METHOD OF PURIFYING ETCHING SOLUTION OF HYDROCHLORIC ACID AND RECYCLING WASTE SLUDGE Russian patent published in 2024 - IPC C23G1/36 C02F1/52 C02F11/00 C02F11/12 

FIELD: various technological processes.

SUBSTANCE: invention relates to the technology of etching production of etching plants, and in particular to a method of purifying etching solution of hydrochloric acid and recycling waste sludge. Etching solution is fed into the first mixing tank with addition of the coagulant, and then into the second mixing tank where the flocculant is added. Further, the etching solution enters the settling tank, in which stratification takes place. Upper layer of the purified etching solution enters the acid circulation tank. Formed sedimentary sludge under action of gravity is deposited on the bottom of the settling tank and is lowered into the neutralizing tank. At the same time at the bottom of the settling tank there is a pipe for removal of sludge under static pressure. Alkali is added to neutralizer tank. After neutralization, sludge is supplied for dehydration and drying.

EFFECT: reduction of technological process, saving of steam and cooling water consumption, reduction of capital investments into equipment and reduction of occupied area, saving of costs for electric power, facilitation of further processing and transportation of wastes.

9 cl, 1 dwg