Flocculants and Modifiers for More Efficient Flotation and Processing of Coal Sludge

Abstract

Improvement in the efficiency of sludge flotation and processing in coal enrichment by appropriate selection of flocculants and modifiers is considered. Zh coal fines (with a high content of small classes) from the Chertinsk mine (Kuznetsk Basin) enriched at Belovskaya enrichment facility are investigated, with 19.5% ash content. The flocculants employed are acrylamide copolymers: Magnаfloc 380 (М-380), Magnаfloc 10 (М-10), Magnаfloc 525 (М-525), and Magnаfloc 345 (М-345). Their performance is compared with that of widely used flocculants (VPK and KSP polyelectrolytes and Technofloc-TL 1597). Neonol (oxyethylated nonylphenol), which is an effective modifier, is also employed; it consists of a mixture of isomers. The action of flocculants and the subsequent modifier on the coal fines is analyzed on the basis of theoretical and experimental data. Sedimentation analysis shows that anionic Magnаfloc М-10 is the most effective flocculant for positively charged coal dispersions. The flotation efficiency is improved for coal fines treated with Magnаfloc М-10 and then Neonol modifier. Quantum chemical modeling by means of HyperChem software establishes the interaction of Neonol with the polar centers of model compounds in the coal’s organic mass (forming hydrogen bonds) and with the polar centers of Magnаfloc М-10. Analysis of the coal’s flotation properties confirms that the coal surface becomes hydrophobic after flocculation of the coal fines and subsequent treatment with Neonol modifier. After flocculation of the coal sludge and subsequent treatment with Neonol, the concentrate yield in flotation is increased by 2.4%, while its ash content is decreased by 0.3%.