Slaker grits from the causticising process of a pulp mill – a potential fertiliser and liming agent material for use in agriculture and forestry

Abstract

The total heavy metal concentrations in the slaker grits were clearly lower than current Finnish limit values for fertilisers used in agriculture and in forestry. This result, together with the strongly alkaline pH (13), the elevated total calcium concentration (331 g kg−1; d.w.), the existence of calcite (CaCO3), as well as the neutralising value of 39.4-% (Ca equivalents, d.w.), according to which, 0.96 tonnes of slaker grits would be required to replace 1 tonne of a commercial ground limestone product, indicate that the slaker grits are a potential fertiliser and liming agent material for use in agriculture and forestry.