Preparation of Concrete Plasticizer from Corncob Residue of Enzymatic Hydrolysis

Corncob residue from enzymatic hydrolysis of preparing bio-ethanol was modified and separated by the process of alkaline sulfite pulping(ASP) and the lignosulfonate used as concrete plasticizer was obtained in this process.Results show that the optimum reaction conditions are: alkali dosage 14%(Na2O),degree of sulfitation 75%～85%,temperature 155℃,time 3～3.5 h.Under these conditions,the performance of lignosulfonate is as follows: yield 51.39%,fluidity of cement paste 112 mm when the lignosulfonate dosage was 0.35%(solid),surface tension 46.4 mN/m,content of sulfonate group 1.89 mmol/g.