Treatment of basalt, lava and other silicate(s) - by roasting, milling and leaching, to obtain filter material with large specific surface, and also valuable lanthanide concentrate

摘要

Mfr. of a filter material with a large specific surface (SS) is described. A mixt. is made contg. by wt. 55-80% finely milled basalt, lava, and possibly another silicate (I), all pref. with size below 70 mu m; plus 5-15% sodium- or potassium-silicate; and 5-10% carbonaceous material (II). The mixt. is sintered at 973.15-1173-15 degrees K., and then milled to size. Cpd. (I) is pref. attacked by boraz or borate fluxes; whereas (II) is pref. soot, coke, anthracite, cellulose, wood chips or sawdust. The sintered and milled prod. is pref. leached with 25% HCl and/or 25% HNO2 and washed, the resulting liq. being used to recover lanthanides present in the initial basalt lava and cpd. (I). Typically the final prod. has a particle size below 0.4 mm and SS over 300 m2/g and valuable lanthanides are obtd. during the process.