Investigation of the effect of mineralogy as rate-limiting factors in large particle leaching

Although heap leaching is by now well established in the mining industry, the process remains limited by low recoveries with different rate-limiting factors that are not clearly understood. In this study, three large particle size classes (+19/−25, +9.5/−16, +4.75/−5 mm) were prepared from a sphalerite ore by two different methods of comminution (HPGR and cone crusher). The particles were then packed into leach reactors that were operated continuously for 11 months with well-mixed internal circulation of the leach solution. Characterization of the residue of the leach reactors indicated that there are areas within the ore particles where although sphalerite grains are accessible to the solution, they remain unreacted. X-ray tomography and QEMSCAN® analysis of the selected samples before, during and after leaching, showed increased leaching of sphalerite grains associated with pyrite due to galvanic interactions. Mineral chemistry (Fe, Mn content of sphalerite) and jarosite precipitation were also investigated as factors influencing sphalerite leaching.     

Processing of ZrO2 scaffolds coated by glass–ceramic derived from 45S5 bioglass

Three dimensional, highly porous, ZrO₂ scaffolds coated by glass–ceramic derived from 45S5 bioglass were fabricated. The surface reactivity of 45S5 in aqueous solution was investigated as a function of the immersion time. The influence of the solid loading on the rheological behavior of 45S5 aqueous slips with ammonium polyacrylate (NH₄PA) was studied; besides the effect of poly(vinyl)alcohol (PVA) on the relative viscosity was determined. The structure and microstructure of uncoated and coated ZrO₂ scaffolds were characterized. The high ionic exchange capability of 45S5 was demonstrated by the pH rise, the significant weight loss and the amorphous calcium phosphate nucleation, upon its immersion in aqueous solution. The addition of PVA did not affect the dispersion properties of the 45S5 powder, which were basically controlled by its negative surface charge. 30 wt% 45S5 slips with 4 wt% PVA exhibited a yield stress and an adequate viscosity in the low shear rate range, to produce a bioglass coating into the ZrO₂ scaffold. The glass-ceramic coating was distributed along the strut surfaces, forming a thin film without altering the porosity and the strut thickness of the original ZrO₂ scaffold structure.     

Boosting the antimicrobial and Azo dye mineralization activities of ZnO ceramics by enhancing the light-harvesting and charge transport properties

Herein, we report the wet-chemical synthesis of a ferromagnetic nickel-doped ZnO (Zn_1-xNi_xO) nanocatalyst as a novel and visible-light-driven photocatalyst. Through X-ray diffraction, UV/Vis absorption, electronic studies, and current-voltage experiments, the effect of the ferromagnetic nickel dopant on the structural, optical, morphological, and electrical properties of the synthesized Zn_1-xNi_xO nanocatalyst was studied. The Ni-doping introduced the structural variation in the Zn_1-xNi_xO nanocatalyst, exhibiting a visible light-triggered optical band gap of 2.96 eV and an excellent current conductivity of 6.3 × 10⁻⁴ Sm⁻¹. Moreover, the synthesis of the Zn_1-xNi_xO catalyst at the nanoscale enhanced its surface energy, showing a robust affinity to stick with the dye and pathogenic microbes. The synergistic effects of all the mentioned features enable our Zn_1-xNi_xO nanocatalyst to efficiently generate and transport reactive oxygen species (ROS) under visible light illumination. Regarding antibacterial action, the as-synthesized Zn_1-xNi_xO nanocatalyst showed 1.7% higher activity against E. coli than that of the drug Ciprofloxacin. In addition, doped nanocatalysts mineralize almost 97% of the Allura red dye in just 80 min with a constant rate value of 0.036 min⁻¹. The impedance study and post-application XRD proposed that our Zn_1-xNi_xO nanocatalyst has good conductivity and structural stability. Applications studies show the unusual photocatalytic activity of as-synthesized Zn_1-xNi_xO nanocatalysts, which makes it a suitable candidate for industrial discharge treatment applications at the expense of solar light.     

车河选矿厂锌硫分离尾矿综合回收工艺改进试验研究

针对车河选矿厂锌硫分离尾矿综合回收工艺存在的金属回收率低、精矿中各种金属互含高且有害杂质含量高等问题,开展了多级沉降工艺研究、磁选工艺研究、阶段浮选工艺研究等一系列研究,并在生产中得到应用,最终硫精矿品位及回收率分别提高1.87%、2.65%,硫精矿含砷由1.82%降低至1.2%;中度锡精矿品位及回收率分别提高1.25%、0.58%,中度锡精矿含铁由28.79%降低至25.68%,经济效益显著。     

从黑山铁矿中回收钛铁矿的试验研究

为了提高选铁尾矿中钛铁矿的分选指标,对强磁选的钛铁矿粗精矿进行了浮选试验研究。粗精矿含有的主要脉石矿物为黄铁矿、斜长石等,其中TiO2含量为27.40%,试样经脱硫后采用EM351-2与EM351-3混合药剂作为捕收剂时,经过一次粗选,五次精选,可得到品位47.23%,回收率58.29%的钛精矿,并且质量浓度在26~32%范围内试验室指标稳定。现场连续运转26班次后,可得到TiO2平均品位46.51%,平均作业回收率62.37%的稳定指标。     

某铜钼矿高效选矿新技术研究

根据某复杂铜钼矿石的原矿性质,进行了选矿试验研究。采用硫化钠及硫酸铵活化铜钼矿物,碳酸钠调整矿浆pH值,用煤油捕收铜钼矿物,可以实现铜钼矿物的高效浮选回收。在铜钼混浮粗选条件试验及精选抑制剂种类和用量试验的基础上进行了实验室小型闭路试验,可获得铜钼精矿,铜品位及回收率分别为24.41%和85.92%,钼品位及回收率分别为0.52%和70.73%。     

某复杂共生铜铅银多金属硫化矿的选矿工艺研究

某铜铅银多金属硫化矿,主要目的矿物方铅矿、黄铜矿与黄铁矿之间嵌布关系紧密复杂,黄铜矿嵌布粒度微细,严重干扰浮选指标。研究采用铜铅混合浮选再分离工艺对原矿中的有价元素进行了综合回收。获得了Cu品位20.52%、Cu回收率65.11%的铜精矿,Pb品位58.91%、Pb回收率90.01%的铅精矿,同时综合回收了贵金属银,有效地提高了资源综合回收率,研究所采用的工艺与药剂制度对微细粒嵌布硫化矿的选矿具有指导意义。     

白马选矿厂一期破碎除尘系统优化改造方案

通过分析白马选矿厂一期破碎除尘系统现状、存在问题和介绍干雾抑尘技术在密地选矿厂破碎除尘优化改造的应用经验,从而提出采用干雾抑尘技术和布袋除尘器对一期破碎除尘系统进行优化改造的方案,以达到节能减排的目的 .     

一段磨矿与两段磨矿的对比研究

通过技术指标对比,分析了一段磨矿流程与两段磨矿流程相比铜回收率指标偏低的主要原因。两段磨矿产品粒级组成优于一段磨矿的,因此可以得到更好的选矿指标。     

攀西地区钒钛磁铁矿石弱磁选工序前浮选硫钴的探讨

攀西地区是我国最大的钒钛磁铁矿产区,钒钛磁铁矿石中除了主要元素铁、钒、钛以外,还伴生有硫资源储量6 000万t、钴资源储量90万t,具有很高的工业利用价值。当前攀钢矿业公司选矿厂对钒钛磁铁矿的选矿工艺流程是“阶段磨矿—弱磁选铁—选铁尾矿强磁选钛—强磁选钛粗精矿浮选脱硫—浮选钛铁矿”得到铁精矿、钛精矿和硫（钴）精矿,仅在钛精矿浮选脱硫阶段浮选回收得到硫（钴）精矿,因为钴品位＜0.3%,钴市场价格高时作为硫钴精矿销售,钴市场价格低时只能作为硫精矿销售,造成了钴资源的浪费。开展了弱磁选工序前浮选回收硫钴的试验研究,目标是硫化矿物的早收快收集中收。实验室在磨矿细度-0.074 mm占45%,硫酸铜用量250 g/t、异戊黄药用量150 g/t、3#起泡剂用量30 g/t,一段浮选得到产率14.33%,硫品位3.11%、钴品位0.06%、镍品位0.03%、铜品位0.10%,硫回收率68.14%、钴回收率35.12%、镍回收率47.23%、铜回收率43.12%的粗硫钴精矿。探讨了实验室球磨机磨矿浮选一体机和浅槽快速浮选机,并开展了验证试验,认为浅槽快速浮选机是研究发展方向。