Calcium sulphate hemihydrate filtration preventing calcium sulphate - incrustation on apparatus

摘要

Sludge containing calcium sulphate hemihydrate is filtered by feeding the sludge to a filter, filtering, removing the sludge, and washing the filtering, removing the sludge and washing the filtration apparatus with an alkali carbonate, after which more sludge is led to the filter. The carbonate solution may be 1-20; Na2CO3, K2CO3, or (NH4)2CO3. There may be a water wash before, or both before and after, the carbonate wash. Used to prevent deposition and incrustation of calcium sulphate on the filtration apparatus.