In this work, different flotation–preoxidation–cyanidation methods are considered for treating a lowgrade refractory gold ore. On the one hand, the results of selective flotation show that 22% and 31.1%of total Sb a...In this work, different flotation–preoxidation–cyanidation methods are considered for treating a lowgrade refractory gold ore. On the one hand, the results of selective flotation show that 22% and 31.1%of total Sb and As, respectively, remained in the final tailings and only about 28% of the total Au remained for further cyanidation processes. On the other hand, in bulk method of flotation the maximum Au recovery of 90.6% achieved after 60 min of flotation at the grind size with K80 of 146 micron. In addition, the bulk flotation method resulted in the concentrate with low concentrations of Sb and As elements. To improve the recovery of low-grade refractory gold ores, flotation should be followed by roasting, biological, or pressure oxidation processes so that the gold could be liberated prior to cyanidation processes. It is also found that the pressure oxidation pre-treatment of the concentrates prior to cyanidation may yield high gold recoveries of over than 83%. In these processes, recoveries are controlled by the temperature and the oxygen partial pressure in the solvent. However, by utilizing the bio-oxidation technique, the oxidation of sulfur to sulfate cannot be completed and, consequently, the gold recovery may be limited to only 72.2%.展开更多
This review summarized the recent advances in the utilization of nonmetallic minerals and their applications for fabrication of unfired refractories.The preparation of refractory powder utilizing cheap nonmetallic min...This review summarized the recent advances in the utilization of nonmetallic minerals and their applications for fabrication of unfired refractories.The preparation of refractory powder utilizing cheap nonmetallic minerals of zircon,low-grade bauxite and quartz was discussed,respectively.The preparation of three unfired SiC-based refractories：SiC-SiAlON-ZrN,Al2O3-SiC/β-SiAlON/Ti（C,N）-C,and Al2O3-SiC-Si3N4 using the as-prepared refractory powders was introduced.展开更多
By mineral liberation analyzer （MLA） automated quantitative system, the niobium-tantalum ore in this study was classified as refractory mineral of low-grade which was mainly composed of fergusonite, polycrase, ilmen...By mineral liberation analyzer （MLA） automated quantitative system, the niobium-tantalum ore in this study was classified as refractory mineral of low-grade which was mainly composed of fergusonite, polycrase, ilmenorutile, and bastnasite. Most of niobium and rare earth metals were dis- seminated in these minerals （particle sizes of 95 % rare earth elements 〈40 μm）, which cannot be concentrated through traditional floatation process and treated by the current hydrofluoric acid leaching in industry application. It is nec- essary to develop a new approach to recovery these valuable metals. In this study, an improved method is proposed to extract these metals, which includes acid roasting and sulfuric acid leaching. The influence of mineralogy, acid concentra- tion, leaching temperature, leaching time, and liquid to solid ratio was experimentally studied. It is observed that after the ground ore （-74 μm） was roasted at 350 ℃ for 2 h with sulfuric acid （18.4 mol.L- 1） in the ore to acid mass ratio of 1：1, and then the roasting residue reacted with 25 % sulfuric acid at 90 ℃ for 2 h, the recovery rate of rare earth elements reaches 〉90 %, and the leaching extent of niobium can reach 84 %.展开更多
针对云南某细粒难选赤褐铁矿石含磷超标,须提铁降磷方能利用,但采用常规的强磁选、重选、浮选方法均无效果的情况,采用焙烧—浸出新工艺及自行研发的浸出剂,在焙烧温度为1 000℃、焙烧时间为15 m in、浸出剂浓度为10%、浸出液固比为3∶...针对云南某细粒难选赤褐铁矿石含磷超标,须提铁降磷方能利用,但采用常规的强磁选、重选、浮选方法均无效果的情况,采用焙烧—浸出新工艺及自行研发的浸出剂,在焙烧温度为1 000℃、焙烧时间为15 m in、浸出剂浓度为10%、浸出液固比为3∶1、浸出时间为5 m in条件下,获得了精矿铁品位为66.43%、磷品位为0.131%、铁回收率为98.89%的理想指标,目前正开展工业试验。试验结果为难选铁矿资源的开发利用提供了新的思路。展开更多
文摘In this work, different flotation–preoxidation–cyanidation methods are considered for treating a lowgrade refractory gold ore. On the one hand, the results of selective flotation show that 22% and 31.1%of total Sb and As, respectively, remained in the final tailings and only about 28% of the total Au remained for further cyanidation processes. On the other hand, in bulk method of flotation the maximum Au recovery of 90.6% achieved after 60 min of flotation at the grind size with K80 of 146 micron. In addition, the bulk flotation method resulted in the concentrate with low concentrations of Sb and As elements. To improve the recovery of low-grade refractory gold ores, flotation should be followed by roasting, biological, or pressure oxidation processes so that the gold could be liberated prior to cyanidation processes. It is also found that the pressure oxidation pre-treatment of the concentrates prior to cyanidation may yield high gold recoveries of over than 83%. In these processes, recoveries are controlled by the temperature and the oxygen partial pressure in the solvent. However, by utilizing the bio-oxidation technique, the oxidation of sulfur to sulfate cannot be completed and, consequently, the gold recovery may be limited to only 72.2%.
基金supported by the National Natural Science Foundations of China ( 51032007,51372232,and 51472222 )the Research Fund for the Doctoral Program of Higher Education of China ( 20130022110006 )the Beijing Higher Education Young Elite Teacher Project ( YETP0636)
文摘This review summarized the recent advances in the utilization of nonmetallic minerals and their applications for fabrication of unfired refractories.The preparation of refractory powder utilizing cheap nonmetallic minerals of zircon,low-grade bauxite and quartz was discussed,respectively.The preparation of three unfired SiC-based refractories：SiC-SiAlON-ZrN,Al2O3-SiC/β-SiAlON/Ti（C,N）-C,and Al2O3-SiC-Si3N4 using the as-prepared refractory powders was introduced.
基金financially supported by the National Science & Technology Pillar Program(No.2012BAB10B00)
文摘By mineral liberation analyzer （MLA） automated quantitative system, the niobium-tantalum ore in this study was classified as refractory mineral of low-grade which was mainly composed of fergusonite, polycrase, ilmenorutile, and bastnasite. Most of niobium and rare earth metals were dis- seminated in these minerals （particle sizes of 95 % rare earth elements 〈40 μm）, which cannot be concentrated through traditional floatation process and treated by the current hydrofluoric acid leaching in industry application. It is nec- essary to develop a new approach to recovery these valuable metals. In this study, an improved method is proposed to extract these metals, which includes acid roasting and sulfuric acid leaching. The influence of mineralogy, acid concentra- tion, leaching temperature, leaching time, and liquid to solid ratio was experimentally studied. It is observed that after the ground ore （-74 μm） was roasted at 350 ℃ for 2 h with sulfuric acid （18.4 mol.L- 1） in the ore to acid mass ratio of 1：1, and then the roasting residue reacted with 25 % sulfuric acid at 90 ℃ for 2 h, the recovery rate of rare earth elements reaches 〉90 %, and the leaching extent of niobium can reach 84 %.
文摘针对云南某细粒难选赤褐铁矿石含磷超标,须提铁降磷方能利用,但采用常规的强磁选、重选、浮选方法均无效果的情况,采用焙烧—浸出新工艺及自行研发的浸出剂,在焙烧温度为1 000℃、焙烧时间为15 m in、浸出剂浓度为10%、浸出液固比为3∶1、浸出时间为5 m in条件下,获得了精矿铁品位为66.43%、磷品位为0.131%、铁回收率为98.89%的理想指标,目前正开展工业试验。试验结果为难选铁矿资源的开发利用提供了新的思路。
