Reagent precipitation of hardness ions by carbonate-containing builders

Abstract

Phase composition of carbonate containing builders obtained by neutralization of proton containing reagents with sodium carbonate is investigated. Itis shown that the builders are a mixture consisting mainly of Na[2]CO[3] · NaHCO[3] · 2H[2]O, Na[2]CO[3] · H[2]O and salts of the corresponding acids. The mixture is able to reduce total water hardness with 3.9 to 1.6–1.7 mmol-eq·l{ -1}. It is found that the builders containing Na[2]CO[3] · NaHCO[3] · 2H[2]O, Na[2]CO[3] · H[2]O and CH[3]COONa · 3H[2]O remove hardness as well as Na[2]CO[3], Na[3]PO[4] ·12H[2]O and STPP at the same flow rate.