Menetelmä kalsiumsulfaattilietteen valmistamiseksi

摘要

The invention concerns a method for production of an aqueous sludge of calcium sulfate in dihydrate form with the desired particle size distribution, in which an aqueous calcium sulfate sludge in dihydrate form is ground in the presence of a dispersing chemical to a fine particle size, the obtained product also containing an undesired fine material fraction, and the undesired fine material fraction is removed from said product by recrystallization and the particle size distribution in the aqueous sludge of calcium sulfate in dihydrate form obtained after grinding and crystallization is stabilized with the desired particle size distribution. According to the invention it is also possible to proceed so that the calcium sulfate in dihydrate form is dry ground to a fine particle size, whereupon the ground product is suspended in water, in which the undesired fine material fraction is removed from the product by recrystallization.