MELTING Russian patent published in 1997 - IPC

FIELD: metallurgy, alloys. SUBSTANCE: after high-temperature coal roasting, cooling roasting products, their sifting from small particles and separation in water the roasting products were treated firstly with 10% alkali aqueous solution and then washed and decalcified in acid aqueous solution. In the process of leaching and decalcification temperature is maintained at the range 90-100 C and ratio solid : liquid - at the range 1:(5-8). Duration of leaching and declarification depends on size of roasting products - 1-4 and 2-6 h, respectively. Leaching is carried out with sodium hydroxide solution and declarification - with nitric acid. Before roasting and declarification roasting products were heated to 105-120 C. EFFECT: improved method of producing. 3 cl, 1 tbl