基于柠檬酸-改性淀粉的金川铜镍精矿降镁提质

金川镍矿石所含Cu²⁺、Ni²⁺对矿石中大量的含镁硅酸盐脉石矿物有较强的活化作用，导致镍铜混合精矿MgO含量较高，Ni、Cu品位难以提高。为实现矿山的提质降镁目标，在柠檬酸-改性淀粉药剂体系下进行了选矿试验。结果表明，在磨矿细度为-0.074 mm占90.12%条件下，采用1粗2精3扫、中矿顺序返回流程，可取得Ni、Cu品位分别为9.03%、5.18%，MgO含量6.18%，Ni、Cu回收率分别为85.30%、72.82%的镍铜混合精矿。与模拟现场工艺的实验室试验指标比较，精矿Ni、Cu品位分别提高了0.28、0.07个百分点，精矿Ni、Cu回收率分别提高了3.41、1.04个百分点，MgO含量下降了0.58个百分点。因此，在富含镁硅酸盐脉石矿物的铜镍硫化矿石的浮选中，柠檬酸-改性淀粉具有显著的提质降镁效果。

Magnesium Decrease and Quality Improvement of Nickel-Copper Mixed Concentrate in Jinchuan Based on Citric Acid-Modified Starch Combination

MgO content in the nickel-copper mixed concentrate is too high since Cu²⁺ and Ni²⁺ ions of Jinchuan nickel ore can strongly activate a large amount of Mg-containing silicate gangue minerals，and the grade of Ni and Cu is difficult to be improved.To achieve the goal of decreasing magnesium and improving quality，the dressing test was carried out under the reagent system of citric acid-modified starch combination.The results showed that，at the grinding fineness of 90.12% -0.074 mm，through the closed-circuit process of one roughing-two cleaning-three scavenging，and middlings returning in proper order into the flow，the final copper-nickel mixed concentrate with Ni grade of 9.03%，Cu grade of 5.18%，MgO content of 6.18%，nickel recovery of 85.30%，copper reovery of 72.82% was obtained.Compared with the laboratory test index of simulating in-situ process， concentrate grade of Ni，Cu is increased by 0.28 and 0.07 percentage points respectively，concentrate recovery rate of Ni，Cu is increased by 3.41 and 1.04 percentage points respectively，and content of MgO drops 0.58 percentage points.Therefore，citric acid-modified starch can significantly decrease magnesium content and improve the quality of nickel-copper mixed concentrate in copper-nickel sulfide ore，which is rich in magnesium silicate gangue minerals，flotation process.