High Hydrophobic Arsenic Difficult Separation Gold Ore Dressing Technology Was Studied

The thick disseminated grain size and thin ones of the gold of a sulfur-gold ore are irregular, and fine-grain gold are predominant and are respectively encapsulated in pyrrhotite, pyrite and arsenopyrite, in which arsenopyrite are mainly gold carriers. On the spot, gold concentrate with high arsenic are gained by conventional flotation firstly, secondly the tailings of gold are used to recover pyrrhotite by magnetic dressing, lastly sulfur concentrate is obtained by flotation from magnetic tailings, but arsenopyrite is not recovered, which lead to the loss of the fine-grain gold in arsenopyrite, besides sulfur concentrate was gained with high arsenic. That is bad for the price and sales of concentrates and has a strong impact on economic performance of enterprises because of low recovery of gold and quality of concentrates.The paper’s main aim is to reduce the arsenic content of gold concentrate, increase the quality of gold concentrate and the gold recovery with due consideration to improve the quality of sulfur concentrate. The thesis adopted amain-process stream of magnetic-flotation, the part of Au recovery using the flowsheet of speed flotation and the part of S-As separation using selective flotation. And Au recovery was improved by the two ways, for one thing, to improve the recovery of Au flotation, a flowsheet of magnetic-flotation was adopted, namely, pyrrhotite was firstly recovered by magnetic and then Au was flotation. Using this flowsheet can not only improve the feed grade of gold ore, which is helpful to increase the quality of gold concentrate, but also can save the reagent usage of Au flotation. Besides, the flowsheet of speed flotation can recover gold with good floatability early and largely, and avoid the gold floatability of this part becoming bad because of over circle during flotation operation. For another thing, the gold carriers-arsenopyrite was recovered to improve the recovery of gold by the separation of pyrite and arsenopyrite. The pyrite and arsenopyrite was separated effectively with waste acid containing copper instead of sulfuric acid and Y-As as the depressor. The loss of gold in tailings was reduced and the recovery was improved through recover the fine-grain gold in arsenopyrite. Besides, the quality of sulfur concentrate was improved because of reduction of the arsenic content.By the closed circuit experiment, the weighted gold concentrate with21.22g/t Au,0.69%As and51.99%of Au recovery was obtained for the part of flotation, the arsenic concentration with gold was gained with10.22g/t Au and18.51%of Au recovery, and the loss of gold in tailings was only4.99%. Comparing with the flowsheet of flotation-magnetic-flotation of the plant, the recovery was increased22.66%and the loss in tailings was reduced15.41%, the arsenic content of Au and S concentrate was reduced0.36%and0.13%, respectively. Therefore, by improving the flowsheet of plant, the Au recovery and the quality of concentrate was greatly increased, besides the cost of reagent was obviously saved, so a good economic benefit was gained.