Vermiculate Concentrate Pre-crushing for Firing in Electric Furnaces

Abstract

AbstractThe expanded vermiculite is widely used in many spheres of life. So, the great attention is paid to the vermiculite baking and to the technological preparation of concentrates. The preliminary preparation of concentrates includes not only grinding large particles to a size of about 5 mm, but also additional “narrow-band” fractioning of the original concentrates. Only granulometric homogeneous streams of vermiculite concentrates make it possible to carry out cost-effective firing without unnecessary energy costs, but also provide the highest quality of the expanded product at the exit from the furnaces. The need for grinding the row material is made by the severely expressed granulometric heterogeneity in all size groups of concentrates. The spread in the sizes of the nominal particle diameters can be fourfold, that is, for example, from 2 to 8 mm. The article reviews chopping units for grinding large-sized particles of vermiculite concentrates. The calculation of dynamic characteristics of the chopping process is carried out. The use of the dynamic characteristics to provide technological preparation of concentrates for thermal treatment of vermiculite in electric furnaces is being proved. The specificity of the designs of electric modular-furnaces and furnaces with movable base platforms is that due to the narrow slot-like firing space, high energy efficiency of such furnaces is achieved, which makes them competitive and safe, in contrast to furnaces operating on hydrocarbon fuel.