Adsorption of comb -type superplasticizers on calcium carbonate in alkaline medium in presence of electrolytes and rheological properties

Adsorption behaviour of polycarboxylate type superplasticizers (PC) on CaCO 3 suspension in a basic medium has been studied in the presence of NaCl, Na 2 SO 4 and CaCl 2 having same ionic strength. The amount of PC adsorbed was found out by determining the amount of PC present in supernatant solution with the help of total organic analyzer. It is found that the adsorption decreased when the POE chain length decreased. The adsorption was increased in presence of CaCl 2 while NaCI and Na 2 SO 4 decreased the adsorption. The adsorption is not a competitive process but depends on ionic strength. Rheological measurements of suspensions have also shown that lower the POE chain length, higher the viscosity of the CaCO 3 suspension.