Limestone and dolomite powder as binders for wood ash agglomeration

Limestone and dolomite powder were tested as binders during wood ash agglomeration on an industrial and a laboratory scale. Two agglomeration methods are compared. Dolomite from Estonia is commonly used as a binder/additive during automatic production of agglomerated wood ash at the central heating plant of Kalmar, Sweden. Swedish limestones from Öland and Ignaberga as well as Swedish dolomite from Glanshammar were used as binders in the production of test agglomerates of wood ash. The chemical and mineralogical composition of the binders as well as of the resulting granules and pellets is presented. The structural, chemical and leaching properties of the hardened ash/binder agglomerates are discussed in relation to their possible environmental impact on forest soil. The environmental acceptance of recycling of agglomerated ashes to forest soils is also discussed in relation to the new recommendations.