VERFAHREN ZUM AUFBEREITEN VON ROTSCHLAMM

摘要

Red mud obtd. as a residue from alumina prodn. by the Bayer method is suspended in water together with burnt lime and substances contg. humic acid or its derivs. (coal, brown coal, peat etc). whereby most of the alkalis contained in the red mud pass into the soln. in the form of alkali humates. The soln is then separated from the solids and can be utilised for the prodn. of alkali carbonates, alkali hydroxides and/or a fertiliser. The solid carbonates, which contains 1.5% of alkalis can now be utilised for the prodn. of iron by reduction and smelting. The remaining slag can be used for the prodn. of cement, opt. after leaching out the residual alumina, which can be recovered. The reduction of the alkali content of the red mud below 1.5% makes it possible to utilise the red mud in the above way on a large scale.