METHOD OF PRODUCING ANHYDRITE BINDER Russian patent published in 2024 - IPC C04B11/06 C04B11/26 

FIELD: chemistry.

SUBSTANCE: invention relates to production of anhydrite binder from acidic calcium sulphate wastes from hydrogen fluoride production and can be used to produce materials and structural articles for the construction industry. From a batch of crushed technogenic fluoroanhydrite with a particle size of 40-80 mcm, which is a waste of hydrogen fluoride production of an enterprise, 7.0 g is sampled, a control measuring cylinder with diameter of 17 mm and height of 20 mm is moulded from it under pressure of 10-12 MPa. Then, on carbon-graphite electrodes, diametrically mounted in the mould die with the control measuring cylinder located in it, AC voltage is supplied, increasing from 0 to the value at which current in the circuit with the control measuring cylinder is equal to 0.1 A, and the voltage value is fixed at the current value of 0.1 A. Comparing the recorded voltage value with the data of the nomogram of the voltage dependence on the amount of sulphuric acid in the man-made fluoroanhydrite, which is a production waste of the enterprise, obtained for at least seven separate reference cylinders from the man-made fluoroanhydrite of the enterprise, obtained under the same conditions, actual content of sulphuric acid in the control measuring cylinder is determined. Then the amount of sulphuric acid additive required to bring its content to 15 wt.% over 100 wt.% of the batch of technogenic fluoroanhydrite is calculated. With thorough mixing, a calculated amount of sulphuric acid additive is added to a batch of technogenic fluoroanhydrite, and over 100 wt.% of the obtained mixture is added 10-15 wt.% of a neutraliser in form of quicklime or slaked lime, and 1.0-1.5 wt.% potassium sulphate is added as setting accelerator.

EFFECT: obtaining anhydrite binder from technogenic fluoroanhydrite with specified compression strength of not less than 10 MPa.

1 cl, 1 dwg, 1 tbl, 3 ex