Practice and Application of Regrinding and Re-election of Swept Concentrate from a Low-grade Difficult Gold Ore in Qinghai Province

This is an article in the field of mining processing engineering. The gold grade of a low-grade, high-arsenic, high-carbon refractory gold ore in Qinghai is about 2.38 g/t, and the industrial recovery rate of gold is about 77%. Through process flow investigation and mineralogical analysis, the gold grade of the mine's concentrator scavenging concentrate is about 3～6 g/t. The main gold-bearing minerals, arsenopyrite and pyrite, have low dissociation degrees of 76.23% and 78.74%, respectively. When floated separately, the gold recovery rate is about 30%～50%. In order to further improve the recovery rate of gold in this refractory gold mine, the mine conducted laboratory simulation of the process flow of the concentrator to carry out the experimental study of regrinding and re-separation of the scavenging concentrate, formulated the process flow scheme of returning the scavenging concentrate to the second stage grading pump pool in a centralized manner, and completed the process technology improvement design and process technology improvement practice of the concentrator. The production application results after the technological transformation showed that the single dissociation degree of the main gold-bearing minerals, arsenopyrite and pyrite, increased to 78.03% and 80.63% respectively when the scavenging concentrate was returned in a centralized manner, compared to the sequential return. The regrinding and re-separation process of the scavenging concentrate did not affect the grade of the concentrate under the premise of centralized return. The recovery rate of gold in the concentrator was increased from 77.14% to 81.13%, effectively improving the gold recovery index of this refractory gold mine.