METHOD OF REMOVING HARDNESS IONS FROM WATER Russian patent published in 1999 - IPC

FIELD: water treatment. SUBSTANCE: invention relates to waste waters, return waters, car washes, and breakthrough waters in metallurgical and chemical industries. Preliminarily, phosphate-containing reagent in quantity 120% of its stoichiometrically required quantity is added to waste water with high hardness salts' concentration. Water is then fed into purification apparatus where, in contact with mixture constituted by iron-coke galvanic couple and air oxygen at stirring, calcium, magnesium, and iron phosphates are precipitated and iron hydroxide sorbent is simultaneously formed. Purified solution containing suspended impurities is further filtered. EFFECT: simplified procedure and reduced cost. 1 tbl, 4 ex