Improvements in the manufacture of superphosphate
Реферат: 531,298. Calcium superphosphate. EVERY, C. E. (Akiebolaget Kemiska Patenter). July 17, 1939, No. 20774. [Class 1 (iii)] Superphosphate is prepared by mixing all or part of the sulphuric acid with part only of the raw phosphate, separating calcium sulphate and the insoluble residue by decanting, filtering, or centrifuging, and acting on the rest of the raw phosphate with the solution. Preferably the ratio of sulphuric acid to phosphate in the first stage is 1.5 : 1 to 3 : 1, the concentration of the acid is below 67 per cent. H 2 SO 4 , and the calcium sulphate &c. is removed by a band filter. After the first reaction, the concentration of sulphuric acid may be increased by addition of stronger acid.
Improvements in the process of manufacture of hexamethylene diisocyanate
Номер патента: GB833467A. Автор: . Владелец: SOLVAY SA. Дата публикации: 1960-04-27.