FIELD: chemical industry.
SUBSTANCE: method is proposed for the production of sulphuric acid and cement clinker using calcium sulphate, which is formed and separated as a by-product during the interaction of phosphate with sulphuric acid to obtain phosphoric acid. The method includes treating calcium sulphate separated from phosphoric acid with an inorganic acid to obtain a suspension containing purified calcium sulphate, separating the purified calcium sulphate in the solid state from the liquid phase of the obtained suspension. The resulting calcium sulphate is mixed with additives and reducing agents to obtain a mixture containing raw meal to produce cement clinker, which is fired to produce cement clinker and form sulphur dioxide in the exhaust gas. The resulting sulphur dioxide is purified from the exhaust gas and sulphur dioxide is supplied as a raw material to the sulphuric acid production process. Purification of sulphur dioxide includes dry deposition of particles larger than 100 mcm, wet deposition of solid particles having a size in the range from 20 to 100 mcm, removal of particles having a size of less than 20 mcm, and removal of nitrogen oxides.
EFFECT: invention makes it possible to ensure the recovery and circulation of sulphur dioxide in the production of sulphuric acid and cement clinker with integration into the production of phosphoric acid, to reduce the impact of phosphogypsum deposits and gas emissions on the environment.
13 cl, 3 dwg
