METHOD OF CONTROLLING AGITATION LEACHING OF SILICA-CONTAINING CAKE BY RECYCLED SOLUTION Russian patent published in 1997 - IPC

FIELD: mining industry. SUBSTANCE: invention relates to wasteless processing of alkali aluminosilicates, in particular, hydrochemical processing of silica-containing cake. Slurry obtained after leaching by recycled solution is sorted to produce coarse- and fine-grain slurry. The former is repulped with hot water and conveyed to aftergrinding and the latter is submitted to concentration with formation of aluminate solution and sludge. The sludge is mixed with hot water, then with slurry after aftergrinding and concentrated separating washed sludge and poor washing water which is used to wash sludge and produce reach washing water. The latter is mixed with soda-alkali and soda solutions to produce recycled solution used to leach cake. Method involves continuously measuring intake of recycle, soda, and soda-alkali solutions, washing water, hot water to wash sludge, hot water to wash and repulp coarse-grain slurry, density and temperature of slurry after leaching, the same of aluminate solution, density of sludge before aftergrinding, alkali content in coarse-grain slurry before and after repulping and in washed sludge. Periodically measured are contents of aluminium and alkali metal oxides and alkali carbonates in fine-grain slurry as well as aluminium oxide and sodium hydroxide in aluminate solution. Stabilized are ratios of soda-alkali and soda solution intakes to washing water intake and that of recycled solution to cake consumption. Density of slurry after leaching is also stabilized. Basing on predictive models, one can determine composition of slurries and solutions from contents of aluminium and alkali metal oxides, alkali carbonates, and solid phase. Intake ratios found are adjusted in order to achieve preset values of caustic modulus, contents of carbonate alkali and aluminium oxide in solutions and slurries. Basing on periodical measurements of chemical composition, predictive models are corrected. EFFECT: optimized process control. 3 cl, 1 dwg