Anhydrous sodium bisulphate produced from - sulphuric acid and sodium sulphate

摘要

Anhydrous NaHSO4 is produced in an aq. soln. of 60 wt.% H2SO4 and 7% Na2SO4 at 70-80 degrees C, cooling to 25-40 degrees C and calcining the separated crystal mixt. in the pres. of Na2SO4 with hot air at 120-130 degrees C. The product contains e.g. 80% NaHSO4 and 0.35% H2O. 2-5% Silica gel may be added as anticaking agent. Corrosive HCl is eliminated from usual processes. In an example, H2SO4 (326 kg) and Na2SO4 (474 kg) are added to 1600 l. of an aqu. soln. of 60% H2SO4 and 7% Na2SO4. The suspension was heated to 70-80 degrees C and cooled to 40 degrees C. Na2SO4 (200 kg) was added to the above solid product (800 kg) at 40 degrees C and calcined for 8 hrs. at 120-130 degrees C. The product contained 80% NaHSO4 and 0.35% H2O.