湿法炼锌二次置换后液脱除铊的实验研究

针对工业上硫酸锌溶液二次置换后液中铊的分布特征,采用锌粉置换、锌粉+活性炭、锌粉+高锰酸钾、锌粉+乙酸铅等方法脱除二次置换后液中的铊。结果表明,反应温度70℃、高锰酸钾用量3g、锌粉加入量40g、搅拌转速300r/min、反应时间90 min的条件下,锌粉+高锰酸钾联合法可以脱除85.83%的铊。在反应温度90℃、乙酸铅用量0.8g、锌粉加入量40g、搅拌转速300r/min、反应时间90min的条件下,锌粉+乙酸铅联合法可以脱除93.89%的铊。结合工业生产实际,建议采用锌粉+乙酸铅联合法脱除二次置换后液中的铊。     

湿法炼锌二次置换后液脱除铊的研究

针对工业上硫酸锌溶液二次置换后液中铊的分布特征,采用锌粉置换、锌粉+活性炭、锌粉+高锰酸钾、锌粉+乙酸铅等方法脱除二次置换后液中的铊。结果表明,反应温度70℃、高锰酸钾用量3g、锌粉加入量40g、搅拌转速300r/min、反应时间90 min的条件下,锌粉+高锰酸钾联合法可以脱除85.83%的铊。在反应温度90℃、乙酸铅用量0.8g、锌粉加入量40g、搅拌转速300r/min、反应时间90min的条件下,锌粉+乙酸铅联合法可以脱除93.89%的铊。结合工业生产实际,建议采用锌粉+乙酸铅联合法脱除二次置换后液中的铊。     

从酸性硫脲浸金溶液中回收金的方法

介绍了酸性硫脲浸金的原理及从硫脲浸金液中回收金的主要方法,包括活性炭吸附法、离子交换树脂吸附法、溶剂萃取法、置换沉淀法、加氢不法。评述了各种方法的应用情况及其各自的优缺点,并对未来进行了展望。     

用铁粉从酸性淋洗液中置换金银铜试验研究

研究了用铁粉从某黄金冶炼渣氯化焙砂淋洗液中置换回收金、银、铜,考察了铁粉用量、置换时间、温度对金、银、铜置换率的影响。结果表明:在铁粉用量9g/L、反应时间50min、温度60℃条件下,溶液中金、银、铜置换率分别达98.51%、98.85%和96.51%,置换回收效果较好。     

硫脲法浸金的工艺优化试验

介绍了在酸性溶液中硫脲浸金的主要影响因素,提出氧化焙烧-预浸处理-硫脲浸金的工艺优化思路,并经过试验得出最佳工艺参数为:FeCl_3用量为0.5%,硫脲用量为2.5%,pH=1.0,浸出温度25℃,反应时间10 h,液固比2.5:1,在此条件下金浸出率为84.76%。     

SLS—H2SO4体系中铝粉置换回收硫脲金的研究

研究了在阴离子表面活性剂十二烷基硫酸钠（ＳＬＳ）存在下从硫酸硫脲金溶液中用铝粉置换金的条件。结果表明，由于ＳＬＳ的分散、浸润作用，金的置换率显著提高，可满足低含量硫脲浸金液的深度置换回收要求。     

生物炭还原五价钒的行为研究

针对钒化合物随价态升高毒性增加,且其对环境造成的危害也增大的现状,研究采用生物炭对其进行还原实现无害化处置。试验研究了生物炭用量、反应温度、硫酸浓度、反应时间等反应参数对钒还原率的影响。结果表明:五价钒在酸性条件下主要以VO_2~+、H_3V_(10)O_(28)~(3-)和H_2VO_4~-的形式存在,在短时间内可以被生物炭还原成低价。在合适的反应条件下,即:钒的初始浓度为3 g/L,生物炭用量为3 g,反应温度为90℃,反应时间为60 min,硫酸浓度为20 g/L和搅拌转速为500 r/min,钒的还原率可达92.14%。在生物炭将五价钒还原的过程中不会引入其他杂质,该方法进行技术改良后在实现五价钒无害化的同时还可以用来制备低价钒化合物。     

某尾渣硫脲浸出金试验研究

对某尾渣,在比较了硫脲、硫氰酸铵、硫代硫酸钠浸金效果的基础上,选择硫脲为浸出刺。试验通过优化浸出条件,确定硫脲质量浓度为15g／L、硫酸用量为55mL、液固比为3、搅拌浸出3h,金的硫脲浸出率可达到93．50％。试验还考察了硫脲溶液循环使用效果,可在一定程度上降低浸金过程中硫脲的消耗。     

置换法从废定影液中回收银的研究

研究了用金属铁作置换剂从洗相废定影液中回收银的工艺及其影响因素;确定了最佳置换条件为:铁粉用量3.8 g/L,pH值 5.5,温度40 ℃,搅拌速度1 440 r/min,搅拌时间30 min.在该试验条件下,银的置换率达到95.6 %,回收1 kg银的成本为58.6元.     

以含铜废液为原料制备铜铁复合粉的工艺研究

采用酸性和碱性铜盐废液中和,有机酸作为添加剂,用还原铁粉置换含铜废液中铜,制备了含铜量为20%的铜包覆铁的复合粉.采用火焰原子吸收光谱法、惰气脉冲红外热导法、扫描电子显微镜和X射线衍射对粉末的成分、形貌进行了研究,分析了铜离子浓度、反应时间、干燥还原条件对复合粉特性的影响;并对粉末进行了真空热压试验.实验结果表明:铜铁复合粉为包覆型结构,Cu层厚度约为1μm;溶液中铜离子浓度愈高,反应速率愈快,反应时间在25～30 min范围内;较合适的干燥还原条件应为:温度在500～650℃之间,时间2～3 h.粉末由Cu和Fe两相构成,没有其他杂质相.≤74 μm较≤μm150μm的粉末的烧结试样的HRB硬度和抗弯强度在相应的温度下高,真空热压性能比较稳定的温度区间是700～750℃.     

三氯化铁浸出-重铬酸钾滴定法测定钛精粉还原产物中的金属铁

试样用三氯化铁溶液溶解,金属铁被氧化为二氯化铁,过滤分离,滤液酸化后以二苯铵磺酸钠为指示剂,用重铬酸钾标准溶液滴定,实现了钛精粉还原产物中金属铁含量的测定。结果表明,试样粒度在0.125 mm以下时,FeCl3溶液浓度和用量分别为10 g/L和100 mL,采用电磁搅拌60 min为最佳的实验条件。分别用HgCl2分析法、矿相法对方法正确度进行检测,其中F检验和t检验判定此法与HgCl2法无显著性差异,同时,浸出前后试样的X射线衍射图谱对照和金相照片对比进一步证明滤渣中没有金属铁相,铁浸出完全。方法用于测定钛精粉还原产物样品,结果的相对标准偏差小于2%。     

铁粉预还原—硫化亚铁脱除高酸性硫酸铁溶液中的砷

焙烧氰化法提金尾渣经酸浸后产出大量酸性硫酸铁溶液,因其中含有较高的砷而限制了其高值化利用。采用铁粉预还原—硫化亚铁脱砷对溶液中的砷进行脱除研究。结果表明,溶液中砷的存在形式及分布与溶液体系电位密切相关,铁粉可以有效降低溶液电位,经铁粉预还原后硫酸铁溶液中的砷可用硫化亚铁有效脱除。当铁粉添加量为溶液中铁含量的0.6倍,溶液加入36.6g/L的FeS,搅拌30min,可使溶液中砷含量由0.253g/L降低至4.79mg/L。空气对脱砷过程有不利影响。     

Hydrogen reduction of copper bleed solution from an Indian copper smelter for producing high purity copper powders

A bench scale investigation on the hydrogen reduction of a highly acidic copper bleed solution to produce high purity copper powder is discussed in this paper. A titanium lined autoclave of 1 L capacity was used for this study. The parameters optimized on the bench scale were validated by performing hydrogen reduction of copper in a larger autoclave. Effect of various parameters viz., time of reduction, temperature of reduction, pressure variation, iron dose, volume of copper solution etc. were studied. Experiments were performed with synthetic and actual solution obtained from a copper plant. A 99% copper powder recovery is achieved by hydrogen reduction at a pressure of about 2400 kPa, reaction temperature of 453 K, stirring speed of 400 rpm for a reaction time of 2 h. The fine copper powder thus obtained had a good metallic lustre. Kinetics of reduction of copper was examined by drawing samples at different times and analyzing the percent copper reduction. The copper depleted solution was further purified with respect to the residual copper and can be processed for the recovery of nickel powder by hydrogen reduction.Properties of the copper powder obtained from the large-scale experiments from actual plant and synthetic solutions have been evaluated for powder metallurgical applications. The raw and annealed copper powders obtained from the synthetic copper solution were found to have an apparent density of 3.50 g/cm³, flow rate 35.6 g/min, hydrogen loss 0.2%, purity 99.8% and green density of 8.6 g/ cm³ while the powder from actual plant solution was found to have an apparent density of 3.59 g/ cm³, flow rate 46.0 g/min, hydrogen loss 0.6%, purity 99.4% and green density 8.6 g/ cm³. Thus, the copper powder produced by hydrogen reduction was found suitable for the application.     

硫铁矿还原烧渣酸浸液试验研究

研究了硫铁矿精矿还原硫酸烧渣酸浸液及其反应机理。试验结果表明:当浸出液中Fe3+浓度为1.1 mol/L时,在液固比为3∶2、90℃、搅拌速度500 r/min的条件下,反应3 h,酸浸液中的Fe3+的还原率达到96.5%,其反应级数为1.66,表观活化能为60.26 kJ/mol。     

PFS法处理镍钼矿酸浸液萃钼余液的研究

采用聚合硫酸铁(PFS)法处理镍钼矿酸浸液萃钼余液中的重金属离子和化学耗氧量(COD),考察双氧水用量、PFS用量、搅拌时间、pH对余液中Zn~(2+)、Pb~(2+)、Ni~(2+)及COD含量的影响。结果表明,在双氧水用量20 mL/L、PFS用量60 mg/L、搅拌时间90 min、pH 11.0的条件下,COD可降至500 mg/L以下,去除率高达89%,重金属离子均达到GB 8978-1996污水综合排放一级标准。     

Substitution Recovery of Gold from Copper-Ethylenediamine-Thiosulfate Leaching Solution with Copper Power

The substitution method of recovering gold from thiosulfate-ethylenediamine (en)-Cu²⁺ leaching solution using copper powder was studied. The effects of reaction time, stirring speed, pH, thiosulfate concentration, en/Cu²⁺ molar ratio, Cu/Au⁺ mass ratio, and temperature on gold recovery were systematically examined. The experimental results showed that reaction time, stirring speed, thiosulfate concentration, en/Cu²⁺ molar ratio, Cu/Au⁺ mass ratio, and temperature have a significant influence on the recovery rate of gold, whereas the pH has little effect. A high gold recovery rate of 95.38% was achieved in 0.2 mol/L thiosulfate at 40°C after 40 min with a stirring speed of 400 rpm, pH of 11, en/Cu²⁺ molar ratio of 6, and Cu/Au⁺ mass ratio of 150. A kinetic study revealed that the reduction of gold-thiosulfate complex ions (Au(S₂O₃) ₂ ^3- ) on the surface of copper powder follows a first-order kinetics model with an apparent activation energy of 39.82 kJ/mol.     

Kinetics of hexavalent chromium reduction by grey cast iron powder

The kinetics of Cr (VI) reduction by grey cast iron powder (HT250 as per Chinese standard GBT 9439-2010) was investigated in this paper. Factors such as pH, initial Cr (VI) concentration, particle size, stirring speed and temperature on Cr (VI) reduction were first examined at a moderate reducing agent dosage. It was found that Cr (VI) reduction could only occur at an initial pH of 2.0 and above this value, the reaction nearly stopped. Additionally, the obvious dependence of Cr (VI) reducibility on other parameters was also revealed. The changes of pH, ORP and the concentration of Fe ions during the reaction were investigated. The correlations between the experimental data and reaction models involving homogeneous and heterogeneous reactions were studied. The results indicated first-order kinetics for the Cr (VI) reduction, which was a homogeneous reaction with an apparent activation energy of 20.718 kJ/mol. A semi-empirical equation was proposed to describe the kinetics of Cr (VI) reduction by HT250 powder. It was concluded that HT250 powder was a promising zero-valency iron (ZVI) material offering excellent reducibility and its use can be extended to the pre-treatment of wastewater containing other heavy metal ions such as Cu(II) and Pb(II).     

核桃壳还原浸出软锰矿的动力学

探究以核桃壳为还原剂硫酸浸出氧化锰矿过程的动力学。考察了搅拌速度、反应温度、硫酸浓度、反应时间以及核桃壳用量对锰浸出率的影响。结果表明,锰的浸出率随着搅拌速度、硫酸浓度、核桃壳用量的增大和温度的升高而增大。浸出前60 min浸出率的增长速度较快。在反应温度为369 K、硫酸浓度3.5 mol/L、核桃壳加入量40 g/L、反应时间2.5 h、转速200 r/min时,锰浸出率达93.18%。浸出过程属于化学反应控制,对应的活化能为45.5 kJ/mol,硫酸浓度和核桃壳用量的反应级数分别为0.897、0.2。     

高铁铝土矿直接还原-溶出工艺

提出了一种以Na₂CO₃为添加剂、以煤为还原剂的还原分离方法,将原矿中铁的氧化物还原为铁单质粉末通过磁选分离回收,将水铝石矿物转化为铝酸钠溶出分离回收.通过单因素实验考察了还原温度、还原时间、Na₂CO₃用量和还原剂用量对粉末铁品位、铁回收率和氧化铝溶出率的影响,并用X射线衍射分析、扫描电镜观察和能谱分析等方法研究了反应的过程和机理.通过正交试验优化了实验参数,获得的最优条件为还原温度1150℃,还原时间45 min,Na₂CO₃用量40.47%,还原剂用量11.9%;在最优条件下,粉末铁品位为95.88%,铁回收率为89.92%,氧化铝溶出率为75.92%.