GB450044A - A process for the preparation of coal by flotation - Google Patents

Abstract

Coal is separated into its reactive and inert constituents by disintegrating the coal to a degree sufficient to release the two types of constituents, forming the disintegrated coal into a slime with water and a soluble oxidizing agent such as nitric acid, sulphuric acid, hydrogen peroxide, or potassium permanganate, and then floating off the inert constituents by the addition of a p frothing agent such as phenol, aniline, or alcohol. The reactive constituents are subsequently floated with the aid of a known coal collector such as coal tar oil. The action of the oxidizing agent in temporarily inhibiting the flotation of the reactive constituents may be reinforced by the addition of an aliphatic or aromatic hydrocarbon compounds having several terminal groups, such as COOH, NH2CO, or OH, possessing an affinity for water, e.g. hydroquinone, or by the addition of humic acid, lignin sulpho acid, or their derivatives, e.g. cellulose sulphite lye. To release the reactive and inert constituents, the former comprising the humins and bitumens, it is usually necessary to grind the coal to a greater extent than that necessary to free the petrographic constituents, viz. anthracite, dull coal, and fibrous coal. The separation of a pure dull coal into reactive and inert constituents is described.