Agglomeration potential evaluation of industrial Mn dusts and sludges based on physico-chemical characterization

Fine particles (<3 mm) are important, environmentally hazardous wastes of the mining and metallurgical industries that still contain valuable metals. Agglomeration, mainly using binders, is a common process to safely recycle those materials. This study aims at mastering cold agglomeration through understanding natural binder properties of the material. For the first time, a comprehensive physico-chemical characterization was performed on 13 samples from a manganese processing chain including ore fines. The main parameters to predict the agglomeration potential of the materials used in the present study are the presence of layer- and/or tunnel-structured phases along with the particle and grain size distribution, hardness and shapes, and particle surface charges. The Gabon ore fines show the best agglomeration potential. The soft, layer-structured plastic minerals (clays, lithiophorite) present naturally coat the hard grains (pyrolusite, cryptomelane) forming particles with enhanced binding potential. Blending these ore fines with low agglomeration potential dusts avoids binder use in the agglomeration process.