Method for estimating quantity of non-hydrated cement in a cement recycling system

The objective of this research was to develop a method for the rapid estimation of the quantity of residual cement in sludge water and to control its hydration reaction using sodium gluconate in order to enable the residual cement in sludge water to be effectively utilized. The quantity of residual cement in sludge water can be estimated by measuring the heat of hydration liberated in 24 h using a conduction calorimeter. It is possible to recommence sodium gluconate-controlled cement hydration using magnesium nitrate. A method was developed to simulate the rate of the hydration reaction, which makes it possible to estimate the quantity of residual cement in sludge water by measuring the rate of heat liberation of hydration over 10 h.