Minpro Pty. Limited

Ilecard Pty Ltd

Other

Woodsreef Mines Limited

Jeremy James Lees

Murray H Pryor

John R Andrews

Phillip S Stewart

Murray Howard Pryor

Andrew J Dalzell

Process for treating coal tailings

A process for the recovery of coal particles having a maximum dimension of less than 2 mm from coal tailings including the steps of forming a slurry (101) of tailings having a pulp density of from 10 to 30% by weight; feeding the slurry into a hydrocyclone (103) to produce an underflow second stream which contains the tailing particles over a predetermined size and some of the gangue particles smaller than that size and an overflow stream containing the coal particles smaller than the predetermined size and the balance of the gangue particles, the hydrocyclone (103) being operated such that the underflow stream has a pulp density of from 40% to 60% by weight; adjusting the pulp density of the second stream, if required, to from 20 to 50% by weight; passing the repulped second stream over a rapped or vibrated sieve screen deck (105) having a wedge wire sieve screen with a radius of less than 2 m, an arc angle of from 45.degree. to 60.degree. and a slot aperture of from 80 microns to 500 microns to form a stream of coarse particles substantialy all having a particle size greater than 65 microns; and passing the course particle stream from the sieve screen deck, after repulping to a pulp density of from 20 to 50% by weight, to a spiral separator (108) for fractionation according to density to separate the coal from the gangue.

Process for recovering course particles from tailings

Classifying device

A sieve screen deck, the screen of which comprises a plurality of horizontal wedge wires connected to an array of backing bars running longitudinally of the screen parallel to its fall line. The screen is connected to a frame at its two ends, at least one end being connected by resilient means such that the screen may vibrate and flex under the influence of rapping or vibrating means. Side walls are provided along sides of the sieve screen, to prevent material flowing over sides of the screen, are also formed of a resilient material in order that they do not substantially impede the ability of the sieve screen to vibrate and flex under the influence of the rapping or vibrating means.

Sieve screen deck

A device for converting a stream of a slurry or liquid flowing down a tube into a flat stream having a uniform flow across its width and, if a slurry, a uniform particle size distribution across that width. The device comprises a vertical tube from which the slurry or liquid may flow onto a horizontal first plate in an even laminar flow and a second plate adapted to receive medium flowing over the edge of the first plate disposed below the first plate and inclined relative thereto. Metering of the amount of medium flowing onto any one increment of the width of the second plate so that it will be substantially equal to the amount of medium flowing down any other increment of equal width is achieved by the use of a first plate having a closely defined peripheral shape or by the use of vertical dividing members spaced around the periphery at uniform angular spacings which direct the medium onto equal width increments of the second plate.

Flow conversion device and method

String-like agglomerates of chrysotile asbestos fibers are recovered from crude asbestos by first forming a stable gel structure of asbestos and dispersing agent, diluting the gel structure dispersion with water in a first dilution step to form a readily pourable dispersion without dilution of the concentration of dispersing agent to a level insufficient to maintain the asbestos fibrils in a dispersed state, and then, in a second dilution step, rapidly diluting the dispersion with water to reduce the concentration of dispersing agent to a level insufficient to maintain the dispersion, thereby forming agglomerates of the fibrils. Preferably, the dispersion is subjected to an orienting flow during or immediately after the second dilution step to form string-like agglomerates.

Chemical processes

Growing community of inventors

Birchgrove, Australia

Jeremy James Lees