控制电位还原法回收氯化浸出液中的贵金属

以亚硫酸钠为还原剂,研究采用控制电位还原法回收氯化浸出液中的贵金属。结果表明:当控制金还原电位为530~550mV时,氯化浸出液中98%以上的Au将被还原沉淀至粗金粉中,同时Pt、Pd和Te基本不被还原沉淀,所得粗金粉中Au含量在98%以上,Se、Te、Cu和Pb等杂质的含量均低于0.10%(质量分数),而且该金还原电位对不同Au浓度或酸度的氯化浸出液都具有良好的适应性;然后当控制铂钯还原电位为390~420mV时,金还原后液中的Au、Pt和Pd将被还原沉淀至1mg/L以下,而Te基本不被还原,所得铂钯精矿中贵金属含量高、杂质含量少,且所确定的铂钯还原电位对不同铂钯浓度或酸度的金还原后液以及反应温度均具备较好的适应性。可见,通过控制电位还原,可将氯化浸出液中贵金属选择性沉淀并与其他元素初步分离。

锑矿氯化浸出液中Fe（Ⅱ），Sb（Ⅲ）和Sb（Ⅴ）的测定

本文报道在辉锑矿氯化浸出液中，不同价态离子共存时测定Ｆｅ（Ⅱ），Ｓｂ（Ⅲ）和Ｓｂ（Ⅴ）的分析方法。即先将一份试液在稀硫酸介质中测Ｆｅ（Ⅱ），再转为盐酸介质测Ｓｂ（Ⅲ）；另一份试液在ｐＨ１．０～１．５使锑离子水解与干扰离子分离，测定总锑量，用差减法求出Ｓｂ（Ⅴ）含量。测定都采用硫酸铈标准溶液滴定。本法应用于锑矿氯化浸出液中Ｆｅ（Ⅱ），Ｓｂ（Ⅲ）和Ｓｂ（Ⅴ）的分析，具有干扰少，准确，简便的优点。

锑矿氯化浸出液中锑的价态分析

报导不同价态离子共存时测定Ｓｂ３＋和Ｓｂ５＋的方法。先将一份试液在稀硫酸介质中测Ｆｅ２＋，转为盐酸介质测Ｓｂ３＋；另一份试液在ｐＨ１．０～１．５使锑离子水解与干扰离子分离，测定ＳｂＴ量，差减法求出Ｓｂ５＋量。锑的测定采用硫酸铈盐法。

铅阳极泥氯化浸出液除氟研究

选用氯化钠脱除铅阳极泥氯化浸出液中的氟硅酸和氟硅酸盐,考察了氯化钠加入量、反应时间、沉降时间、温度等对氟脱除率的影响。在最佳工艺条件下,浸出液中氟浓度可降至2.43g/L以下,除氟率达87.7%。除氟后溶液在蒸馏过程中不产生结晶物,避免蒸馏管道发生堵塞现象,馏出液中氟浓度均在3g/L以下,可以作为稀酸返回浸出。

氯化浸出液的研究

配比为15%FeCl_3+15%NaCl+1.5%CuCl_2+1.5%HCl的氯化浸出液可除去Pb>96%、Cu>94%,使含Mo 55%、Pb 2%、Cu1%的浮选精矿质量提高为含Mo56.6%、Pb<0.04%、Cu<0.07%,成本较低.

铅银渣氯化浸出液净化及有价金属回收试验

采用净液-置换工艺处理铅银渣氯化浸出液并提取银、铅,重点研究了铅粉置换银、铁粉置换铅的工艺影响条件。结果表明:利用Fe3+易水解的特性,采用中和除铁,石灰调节溶液pH为4.0即可完全除铁,铅粉加入量为6 g/L,pH=1.5~2.5,温度60 ℃,置换时间40~60 min,在此条件下,银的置换率大于98%,溶液中残银浓度低于1 mg/L;两段逆流可以较完全置换出溶液中的铅,两段综合置换率为87.08%,最终置换产物含铅量>90%,满足精炼要求。

从氯化浸出液中选择性分离锡

用ＴＢＰ作萃取剂研究了从含Ａｇ，Ｃｕ，Ｓｂ，Ａｓ，Ｓｎ，Ｆｅ，Ｐｂ的氯化浸出液中萃取Ｓｎ。分离Ｓｎ的最佳萃取条件为：２５％ＴＢＰ－１０％１－ 醇－６５％煤油（体积％）。用ＨＣｌ作反萃取剂，采用四步反萃，达到〉８０％的Ｓｎ回收率。

乳状液膜浓缩稀土(Ⅰ)(英文)

研究了用乳状液膜从ＮａＣｌ型浸出液中浓缩稀土的工艺因素。这些因素包括油内比（Ｒｏｉ）、膜相中煤油／石蜡比、表面活性剂用量、内相酸度、料液中稀土浓度、水乳比（Ｒｗｅ）、流动载体Ｐ５０７和Ｐ２０４的比较以及搅拌时间。通过实验获得了一个适宜的液膜组成（Ｎ２０５Ｐ５０７煤油液体石蜡ＨＣｌ）和一些较佳的操作条件。液膜富集稀土的浓度可达１００ｇ·Ｌ－１，稀土提取率可达９６％。

Enhanced extraction of scandium and inhibiting of iron from acid leaching solution of red mud by D2EHPA and sodium chloride

D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl concentration(C_(NaCl)),pH value,reaction time,stirring speed and O/A were investigated to extract scandium and separate iron from the acid leaching solution.The extraction mechanism was analyzed by Fourier transform infrared spectroscopy(FT-IR)and thermodynamic theory.The single-stage extraction efficiency of scandium,iron andβ(Sc/Fe)were 99.1%,9.4%and 1061.2,respectively,with C_(NaCl) of 75 g/L and XP204 of 0.75 at solution pH value of 1.2 and stirring speed of 200 r/min for 6 min,in which a good separation effect of scandium and iron was obtained.The vibration absorption peak Sc─O was contributed to the extraction of scandium with P204.The complex[FeCln]^(3−n) existed in the solution with adding NaCl into the acid leaching solution.The value of n was higher and the valence state of the complex[FeCln]^(3−n) was lower with an increase of chloride concentration,which restricts the extraction efficiency of iron with P204.The extraction of three stages in the counter-current simulation experiments was carried out according to the McCabe-Thiele diagram.Gibbs free energy change(ΔG)of−5.93 kJ/mol,enthalpy change(ΔH)of 23.45 kJ/mol and entropy change(ΔH)of 98.54 J/(mol·K)were obtained in the solvent extraction proces,which indicate that the extraction reaction is easily spontaneous and endothermic and a proper increase of temperature is conducive to the extraction of scandium.

Effects of Surfactant on Zinc Recovery by Solvent Extraction during Leaching in HCl-FeCl_3 Solution

The effects of surfactant on the solvent extraction in leachingsphalerite were investigated. It is found that sodium dodecylsulfonate is the effective surfactant in improving the zinc recoveryfrom sphalerite in the aqueous FeCl_3-HCl-tetrachloroethylene system.Through the measurements of surface tension and viscosity of thesphalerite Slurry modified with different surfactants, it isconcluded that sodium dodecyl sulfonate in the concentration rang Of0.05 to 0.2 g·L^-1 can improve the viscosity of sphalerite slurry inthe water, decrease the surface tension of Leaching solution, preventthe aggregation of ore particles, and give very high zinc extraction.

Dissolution kinetics of low grade complex copper ore in ammonia-ammonium chloride solution

The leaching kinetics of Tang-dan refractory low grade complex copper ore was investigated in ammonia-ammonium chloride solution.The concentration of ammonia and ammonium chloride,the ore particle size,the solid-to-liquid ratio and the temperature were chosen as parameters in the experiments.The results show that temperature,concentration of ammonia and ammonium chloride have favorable influence on the leaching rate of copper oxide ores.But,leaching rate decreases with increasing particle size and solid-to-liquid ratio.The leaching process is controlled by the diffusion of the lixiviant and the activation energy is determined to be 23.279 kJ/mol.An equation was also proposed to describe the leaching kinetics.