New Flotation Flowsheet for Treatment of Fankou Complex Lead-Zinc Ore

摘要

Fankou mine has a large and rich polymetallic deposit in which the principal economic minerals are galena, sphalerite and pyrite, calcite, dolomite and quartz being the major gangue minerals. The ore contains about 5% lead, 11% zinc and 25% sulphur; it also contains silver, germanium, etc., which are recoverable as by-products during the metallurgical treatment of the lead and zinc concentrates. Because of the very fine intergrowth of the sulphide and refractory minerals several years of research work have been spent to obtain an efficient flotation flowsheet and reagent regime to ensure the successful separation of galena, sphalerite and pyrite. The main features of the flowsheet are primary grinding of the ore followed by bulk flotation of the sulphides from the gangue and fine regrinding of the bulk concentrate prior to differential flotation of galena, pyrite and sphalerite in a high alkaline medium. To enhance the selectivity of lead-zinc separation and reduce the consumption of reagents, a dithiono-carbamate collector is used in the lead circuit. Results from pilot tests are promising. The lead recovery is 83.8% with a concentrate grade of 63.1% Pb and zinc recovery is 93.1% at a grade of 51.0%. The tailings of the differential flotation are the pyrite products containing 36.7% sulphur at a recovery of 73.0%.