| 摘要 |
<p>1,186,204. Froth flotation. D. WESTON. 28 April, 1967 [13 May, 1966; 18 May, 1966; 11 July, 1966], No. 19645/67. Heading B2H. In a process for the separation of metallic oxides from metallic oxide-containing materials by froth flotation, without the need for any desliming prior to flotation, a pulp containing the material in effectively dispersed state is treated with a collecting agent to effect activation of the metallic oxide values of the material. The pulp is conditioned at an ap- ,propriate pH to initiate flocculation of the metallic oxide values. The pH of the resulting pulp is then adjusted to a value suitable for further flocculation and for flotation of the metallic oxide values and is conditioned at the adjusted pH value to effect further flocculation of the metallic oxide values and dispersion of the gangue of the material in the pulp. The pulp is then finally subjected to a flotation process to recover the metallic oxides. The initial effective dispersion may be achieved without the addition of a dispersing agent over a range of pH's and conditioning times. Alternatively, dispersion requires careful control of pH, conditioning time and addition of a dispersing agent, e.g. sodium silicate, sodium hydroxide, lignin sulphonate or silicon tetrachloride. Where initial dispersion is carried at an alkaline pH, recovery of the metallic oxides is improved by the addition of an electrolyte, e.g. sodium fluoride, sodium sulphate or sodium chloride. Suitable collecting agents include fatty acids or the combination of a fatty acid with petroleum sulphonate and/or fuel oil, the fuel oil acting as a modifying agent. PH adjusters may include sulphuric acid, sodium silicate or sodium hydroxide. The flotation circuit may consist of a rougher stage followed by a number of cleaning stages either without or with conditioning between some or each of the stages using a dispersing agent. Carbonates which tend to float with the metallic oxides in the later stages of cleaning may be depressed by lowering the pH of the pulp to acid and conditioning with sodium fluoride. Where a wet grinding circuit precedes the flotation circuit, the dispersing agent and/or the collecting agent may be added directly to the grinding circuit. A wetting agent may be added to the pulp in the grinding circuit. Examples of four-stage conditioning cycles and of comparative tests carried out on iron ores and uranuim ores are given. The process is also applicable to the treatment of materials already in comminuted or naturally finely divided condition, e.g. tailings, slimes, beach sands or clays containing, for example, vanadium oxides.</p> |
