Lime sludge classification

There is interest in lime sludge classification in both wastewater and potable water treatment plants. If the magnesium hydroxide content of a lime sludge can be suitably reduced, the residual calcium carbonate can be recalcined to calcium oxide. Too much magnesium hydroxide will prevent the slaking of the lime. The restrictions and rising cost of disposal of spent lime makes recovery and recycling attractive. 

In the decanter separation process, it is required to obtain high calcium carbonate recovery, say above 80%, while keeping magnesium hydroxide recovery (in the cake) as low as possible, say below 50%. 

Finure 6.9. Graph - Recovery v Feed Rate (Pond 14 3) - Lime Sludge Classification. 

Data for this work are tabulated in Table A. 3 of the Appendix. 

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Table A.3 Lime sludge classification data used in Section 6.4.3...

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