By my improved process now to be described I have done away with the necessity for any mechanical mixture of the ingredicuts and instead prepare lithopone ofany desired grade and in much purer form by a simple process or reaction, which at the same time produces some by-product of marked commercial value and one, preferably, that is easily soluble in water.

I have found that if the acid titanium cake is first slowly added to the barium sulphide solution and rapidly stirred, this discoloration will be avoided in the'sub sequent steps em loyed inthe manufacture of lithopone.