Patent GB-1434545-A (GB)
Title: Ore beneficiation
IPC: B03B13/04
Filed: 1973-09-12
Abstract: 1434545 Flotation treatment of ores EARTH RESOURCES CO 12 Sept 1973 [12 Sept 1972] 42955/73 Heading C1A [Also in Divisions B2 C7 and G3] A process for separating by flotation the mineral values and gangue of an ore comprises the steps of forming a slurry of the ore, adding beneficiating chemicals including a flotation agent to the slurry, determining the range of oxidation-reduction potentials of the slurry that will give optimum separation of he gangue and mineral values, controlling the supply of beneficiating chemicals to the slurry to maintain the oxidation-reduction potential of the slurry within said range, and separating by flotation the mineral values from the gangue. Fig. 2 illustrates a flotation installation in which the feed of beneficiating chemicals to the ore slurry is automatically controlled. Coarse ore fragments are crushed in water in a ball mill to form a slurry. The slurry is passed through a classifier to remove oversize particles which are returned to the mill while the slurry containing fine ore particles is fed from the classifier via lines 30, 32 to primary, e.g. Maxwell, flotation cells 34, 36 which are connected to secondary, e.g. Fagergren, flotation cells 52, 54, 68 arranged in series. A solution of beneficiating chemicals is fed to the flotation cells 34, 36, 52 and 54 from a tank 92 by a pump 96 via lines 98, 74, 78 and valves 39, 41, 76, 80 controlled by solenoids 84, 90, 104, 108 respectively. The oxidation-reduction potential of the slurry in each flotation cell is the E.M.F. of an electrolytic cell, e.g. 42, having its, e.g. calomelplatinum, electrodes dipping in the slurry in the respective flotation cell, e.g. 34, and connected via a voltmeter, e.g. 47, to the solenoid, e.g. 84. When the oxidation-reduction potential of the slurry exceeds a selected range, found by a series of previous tests to be optimum for the efficient flotation of the mineral values desired, the E.M.F. produced by the electrolytic cell is sufficient to energize the solenoid which in turn causes its associated valve to close; similarly, when the oxidation-reduction potential falls below the selected range, the solenoid is deenergized causing the valve to open and admit more beneficiating chemical solution to the respective flotation cell. A flotation installation with manually controlled feed of beneficiating chemical is also described. The process is particularly suitable for the froth flotation separation of naturally occurring copper sulphide and other sulphidable copper compounds present in a copper ore. A sulphiding agent, e.g. hydrogen sulphide, an alkali metal hydrosulphide or an alkali metal sulphide, is added to the ore slurry to react with the particles of the sulphidable compounds to form a sulphide coating on the surfaces of the particles. The coated surfaces allow wetting with a selective sulphide flotation agent. The other beneficiating chemicals which are added to the slurry include a flotation agent, e.g. an alkyl xanthate or aerofloat, and a flocculant. The process is also applicable to the flotation separation of other metallic ores, e.g. those containing A, Pb, Zn, Mo, Mn, Co or Cd.