a continuous preparation of calcium hydroxide slurry can be made on a mobile apparatus that uses an eductor to initially combine metered flows of calcium oxide and water . the calcium hydroxide slurry is retained in a deaerating sump and then pumped into a serpentine centrifugal mixer so that the reaction of the calcium oxide and the water is safely complete . because the apparatus allows the calcium hydroxide slurry to be recirculated into the deaerating sump , the slaking process can continue even when it is necessary to pause the discharge of slurry to change transport tankers .