Recycling of sand sludge as a resource for lightweight aggregates

This paper reports the results of investigations on manufacturing lightweight aggregate from sand sludge. Sand sludge is a waste product from crushing and screening plants for sand and gravel production. Preliminary studies demonstrate the feasibility of recycling sand sludge into lightweight aggregates. The properties of lightweight aggregates from sand sludge depend on both, the preliminary firing temperature of the frit and the foaming temperature of the green granules. Increasing the firing temperature of the frit from 800 to 900 °C, the compressive strength, and the bulk and relative density of the granulated foam material decrease on the average by a factor of two, the water absorption decreases by 1%. The lightweight aggregates, derived from sand sludge at a temperature of 950 °С, have a bulk density of 330 kg/m3, a compressive strength of 0.18 MPa and a water absorption of 0.1%.