金银硫脲络合物结晶的溶解度曲线

本研究测定了金、银硫脲络合物的溶解度曲线,它给结晶法分离金、银提供了理论依据。所测得的溶解度曲线指出,金硫脲络合物一般都比银硫脲络合物易溶解,硫脲合金(或银)的硫酸盐较其它的盐(如氯化物和硝酸盐)难溶解。还进一步指出金、银的结晶分离中硫酸是较为有利的介质。     

酸性硫脲溶液中金银分离的研究(Ⅱ)(沉淀法)

本文依据酸性硫脲溶液中金较银易于形成硫化物沉淀的性质,利用硫脲的酸碱分解性,恰当地控制溶液pH值,在存有添加剂条件下,原作为浸出剂的硫脲可转作为沉淀剂。文中给出了分离的最佳工艺条件:pH为6～7,硫脲浓度为40～45克/升,室温,适中搅拌15～20分钟。分离因子3850。     

硫脲法从废旧电路板中浸取金、银的研究

废旧电路板中含有丰富的可回收金属Cu,Au,Ag,Pt,Pb等,其处理处置、无害化、资源化成为经济发展中急需解决的问题。采用硫脲法对废旧电路板中的金、银进行浸取实验,主要考察了反应时间、反应温度、硫脲浓度、Fe3＋的质量浓度、物料粒度对金及银浸出率的影响。结果表明,在最佳浸取条件下,金、银都能达到理想的浸取效果,金和银的最高浸取率分别达到90.87%和59.82%。硫脲提金法因溶金速度快,浸出时低毒、价格低廉、高效、有利于环保、干扰离子少等优点而成为取代氰化提金的绿色浸金方法。     

硫脲法从锌的酸浸渣中回收银

研究了从湿法炼锌酸浸渣中用硫脲浸出银的工艺及机理，对浸出过程中的各种影响因素如矿浆浓度、浸出剂浓度、反应温度、反应时间、ＰＨ值等分别进行了试验研究和分析讨论，给出了最佳工艺条件，在此条件下，银浸出率达８９％。     

酸性硫脲溶液中金、银分离的研究(Ⅲ)(结晶法)

经试验证明,用降温结晶法从酸性硫脲溶液分离金和银,乃是一种有效的方法。实验获得了在硫酸硫脲溶液分离金、银的较优工艺条件:pH1.5,金浓度<1000毫克/升,银含量越高越好,游离硫脲浓度3克/升,结晶温度0℃,结晶时间25分钟左右,结晶产物灼烧后金属纯度达99%以上。     

用阻抗法研究硫脲对稀盐酸中铁的缓蚀作用

测量了１ｍｏｌ／ＬＨＣｌ＋ｘｍｍｏｌ／ＬＴＵ（ｘ＝０，０．１，０．５，１，２，４）中铁的电极阻抗和稳态极化曲线，对铁在上述溶液中的腐蚀机理进行了分析，并建立了铁电极阻抗的等效电路，实验结果表明硫脲不改变１ｍｏｌ／ＬＨＣｌ中铁的腐蚀历程，它主要通过铁腐蚀反应中间产物的吸过程的作用来影响铁的腐蚀行为。     

磁场强化硫脲提金技术的热力学研究

与常规硫脲浸金相比,磁场强化硫脲浸金可得到更高的浸金率,且金的溶解速度更快．根据不同温度下的浸出试验结果,利用Ａｒｒｈｅｎｉｕｓ公式计算了体系浸出的表现活化能,计算结果表明磁场强化使硫脲浸取高砷金精矿体系的表现活化能由１３．０２ｋＪ／ｍｏｌ降至１０．５３ｋＪ／ｍｏｌ．此外,还从热力学的宏观角度与微观角度讨论了磁场强化硫脲提金工艺的强化作用机理．     

001A强酸性树脂吸附硫脲金的研究

研究了强酸性苯乙烯系阳离子交换树脂００１－Ａ在ｐＨ＝ ２．０的Ｈ２ＳＯ４－ ＣＳ（ＮＨ２）２－ Ｈ２Ｏ２ 体系中,吸附、富集硫脲金的性能。结果表明,该树脂对硫脲金离子Ａｕ（Ｔｕ）＋２ （Ｔｕ＝ 硫脲）具有吸附率高,吸附容量大等优异性能。Ａｕ 负载柱可用Ｎａ２Ｓ２Ｏ３ 溶液定量洗脱,用过的树脂可再生。     

活性炭自硫脲溶液吸附金的氧化还原机理探讨

采用X射线衍射、元素分析及显微技术等方法,研究了活性炭(AC)自溶液中吸附金硫脲络合物的机理。研究发现,溶液中络合离子被活性炭表面的≥C-OH和≥C-H官能团还原为零价金Au(0)而吸附;提出了氧化还原吸附机理可能的步骤,并用Nernst公式证明该氧化还原吸附过程为自发过程。     

Fenton试剂法处理偶氮类染料废水的实验研究

为了评价Fenton试剂(Fe2+-H2O2)法处理高浓度偶氮染料废水的可行性,对天津市某厂经纳滤处理后的染料废水进行处理,研究了pH值、H2O2投加量、Fe2+投加量、反应时间、H2O2投加方式等因素对废水CODCr去除效果的影响.结果表明:在H2O2(质量分数为30%)投加量为12.5 mL/L、pH值为3、Fe2+与H2O2的摩尔比为1∶10、反应时间为6 h、分批次投加H2O2的最佳运行条件下,CODCr去除率达到81.3%,处理效果较理想.     

Mechanism of gold dissolving in alkaline thiourea solution

Reaction mechanism of gold dissolving in alkaline thiourea solution was studied by electrochemical methods,such as cyclic voltammetry,chronopotentiometry,AC impedance,linear sweep voltammetry.Apparent activation energy of anodic process of gold electrode dissolving in alkaline thiourea solution is 14.91 kJ/mol.Rate determining step is the process of gold thiourea complex diffusing away from electrode surface to solution.The results of AC impedance and chronopotentiometry indicate that thiourea adsorbs on gold electrode surface before dissolving in solution.There does not exist proceeding chemical reactions.Formamidine disulfide,the decomposed product of thiourea,does not participate the process of gold dissolution and thiourea complex.Species with electro-activity produced in the process of electrode reaction adsorbs on the electrode surface.In alkaline thiourea solution,gold dissolving mechanism undergoes the following courses:adsorption of thiourea on electrode surface;charge transfer from gold atom to thiourea molecule;Au[SC(NH2)2]ads receiving a thiourea molecule and forming stable Au[SC(NH2)2]2 ;and then Au[SC(NH2)2]2 diffusing away from the electrode surface to solution,the last step is the rate-determining one.     

Study on mechanism of gold leaching by thiourea in the presence of sodium sulphite

Ｃｙａｎｉｄａｔｉｏｎｈａｓｂｅｅｎｕｓｅｄｆｏｒｍｏｒｅｔｈａｎｏｎｅｈｕｎ ｄｒｅｄｙｅａｒｓｉｎｇｏｌｄｉｎｄｕｓｔｒｙｓｉｎｃｅｔｈｅｆｉｒｓｔｐａｔｅｎｔｂｙＭａｃＡｒｔｈｕｒａｎｄｔｈｅＦｏｒｒｅｓｔｓｉｎ 1889[1] ,ａｎｄｓｔｉｌｌｒｅｍａｉｎｓｔｈｅｍｏｓｔｐｏｐｕｌａｒｏｐｔｉｏｎｆｏｒｐｒｏｃｅｓｓｉｎｇｇｏｌｄｏｒｅｓｂｅｃａｕｓｅｏｆｉｔｓｐｒｏｃｅｓｓｓｉｍｐｌｉｃｉｔｙａｎｄｏｐｅｒａｔｉｏｎｅｃｏｎｏｍｙ .Ｎｅｖｅｒｔｈｅ ｌｅｓｓ,ａｐｐｌｉｃａｔｉｏｎｏｆｔｈｅｔｅ…     

液珠萃取比色法测定化探样品中的金、银

在10%HCl介质中,采取用二苯硫脲(DPTU)-甲基异丁酮(MIBK)泡沫塑料富集,以金试剂液珠萃取比色法,连续测定化探样品中Au和Ag.该方法机理在于当富集Au和Ag的DPTU-MIBK泡塑灰化后,用1+1HNO3溶解Ag,Au不溶于HNO3而留在残渣中.利用吸管吸取Ag的有色液珠,可将Au和Ag分离.方法的检出限(10g称样):Au0 5×10-9,Ag5×10-9.     

Optimization of efficient stable reagent of alkaline thiourea solution for gold leaching

1　INTRODUCTIONThiourea ,asanontoxic goldleachingreagentsubstitutingcyanide ,hasattractedtheinterestofmanyresearchersallovertheworldsincethedissolu tionofgoldinthioureasolutionwasfirstreportedin194 1,andaseriesofstudiesonthetheoryandtech nologyforleachinggoldbythioureahavebeencon ducted[1 3] .Mostreportson golddissolutioninthioureasolutionwereconcernedwithacidicmedia .Itwasdifficultforgoldtodissolveinalkalinesolutionbecauseofthepassivationofelementsulfurproducedbytheirreversibledecompositi…     

五台山-恒山一带金、银多金属矿床同位素地球化学及其成矿模型

通过同位素地球化学研究，五台山—恒山—带金、银多金属矿床的硫源均来自深源；铅同位素组成表明成矿物质主要来自下地壳及地幔，但绿岩型金矿铅同位素变化较大，而燕山期次火山岩型金、银多金属矿床铅同位素较为集中；运移形成矿物的水源也有所不同，前者是以变质水为主(δ^18OH2O1.34％-12.55％,δD-22.287％—--177.36％)，后者则是以岩浆水及天水混合为主(δ^18OH2O多在-18．6‰～ 10．05‰，δD-68‰～-110‰)；碳氧同位素组成也揭示了前者以变质作用为主(δ^13C(PDB)-1.25‰～1.37‰，δ^18O(SMOW)11．4％～16．5％)，后者与花岗斑岩侵入有关(δ^13C(PDB)为-4．0‰～-9．2‰，δ^18O(SMOW)3．5‰～9．6‰)；两类矿床的锶同位素比值，也反映了与成矿作用有着密切关系的太古宙斜长角闪岩和燕山中期花岗斑岩均是壳幔混合产物，故可视为两类矿床有着内在成因联系；钐-钕同位素组成不仅获得相同结论，而且从εNd(0)和∫sm／Nd均是负值，推测属大陆地壳岩石，可能为O-C型绿岩地体的成矿背景，从而建立了五台热幔柱构造的成矿模型，试图指导找矿。     

Locating mechanism study of several types of gold deposits

Based on the availabities of three ore-controlling factors, the authors put forword the locating mechanism of gold deposits. The model experiment indicates that the pressure-release effect occuring during the locating process marks the metallogenic nonlinear effect and causes the formation of deposits. In addition, the deposits involved in this paper can be divided into four kinds of locating mode. Synopsis of the first author Li Peilan, professor, born in 1938, majoring in mineralogy, ore deposit, experimental mineral-rock and applied geochemistry-thermodynamics, has published more than 50 papers and books, such as ?Geological chemistry-thermodynamics?.     

Cyanidation of gold clay ore containing arsenic and manganese

The extraction process of gold and silver from the gold clay ore containing arsenic and manganese was investigated.With the conventional technique,the leaching rates of gold and silver are 78.23%and 49.02%,respectively.To eliminate the negative effects of arsenic and manganese on cyanidation and increase the gold and silver leaching rates,a novel catalyst was added.The content of the catalyst used in the process was 8 g per 500 g org sample,the sample size was 60μm and the pH value was kept between 10 an...     

Beneficiation of the gold bearing ore by gravity and flotation

Gold concentration usually consists of gravity separation, flotation, cyanidation, or the combination of these processes. The choice among these processes depends on the mineralogical characterization and gold content of the ore. Recently, the recovery of gold using gravity methods has gained attention because of low cost and environmentally friendly operations. In this study, gold pre-concentrates were produced by the stepwise gravity separation and flotation techniques. The Knelson concentrator and conventional flotation were employed for the recovery of gold. Gold bearing ore samples were taken from Gümüshane Region, northern east part of Turkey. As a result of stepwise Knelson concentration experiments, a gold concentrate assaying around 620 g/t is produced with 41.4wt% recovery. On the other hand, a gold concentrate about 82 g/t is obtained with 89.9wt% recovery from a gold ore assaying 6 g/t Au by direct flotation.     

宁夏中部干旱区马铃薯种薯耗水规律及水分效应研究

通过开展马铃薯种薯覆膜与露地滴灌田间试验,研究水分对马铃薯种薯产量的影响及马铃薯耗水规律.结果表明:覆膜地马铃薯种薯产量极显著地高于露地马铃薯种薯产量;不灌水处理马铃薯种薯产量极显著地低于其他各灌水处理,灌溉定额越大,马铃薯种薯产量越高;灌溉定额一定,产量、耗水量和耗水模系数及水分利用效率均呈灌水2次>灌水1次>灌水3次的规律;灌溉定额越大的处理耗水量越大,在全生育期马铃薯的耗水规律为现蕾期>花期>苗期>成熟期,现蕾期耗水量最大.露地比覆膜耗水量大18.43 mm,膜下滴灌马铃薯的水分利用效率明显高于露地,说明膜下滴灌马铃薯技术有利于保持土壤水分,有效节约水资源,适宜在宁夏中部干旱地区广泛推广.     

超临界机组附加单耗分布及案例分析

建立了超临界机组稳态工况下能耗空间分布模型,基于600 MW超临界机组锅炉及汽轮机系统模型进行案例分析。根据热力学第二定律,得出总体附加单耗在各设备间的分布情况,挖掘出节能潜力并提出进一步降低煤耗的指导思路。