Recovery of asbestos mine tailings - for use as refractories, glass, abrasives etc. by addition of various components including metal oxide(s)

摘要

Tailings from asbestos mines alone or with natural or artificial additives are used as moulded fibrous or sintered refractories, abrasives or glass ceramics. The material which consists mainly of antigorite and chrysotile, low in Al2O3 and Ni, when fired consists of enstatite m.pt 1500 degrees C) and forsterite (m.pt 1800-1890 degrees C). This is cleaned of residual fibres, and sepd. from iron cpds. by grinding and magnetic sepn. (wet or dry) then pref. mixed with 5-20% MgO and fused in an electric furnace to react the MgO with the low melting enstatite to form a refractory for sterite. In other embodiments, the material is mixed with 40-70% Al2O3 or MgO to form refractories; 5-25% Fe2O3 to form glass ceramics; or with a mixt. of =1 of 5-25% CaO, 5-15% Na2O, 5-35% blast furnace slag; 2-15% Na2CO3 and 10-25% CaF2, to form abrasives.