Effect of phosphogypsum on saline-alkalinity and aggregate stability of bauxite residue

A column experiment was conducted to investigate the effect of phosphogypsum (PG) on the saline- alkalinity, and aggregate stability of bauxite residue. Results showed that: with increasing leaching time, the concentrations of saline-alkali ions decreased while the concentration increased in bauxite residue leachate; compared with CK (control group) treatment, pH, electric conductivity (EC), exchangeable sodium percentage (ESP), sodium absorption ratio (SAR), and exchangeable Na⁺ content of bauxite residue were reduced following PG treatment; average particle sizes in aggregates following CK and PG treatments were determined to be 155 and 193 nm, respectively. SR-μCT test results also confirmed that bauxite residue following PG treatment acquired larger aggregates and larger pore diameter. These results indicate that the PG treatment could significantly modulate the saline-alkalinity, and simultaneously enhance aggregate stability of bauxite residue, which provides a facile approach to reclaim bauxite residue disposal areas.     

Reaction behavior of quartz in gibbsite-boehmite bauxite in Bayer digestion and its effect on caustic consumption and alumina recovery

A high content of quartz is usually present in Australian gibbsite-boehmite bauxite. The reaction between quartz and sodium aluminate solution at high temperatures in the Bayer process can lead to loss of alumina and sodium oxide. Therefore, to improve alumina recovery, the reaction of quartz needs to be avoided. The digestion behavior of Australian gibbsite-boehmite bauxite and pure quartz in the Bayer process at 230–250 °C was systematically studied in this paper. The mineral composition and morphology of the reaction products were characterized and the kinetics of the quartz dissolution process was studied in detail. It was shown that boehmite in gibbsite-boehmite bauxite can be completely digested at high temperature (250 °C) with a short digestion time (5 min). A short digestion time results in a low reaction rate of quartz in bauxite, and is ideal for alumina recovery at high temperatures. The quartz reaction rate rapidly increases with longer digestion times. The apparent activation energy of the dissolution of quartz in bauxite in the caustic solution is 151.9 kJ mol^?1, and the rate-controlling step of this reaction process is the interfacial chemical reaction. By controlling the particle size of bauxite, the digestion temperature, and the digestion time, the reaction rate of quartz in bauxite can be inhibited, which is beneficial for improving alumina recovery and reducing caustic consumption. Therefore, based on the above theoretical research, a process for digesting gibbsite-boehmite bauxite is proposed using high digestion temperature (250 °C), short digestion time (5 min) and large mineral size. An economic benefit of about US$101.9 million for a refinery with the annual output of 2 million tons of alumina can be created by the proposed process.     

贵州某高硫铝土矿反浮选脱硫试验

贵州某高硫铝土矿Al₂O₃含量为62.60%、硫含量为7.15%，铝硅比为11.54，矿石有用矿物主要为一水硬铝石，属于典型的高品位一水硬铝石型高硫铝土矿。为给该矿石合理开发利用流程确定提供依据，采用反浮选脱硫工艺进行试验。结果表明，在磨矿细度为-0.074 mm占85%条件下，以碳酸钠为矿浆pH调整剂，硫酸铜为活化剂，改性淀粉为抑制剂，丁基黄药为捕收剂，松醇油为起泡剂，经1粗1精2扫、精选尾矿和扫选精矿均返回至粗选闭路流程浮选试验，获得了氧化铝含量72.06%、含硫量0.27%的精矿产品，试验结果可以为该铝土矿的资源开发提供参考。     

贵州某高硫铝土矿浮选脱硫试验研究

对贵州某高硫铝土矿进行了浮选脱硫试验研究。结果表明, 在磨矿细度-0.074 mm粒级占82.64%, 碳酸钠用量1 800 g/t、硫酸铜用量150 g/t、丁黄药总用量600 g/t、2^#油总用量240 g/t条件下, 经一粗两精两扫闭路反浮选, 获得了硫含量0.26%的铝土矿精矿, 脱硫率达到85.86%。试验结果可为该类铝土矿资源的综合开发利用提供借鉴。     

低品位铝矾土在高铝质电瓷配方中的应用研究

对低品位铝矾土代替高铝质电瓷配方中的优质铝矾土进行了试验研究。结果表明,通过冷等静压干法生产工艺制备的试验样品,在合适的配比和烧成制度下,能够满足高铝质瓷绝缘子的性能要求。     

电解锰压滤渣高温脱硫研究

采用直接煅烧法、还原法及添加脱硫剂煅烧法对电解锰压滤渣进行了高温脱硫,研究了不同方法得到的脱硫产物的物相、残硫量和活性,并比较了几种方法的工业适用性。结果表明:直接煅烧法的脱硫渣和坩埚粘连严重,实际操作困难;加入煤粉并没有改善脱硫渣和坩埚的粘连问题,且脱硫渣中残硫量高;石灰石虽能减弱脱硫渣和坩埚的粘连,但由于生成惰性物质石英,降低了脱硫渣的活性;采用铝矾土作为脱硫剂进行脱硫,脱硫渣的残硫量低,脱硫渣和坩埚不粘连,脱硫渣活性高。铝矾土添加量为42%(质量分数),脱硫温度为1 250 ℃,脱硫保温时间为5 min时,脱硫渣中硫含量为0.089 4%(质量分数),达到脱硫要求。     

十二碳酰胺的合成及其浮选性能研究

本文研究以十二碳酸和尿素为原料,通过一系列反应最终合成得到十二碳酰胺。首先通过单因素试验考察温度、时间和物料比对反应转化率的影响,然后利用正交试验对反应条件进行优化。得到十二碳酰胺的最佳合成条件:物料比1∶1、温度170℃、时间4h,最高转化率88.52%。利用合成的产物作捕收剂对铝土矿试样进行分选,在不加抑制剂和分散剂的情况下,得出十二碳酰胺的适宜pH值为5,最佳用量为160g/t,氧化铝回收率可达到80.85%,具有良好的浮选性能。     

微细粒级浮选铝土矿尾矿颗粒聚集沉降行为研究

对影响微细粒级铝土矿尾矿颗粒聚集沉降行为的因素进行了试验分析。研究发现:无机凝聚剂和高分子有机絮凝剂复配使用,聚合氯化铝用量0.1 mol/L,分子质量1 800万的含羧基官能团(—COOH)有机絮凝剂分两次添加,每次用量15 g/t,初始搅拌强度500 r/min,搅拌强度梯度递减条件下,铝土矿尾矿颗粒的聚集沉降行为较为显著。     

矾土对Al_2O_3-SiO_2质可塑料性能影响

以4种不同Al2O3含量的矾土及SiO2微粉和Al2O3微粉为原料,以Al(H2PO4)3/H3PO4和铝酸钙水泥为结合剂和促凝剂,通过混炼、成型、养护、烘干等工序制备了Al2O3-SiO2质可塑料。通过引入不同品位矾土原料,重点研究不同Al2O3含量的矾土原料对烘干后及1100℃烧后可塑料体积密度、常温强度、烧后线变化率、耐磨性、矿物相组成及基质微观结构的影响。结果表明,随着矾土Al2O3含量增大(即提高矾土品位),烘干后和烧后Al2O3-SiO2质可塑料体积密度逐渐增大,常温强度减小。随着原料矾土品位提高,可塑料烧后矿物组成中刚玉相特征峰强度会逐渐增强,矾土中杂质及铝酸钙水泥对可塑料起助烧结作用。矾土中Al2O3含量增大,会增大骨料颗粒强度,但会降低基质烧结性,最终导致基质与骨料强度匹配性变弱,烧后可塑料磨损量增大,耐磨性降低。     

矾土尾矿载体氧化物组分对甲苯催化燃烧的影响

利用固体废弃物矾土矿尾矿制备催化剂载体,采用浸渍法将氧化物活性组分载于催化剂载体,对甲苯催化燃烧进行了研究。实验结果表明:以矾土矿尾矿制备的催化剂载体,所选4种单一活性组分中,催化效果较好的为Mn/Zr O2和Cu/Zr O2整体催化剂,其负载14%Mn/Zr O2整体催化剂在260℃时转化率为47%,负载16%Cu/Zr O2整体催化剂在300℃时转化率为49%,均接近起燃温度。