Extracting metals from ammoniacal solution with low rank coals

Metals which form soluble stable ammine complex cations were extracted by lignite and brown coal by adsorption from ammoniacal solutions of the metal sulfates and carbonates. Known dry weights of the coal were contacted with the solution by agitation in closed polyethylene containers and then separated by filtration. The amount of metals adsorbed was determined from analysis of the solutions before and after contacting. It was found that metal loadings increase with increases in contact time, liquid to solid ratio and with metal concentration at short contact times, but loadings decrease with increases in coal particle size, ammonium ion concentration and with metal concentration at long contact times. Loading is affected only slightly by temperature and excess ammonia. In single contacting high loading is associated with low percentage extraction, and vice-versa, but relatively high values for both loading and extraction were obtained by counter-current contacting. The highest loadings obtained with single contacts, by using favorable combinations of conditions, were 22 pct copper, 15 pct nickel, 17 pct zinc, 31 pct cadmium, 37 pct silver and 13 pct cobalt. Comparative experiments were done with coals from Australia, United States of America, and West Germany. More development of the method is required before meaningful comparison could be made with other hydrometallurgical methods. It is speculated that possible applications could include treatment of ammoniacal solutions derived from sulfide, carbonate and oxide ores, pressure leaching of sulfides, preferential leaching of scrap metal,in situ solution mining and processing of oceanfloor nodules, arid effluent solutions which already contain ammonia.     

Extracting iron from aluminum sulfate solution

A solvent extraction process using Primene JMT (Rohm & Haas Company) as the extractant was investigated in this study in order to remove iron(III) (3–4 g/L) from an aluminum sulfate solution. The iron-loaded amine solution was regenerated by first stripping with 3.0 M NaOH solution, followed by neutralization with 1.5 M H₂SO₄ solution. To improved its extractability of iron, the amine solution was contacted again with a weak NaOH (0.275 M solution to adjust its pH value to between 6 and 7. A subsequent continuous experiment showed that the iron(III) concentration in the acid solution can be decreased from 3.18 to 0.0124 g/L, i.e. a 99.6% reduction, in a four stage counter-current extraction operation using the proposed regeneration procedure.     

Extracting noble metals from industrial solutions and waste waters with biosorbents

The chemical composition of various industrial solutions of the Shchelkovo Plant of Secondary Noble Metals is evaluated. It is established that the excess content of heavy metals with respect to gold and silver is larger by a factor of more than 1000. The microbial biomasses of various systematic groups are approved for extracting Au and Ag from solutions with a high salt background. The appropriateness of selectively extracting heavy metals from such complex solutions is shown. The behavior of heavy metals is investigated for sorption on biosorbents from individual solutions within the pH limits of 1.0–6.0 for the medium. The decisive significance of the pH of the solution (within the limits 1.0–3.0) on selectively extracting Ag from industrial solutions is determined. The notion that silver and heavy metals are attributed to different groups of metals by varying the degree of sorption with microorganisms, depending on the pH medium, is confirmed. The specific behavior of the biomass cells in the acidic medium also promotes the separation of these elements. Testing the biosorbed extraction of silver from the industrial solution on a granulated lincomycin biomass is approved under industrial conditions. The average degree of extraction was Cu ≤ 8.1, Ni 4.2, Zn 4.0, Fe 15.5%. The losses of biosorbent are about 70 g/m³ of the solution.     

采用Kaldo炉从阳极泥中提取稀贵金属

介绍了Kaldo炉的结构以及采用Kaldo炉从阳极泥中提取稀贵金属的工艺过程。     

Cobalt extraction in ammoniacal solution: Electrochemical effect of metallic iron

The dissolution behavior of iron and cobalt in ammoniacal ammonium carbonate solution has been investigated with the aid of Eh-pH diagrams for the Fe-NH₃-H₂O-CO₃ and Co-NH₃-H₂O-CO₃ systems, and electrochemical techniques such as open circuit potential measurements and potentiostatic and potentiodynamic polarization experiments. The polarization measurements indicate that both Fe and Co electrodes show active and passive behavior, and that Co dissolves at a more oxidizing potential than does Fe(e.g., E = ?0.34 V (SHE) for Co andE = ?0.52 V for Fe at a dissolution rate of 1 mA cm^?2). The active and passive current densities for Co are both greater than for Fe. In sintered Fe-Co mixtures, the presence of Fe shifts the potential of the maximum current to less noble values and also lowers the magnitude of this current. In addition there is practically no cobalt dissolution when the potential exceeds 0.6 V (SHE). It is suggested that the well-known poor recovery of cobalt from reductive-roasted ferruginous oxide ores may be partly related to the dissolution behavior of a metallic alloy phase containing both iron and cobalt.     

TXIB对Mextral973H从铜氨溶液中萃取铜及氨的影响研究

以Cu-NH_3-NH_4Cl-H_2O体系为研究对象,TXIB(2,2,4-三甲基-1,3-戊二醇双异丁酸酯)为改质剂,考察TXIB用量、萃取剂浓度、萃取相比、水相铜浓度、氨浓度等对萃取剂Mextral973H从铜氨溶液中萃取铜及氨的影响。结果表明,TXIB的使用可以显著降低氨的共萃而不影响铜的萃取。在萃取相比O/A=1/1、有机相浓度20%、铜浓度18.0g/L、氨浓度84.0g/L的条件下,向有机相中添加10%的TXIB后,铜萃取率由60.44%变化为60.20%,有机相共萃氨量从410.2mg/L降至154.8mg/L。     

Dissolution kinetics of zinc silicate (hemimorphite) in ammoniacal solution

The influence of ammonia-ammonium ratio, specific surface area of particles, associated anions, temperature and total ammonia concentration on the dissolution kinetics of zinc silicate (hemimorphite) has been investigated in ammoniacal solutions. The results show that the initial dissolution rate increases with the specific surface area, temperature and total ammonia concentration. The associated anions have a significant influence on the zinc extraction from hemimorphite due to their different complexing affinity with zinc ion. SEM analysis shows that cleavage of hemimorphite appears during dissolution. The silica formed in the dissolution process is absorbed back and covers some active sites of the particles. The Elovich equation typifies the dissolution behavior of hemimorphite in ammoniacal solution with an activation energy of 57.6 kJ/mol which is characteristic for a chemically controlled process.     

Effect of phosphate on lead removal during a copper recycling process from wastes using ammoniacal chloride solution

Techniques for the removal of lead have been studied in order to develop a hydrometallurgical copper recycling process consisting of copper leaching from wastes using an ammoniacal chloride solution and subsequent copper electrowinning. The solubility of Pb(II) in the ammoniacal chloride solution increased with ammonia concentration; this was attributable to the formation of a lead ammine complex. The lead dissolution was depressed from the order of 10^− 3 M to the order or 10^− 5 M by the addition of phosphate into the leaching solution because of the precipitation of chloropyromorphite (Pb₅(PO₄)₃Cl), while no significant effect was observed by the addition of carbonate. Linear sweep voltammetry and potentiostatic electrolysis in the solution containing Pb(II) revealed that lead was deposited during the copper electrowinning, even in the potential region more positive than the equilibrium redox potential for the Pb/Pb(II) couple on the lead electrode, because of the alloy formation with copper. In a galvanostatic electrolysis, however, the lead content at the electrodeposited copper cathode was found to be lower than 5 ppm at the current density range of 125–400 A/m², when the Pb(II) concentration in the electrolyte was 5 × 10^− 5 M. Since this Pb(II) concentration was achieved by the phosphate addition, these results indicated the effectiveness of phosphate for lead removal in the copper recycling process using the ammoniacal chloride solution.     

Active and passive behavior of sintered iron in ammoniacal ammonium carbonate solution

The anodic dissolution behavior of sintered iron in ammoniacal ammonium carbonate solution (pH = 9.7) has been investigated with the aid of electrochemical techniques. Surface films formed on bulk iron during air exposure or immersion in the ammoniacal solution were characterized by using X-ray photoelectron spectroscopy (XPS). Immersion in the ammoniacal solution gave an apparent open circuit potential (OCP) in the range ofE = 0.04 to 0.09 V, standard hydrogen electrode (SHE); at these potentials, no dissolution of Fe was detected. Potential transients obtained during cathodic reactivation and the XPS results suggest that an air-formed oxide of Fe₃O₄ is responsible for this behavior. The anodic polarization behavior of sintered Fe was similar to that of bulk Fe, showing active, passive, and oxygen evolution regions. A very high current density observed in the passive region for some sintered specimens was attributable to active dissolution within the pore structure, analogous to conditions during crevice corrosion. The presence of oxygen in the solution stabilized both the passive film and the more noble apparent OCP. Formerly Graduate Student, Department of Materials Science and Engineering, Pennsylvania State University Formerly Postdoctoral Research Associate, Pennsylvania State University     

秸秆型生物炭及其对尾矿浸出液中重金属的去除研究

采用芦苇秆、木薯秆和水稻秆3种常见农业废弃物,在中高温下限氧热解,分别制备得到芦苇秆生物炭(RESB)、木薯秆生物炭(CSB)和水稻秆生物炭(RISB),对其理化性质及表面形貌进行了表征,同时考察了不同吸附时间条件下,3种秸秆型生物炭对尾矿浸出液中4种常见重金属元素(Cr、Ni、Cu和Zn)的吸附能力.结果表明:在相同...     

镍电解液用P204萃取除铜

以P204为萃取剂,从镍电解液中萃取除铜。研究了pH、相比(O/A)、P204体积浓度和振荡时间对萃取效果的影响,确定了P204萃取铜的最佳条件。结果表明:随着pH的升高,铜的萃取率增大;相比(O/A)越大萃取分离效果越好;随着P204体积浓度的升高,铜萃取率也相应的升高。室温下P204萃取铜的最佳工艺条件:P204的体积浓度15%,相比(O/A)1∶2,水相初始pH2.0,振荡时间3 min。在此最佳条件下,待处理液的一级萃取率达81.33%。反萃实验中反萃率可达84.97%。     

高膨胀澳洲焦煤的配煤炼焦试验研究

澳洲某矿焦煤具有较高的粘结性和丰富的胶质体,国内大多焦化企业将其作为优质焦煤配用。经煤质分析发现,该矿点焦煤流动度低,仅256ddpm,膨胀度高,坩埚自由膨胀序数(CSN)达9,已达到肥煤指标,煤质非常特殊,配用不当,不仅容易产生大量泡焦,而且对炉墙破坏较大,但其单种煤成焦反应后强度高,可替代少量优质焦煤,配用时需控制配合煤的膨胀度。     

Use of dithionite in the removal of nickel from ammoniacal solutions

An investigation has been carried out to study the feasibility of the removal of nickel from ammoniacal solutions using the reducing agent sodium dithionite. The results obtained indicate that dithionite can precipitate over 95% of nickel values in solution in the form of Ni₃S₂ and metallic nickel. A temperature of 45°C has been found to be optimal for the precipitation process.     

Electrochemical modeling and study of copper deposition from concentrated ammoniacal sulfate solutions

A fundamental investigation of the electrolytic deposition of copper from concentrated aqueous ammoniacal solutions has been carried out based on the thermodynamic analysis of the system Cu–NH₃–H₂O. The speciation of copper vs. pH and redox potential was modeled in high ionic strength solutions, in which the activity coefficients of the system species were estimated according to the Modified Bromley's Methodology. The electrochemical behavior of the redox system Cu(0)/Cu(I)/Cu(II) in concentrated aqueous ammoniacal solutions was studied at pH = 9.5 and the cathodic reactions in these solutions were determined. It was found that metallic copper was formed under strongly reductive redox conditions, while under mildly reductive to mildly oxidative conditions the cuprous di-ammine complex species dominate. Under highly oxidative conditions the cupric tetra-ammine complex species predominated. According to the theory and results, the cathodic deposition of copper from concentrated aqueous ammoniacal solutions proceeds in a two-step reduction mechanism. The cupric ammine species are first reduced to cuprous di-ammine, which in turn is reduced to metallic copper. The electrochemical experiments revealed that copper deposition over time follows a sigmoid-type curve, verifying the two-step mechanism. The main feature of these sigmoid curves was the presence of an induction period with negligible copper deposition, followed by an acceleration period where the copper deposition rate gradually increased. By increasing the applied cell voltage, the induction period was significantly reduced or disappeared.     

从碱渣中提取碲的工艺研究

碱渣是从铅阳极泥中提取贵金属过程中产出的中间物料,其中富集了大量的碲,碱渣中碲主要以亚碲酸钠形态存在.从碱渣的组成和性质出发,利用亚碲酸钠易溶于水、pH值处于中性附近时可转化为二氧化碲的特点,采取碱性湿法冶金技术原理提取碲,其基本路线采用碱渣破碎、球磨、浸出、净化、中和、煅烧、碱溶、电积来得到纯碲.重点研究了浸出时NaOH浓度、浸出时间对碲浸出率的影响,Na2S和CaCl2对Cu,Pb和Si杂质的去除效果,中和沉碲的最佳pH值,煅烧除Se的效果,电积电流密度对电积碲纯度的影响.试验表明,浸出时NaOH最佳浓度为浓度25 g·L-1,最佳浸出时间为4 h,用Na2s,CaCl2除去浸出液中的杂质Cu2+,pb2+和SiO2可以取得理想效果,中和沉碲的最佳pH值为5.0～6.0,最理想的电流密度为50～60 A·m-2.通过对提取碲各阶段试验的数据分析,提出各工艺阶段的控制关键,证实所采用的工艺流程可以从碱渣中成功提取纯碲.     

包头铁水固氧提铌的工艺

提出了用固态氧化剂(轧钢铁皮或高品位铁精矿)从包头铁水提铌的工艺,简称铁水固氧提铌工艺。实验得到了固氧提铌最佳工艺参数:铁水温度为1350℃;W(氧化剂重量/生铁重量)为5%~10%。探讨了非标准状态下,固氧提铌过程铁水中的Nb、Si、Mn、C和P的热力学行为,分析了氧化剂加入量对铁水温度的影响。     

Leaching of a limonitic laterite in ammoniacal solutions with metallic iron

The leaching of a limonitic laterite (containing approximately 1% Ni, 0.1% Co and 50% Fe) was studied in ammoniacal solution. The laterite was leached in the presence of metallic iron which acted as a reductant. The kinetic parameters studied included the effect of temperature, metallic iron concentration, total ammonia concentration and ammonium sulphate to ammonium hydroxide ratios. Tests were performed in a batch cell with temperature ranging from 50 to 80 °C at atmospheric pressure. The kinetic behavior for nickel and cobalt extraction was observed to be different. Cobalt extraction was initially faster than nickel and it showed good extractions at lower temperatures, however, after reaching a maximum value of approximately 80%, extraction decayed by as much as 50%. This was likely due to cobalt co-precipitation and/or adsorption into iron and/or manganese oxides and hydroxides which could form during the process. Cobalt losses tended to increase with temperature, total ammonia concentration, ammonium hydroxide to ammonium sulphate ratio and metallic iron concentration. Nickel extraction was increased by higher temperature, total ammonia concentration and metallic iron concentration up to a maximum of roughly 70% after 48 h at 80 °C.Through feed and solid residue analysis, by X-ray diffraction and SEM, it was possible to characterize and understand how the feed mineral reduction occurred. The main phases present in the feed and residue were goethite and magnetite, respectively. Results suggest that the reduction occurs through two main reactions. First, the reaction between goethite and metallic iron produced Fe(II) ammines. The Fe(II) ammines are capable of reducing goethite and producing magnetite. The Fe(II) ammines play an important role because they accelerate the reduction and favor the extraction kinetics of nickel. The main advantage of using metallic iron as a reducing agent is the possibility of generating an autocatalytic system.     

硫代硫酸铵法从焙烧后的某含铜硫金精矿中回收金

研究了硫代硫酸盐法从焙烧后的含铜硫金精矿中回收金的工艺过程,研究了表明,焙烧前金的回收率很高,焙烧后,常温下硫代硫酸盐浸出,既可是较好的金浸出指标,又可降低硫代硫酸耗量。     

从锆英石提取钪的研究

锆英石是钪的重要来源之一,本文叙述了从ZrOCl_2结晶母液中提取钪的方法,此法主要包括磷酸沉锆,P204萃取,HCl洗涤,NaOH反萃及精制等过程。     

从富铟渣提取金属铟的研究

对一种含铟渣进行了提取金属铟的条件和工艺研究,研究了酸度、液固比、时间等因素对铟浸出率的影响,不同酸度下铟及其他杂质的行为走向,置换剂的选择及置换的工艺条件的探索。研究结果表明,控制合适的工艺条件:中性浸出液固比6~8∶1,温度80℃,时间4~6h;酸性浸出液固比8∶1,温度80℃,浸出时间为8~10h;锌粉置换温度≥20℃,时间72h,pH1~1.5,锌粉粒度80~120目可以高效地提取渣中的铟。确定了从这种渣中提取金属铟的工艺流程,并将其用于了生产实践,铟的回收率大于85%,取得了较好的生产效果和经济效益。