Cobalt Violet Pigment Production
Cobalt violet pigment is an aqueous solution of ammonium cobalt sulfate and ammonium phosphate, precipitated each made. The resulting purple precipitate ammonium cobalt violet, after bleaching, filtration, drying, crushing derived products.
Cobalt violet with ammonium phosphate is disodium hydrogen phosphate, cobalt violet with sulfuric acid solution was added to a solution of disodium hydrogen phosphate, terminal PH value of 8 to 8.5 with 50 ℃ hot water rinsing, filtration, drying and pulverizing. Cobalt phosphate octahydrate prepared was added to muffle calcination dehydration. Calcination temperature was controlled at 800 ℃, calcined for 3 hours, and the calcination temperature is too high, although the firing time can be shortened, but easy sintering, and therefore should not exceed 900 ℃. Calcined charge purple, triturated through cooling, filtering, drying, crushing derived products. Manufacture of phosphoric acid per 100kg cobalt violet consume about 170kg of cobalt sulfate heptahydrate.