Development of the Selective Hydrophobic Coagulation process. Fifth quarterly technical progress report, October 1, 1992--December 30, 1992

Abstract

A novel technique for selectively coagulating and separating coal from dispersed mineral matter has been developed at Virginia Tech. The process, Selective Hydrophobic Coagulation (SHC), has been studied since 1986 under the sponsorship of the US Department of Energy (Contracts AC22-86PC91221 and AC22-90PC90174). The SHC process differs from oil agglomeration, shear or polymer flocculation, and electrolytic coagulation processes in that it does not require reagents or additives to induce the formation of coagula. In most cases, simple pH control is all that is required to (1) induce the coagulation of coal particles and (2) effectively disperse particles of mineral matter. If the coal is oxidized, a small dosage of reagents can be used to enhance the process. During the quarter, the Anutech Mark IV surface force apparatus was used to generate surface force-distance data for the mica/dodecylamine hydrochloride system (Task 2.1.1). Work to characterize the hydrophobicity of this system and the mica/DDOA{sup {minus}} system was also initiated (Task 2.1.2). In Task 3, the mixing/coagulation characteristics of a small Kenics static mixer/agitation system have been investigated (Task 3.2.1), a lamella thickener for the recovery of coagula has been built (Task 3.3.1), and the test program for the recovery of coagula by column flotation has been initiated (Task 3.3.4).