从废弃印刷线路板中回收金的试验

试验研究了采用硫脲法有效地从废弃印刷线路板中回收金.试验结果表明,硫脲回收金的主要影响因素有温度、硫脲质量浓度、Fe3+质量分数、浸出时间、硫酸体积分数;合适的浸出条件是固液比为15,浸出温度为35℃,硫脲质量浓度为10g/l,Fe3+质量分数为0.3%,浸出时间为1h,硫酸体积分数为5%.     

卡林型金矿的HClO4-FeCl3浸出及正交试验研究

采用HClO4预氧化、FeCl3进一步氧化络合方法联合浸出品位低、成分杂的卡林型金矿中的金。机理分析认为，在浸出前期加入HClO4将金属硫化物中的硫以高价态硫酸根离子、硫酸氢根离子等形式进入溶液而脱除，减少单质硫形成钝化膜包裹从而阻碍金属硫化物的解离，同时保证体系中一定初始浓度的[Fe³⁺]、[Cl^-]，有利于后续FeCl3浸金。正交试验研究表明，选定的4个因素对金浸出率的影响顺序为HClO4体积分数＞FeCl3浓度＞浸出温度＞HClO4预氧化时间，得到的较优浸出条件为HClO4体积分数6%、预氧化时间1 h、FeCl3浓度1.8 mol/L、40℃浸出5 h，在该条件下卡林型金矿金的浸出率为71.02%。     

硫脲-硫氰酸钠浸出难处理金矿及浸出剂的稳定性

采用高温焙烧、硫脲-硫氰酸钠浸出难处理金矿中的金,研究焙烧温度、硫氰酸钠浓度、硫脲(Tu)浓度、Fe3+浓度、pH值、浸出温度和时间对金浸出率的影响,得到混合体系浸金的最优条件,并研究浸出过程中硫氰酸钠和硫脲的稳定性。结果表明:金的浸出率达到93.1%,超过相同条件下单一体系中的浸出率之和,硫脲与硫氰酸钠摩尔比对金浸出率和金电极稳定电位影响较大;硫氰酸钠使硫脲的稳定性降低,而硫脲使硫氰酸钠的稳定性增强。     

赤泥酸浸的试验研究

以HCl和H2SO4为浸出剂,对赤泥中各有价金属的浸出条件进行了较系统的试验研究。结果表明,先采取低浓度HCl浸出,残渣再用高浓度H2SO4分解的两段浸出方式为佳。一段浸取盐酸浓度为6mol／L．液固比L／S=4：1．反应温度50℃,反应时间1h。Sc2O3的浸出率大于80％,TiO2的浸出率为1％左右。二段浸取硫酸浓度为92％．酸渣比为3：1．熟化温度为200℃,熟化时间为1．5h。TiO2的浸出率为96．57％。     

采用中温菌和常温菌浸出含砷金精矿

考察了不同矿浆浓度和接种量对细菌浸出含砷金精矿的影响。结果表明：中度嗜热嗜酸铁氧化菌MLY和嗜酸氧化亚铁硫杆菌（Acidthiobacillus ferrooxidans,At.f）的浸矿效果不同。MLY和At.f对含砷金精矿的浸出机理也不同;接种MLY的矿浆中,可能主要是溶液中的细菌将Fe^2＋氧化为Fe^3＋,再由Fe^3＋氧化溶解矿物,即以间接浸出作用为主;而接种At.f可能首先是At.f被吸附到矿物表面,通过细菌与矿物之间的某种界面作用引起矿物溶解,矿物溶解产生的Fe^2＋被游离菌氧化成为Fe^3＋,从而溶解矿物,即At.f浸出可能包括直接作用和间接作用的共同效应。     

四川丹巴铜炉房金矿床矿石选冶方法研究

通过多次对金矿石的选冶试验研究工作,使金精矿经沸腾焙烧预处理后Au、Ag、Cu、S的浸出回收率均得到显著提高,其中硫脲法Au、Ag、Cu的浸出率分别为99.4%、95.8%、98.0%;氰化法 Au、Ag、Cu的浸出率分别为:99.4%、89.4%、93.3%.最终确定矿石的最佳选冶方案为:原矿破碎→球磨→浮选富集→金、银、铜精矿→沸腾焙烧→烟气制硫酸,焙砂经硫酸浸出萃取电解回收铜后,再经硫脲法回收金银.     

铜渣中有价金属酸溶出试验研究

利用硫酸溶出铜渣中的有价元素,研究了常压下硫酸体积分数、浸出时间、浸出温度和硫酸用量(固/液比)对铜渣中Fe、Cu、Co和Ni的溶出率及溶出速率的影响。结果表明:随着硫酸体积分数的升高,促进了硅酸凝胶在酸液中的形成,吸附浸出液中的金属离子,导致了溶液中各金属的溶出率有所降低;浸出温度的升高有助于提高铜渣中金属元素的溶出率。通过试验研究获得了铜渣中有价金属浸出的最佳条件:硫酸体积分数20%,硫酸用量为理论用量的7倍,浸出温度90℃,浸出时间2 h,此条件下Fe、Cu、Co和Ni的溶出率分别达到94.5%、69.7%、73.9%、36.4%。     

含砷黄铁矿中金的浸提性质

某地含金黄铁矿含砷量高,不宜氰化处理,因而大量积存。为寻找适宜的工艺流程,我们对该矿中金在酸性硫脲溶液中的溶解性质进行研究。实验表明,当将原矿研磨至-150目后,在800℃下焙烧1小时,按固:液=1:4,以浓度1％、硫酸介质pH=1的硫脲作溶剂,在室温和不断搅拌中,进行二段浸提6小时,原高砷矿金的浸出率达95.4％,渣率90％;原低砷矿金的浸出率达96.7％,渣率95％。较高的渣率说明,在本试验确定的条件下,硫脲对金的选择性良好,矿中银的溶解较差。     

氰化尾渣还原焙烧酸浸提铁及氰化浸金新工艺

以氰化尾渣为原料,采用还原焙烧酸浸工艺对其进行处理。当还原温度为850℃、加入煤粉质量为氰化尾渣质量的13%、还原时间为100 min时,对氰化尾渣进行还原,氰化尾渣中Fe2O3转化为Fe3O4或FeO。还原后采用硫酸浸出,当硫酸浓度为50%、硫酸用量系数为1.2、反应温度为105℃、反应时间为3 h时,铁的浸出率达到93.66%。还原焙烧渣在600℃氧化焙烧2 h经过脱碳后氰化浸金,当氰化钠用量为4 kg/t、反应时间为28 h、液固比为2:1时,金的浸出率达到92.4%。经过还原焙烧、硫酸浸出、氧化焙烧及氰化浸金,氰化尾渣渣量减少了38.8%。     

铁矾渣热酸分解及硫脲提银

进行铁矾渣热硫酸分解和分解渣硫脲法提银的试验研究,考察硫酸用量、分解温度、反应时间、液固比对铁矾渣中Fe、Zn、Ag浸出率的影响,以及硫脲法提银的最优条件。结果表明:在硫酸用量为其理论值的1.5倍、分解温度95℃、时间2.5 h、液固比2.5:1的最佳条件下,铁矾渣中Fe和Zn浸出率分别为93.85%和92.25%,而Ag的浸出率仅为1.99%。分解液净化后可用中温水热法制备铁红,分解渣中Ag富集到1060 g/t。在液固比10:1、硫脲浓度15 g/L、浸出温度90℃、反应时间2.5 h的最优条件下,Ag的平均浸出率在93%以上,同时,渣中Pb的品位由1.7%提高到7.5%。     

Dissolution kinetics and thermodynamic analysis of vanadium trioxide during pressure oxidation

The dissolution kinetics of vanadium trioxide in sulphuric acid-oxygen medium was examined. It was determined that the concentration of sulphuric acid and stirring speed above 800 r min 1 did not significantly affect vanadium extraction. The dissolution rate increased with increasing temperature and oxygen partial pressure, but decreased with increasing particle size. The dissolution kinetics was controlled by the chemical reaction at the surface with the estimated activation energy of 43.46 kJ·mol-1. The l...     

还原酸浸法从低品位水钴矿中提取铜和钴

以Na2SO3为还原剂从水钴矿还原酸浸液中提取铜和钴,研究了还原剂种类及用量、浸出温度、硫酸浓度等因素对水钴矿还原酸浸过程中有价金属铜和钴浸出率的影响。结果表明,Na2SO3是较适宜的还原剂;在还原剂用量为水钴矿原矿质量的10%、硫酸浓度为3 mol/L、浸出温度为60℃、液固比为2-1、浸出时间为60 min的条件下,铜和钴的浸出率分别达99.06%和98.87%。并提出了"M5640萃铜→黄钠铁矾法除铁→碳酸钠除铝→氟化钠除钙、镁→蒸发结晶得钴产品"的后续分离净化流程,能有望应用于水钴矿及类似物料中有价金属的提取与分离的工业生产。     

Preparation of solid polyferric sulfate from pyrite cinders and its structure feature

1　INTRODUCTIONCoagulationisanessentialprocessintheoverallsolid liquidseparationschemeinwaterandadvancedwastewatertreatment .Hydrolyzingmetalsalts ,suchasferriccoagulants ,canpromotetheformationofag gregates.WhenFesaltsaredissolvedinwater,themetalironhydrates ,coordinatingsixwatermoleculesandforminganaquometalion ,canthenhydrolyzeandformmonomericand polymericferricspecies ,whichishighlydependentonpHofthesolution .Itispossibletodescribetheformationofseveralhydrolysisspecies ,suchaspositiv…     

DISSOLUTION THEORY OF GOLD IN ALKALINE THIOUREA SOLUTION(I) Anodic Behavior on Gold in Alkaline Thiourea Solution Containing Na2SO3

Anodic polarization behaviors of gold and its associated elements, e.g., silver, copper, nickel and iron, in the alkaline thiourea solution with and without Na2SO3 were examined. The results showed gold is hardly dissolved in the solution with Na2SO3 because of the passivation of elemental sulfur produced by irreversible decomposition of alkaline thiourea; however, the additive Na2SO3 improves the stability of thiourea in alkaline media, greatly increases anodic current of gold and accelerates the selective dissolution of gold in the alkaline thiourea solution, without changing the passivation states of the associated elements of gold. Also the factors affecting the polarization of gold anode were investigated in detail, and it was found that, the Na2SO3obviously decreases polarization potential of gold and the apparent activation energy of gold dissolution, and the controlling step of the dissolution of gold anode in the alkaline thiourea solution is changed from the anode dissolution reaction to the solute diffusion. The mechanism for accelerated dissolution of gold in the alkaline thiourea solution with Na2SO3 was considered as electrochemical reduction and catalysis, over the Na2SO3 concentration of 0.01 ～0.5 mol/L, at the potential of 0.34～0.44 V.     

硫氰酸盐光度法测定氨浸渣中的钼

将氨浸渣试样用硝酸-硫酸-磷酸混合酸溶解-氢氧化钠分离,2 mol/L的硫酸介质中,在Cu~(2+)催化下,以硫脲将Mo(Ⅵ)还原为Mo(Ⅴ),与硫氰酸盐生成琥珀色配合物,借此进行光度法直接测定.重点研究样品的分解方法、共存元素的干扰以及干扰消除方法等.并采用重量法、全差式光度法和硫氰酸盐直接光度法(本法)3种分析方法,对同一试样分别独立地进行8次测定,将测定结果进行比较.结果表明:本法操作简便,分析结果有较高的精密度、准确度,对氨浸渣中钼的测定达到满意的效果,优于钼酸铅重量法.     

硫脲浸金电化学行为研究

采用循环伏安法(CV)、Tafel曲线和差分脉冲伏安法(DPV)等电化学方法对模拟硫脲浸金体系进行了研究.结果表明,硫脲浓度范围为0.005～0.04 mol/L,浓度增大有利于金的浸出;在Fe3+浓度为0.01～0.08 mol/L范围内,随着Fe3+浓度的增大,金腐蚀电位负移,腐蚀电流变大;适度升温可以提高金的腐蚀...     

Dynamics of anodic process of gold electrode in thiourea solution in the presence of sulfur dioxide

1　INTRODUCTIONCyanidefreetechnologyofgoldextractionisanimportantissueinhydrometallurgy[1,2 ] .Thioureawasusedasanimportantmetallurgicalreagentduetoitsgoodselectivity ,low poisonousnessandhigheffi ciency[3,4 ] .Refs .[5 7]showedthatanodedissolv ingofgoldwillbeacceleratedifsulfurousacidorsul furdioxide (H2 SO3)isaddedintothioureasystem .Themechanismwasconsideredthatsulfurousacidwasinvolvedintotheelectrochemistryreactionofthesystem ,mainlyacceleratingdeoxidizationreactionofformamidinedisul…     

Anodic dissolution of gold in alkaline solutions containing thiourea, thiosulfate and sulfite ions

Gld dissolves electrochemically in alkaline solutions containing ligands to form complex ions with gold ion.Therefore,selective leaching of noble metals is expected without dissolution of base metals such as steels,aluminum alloys in scrap treatment.Gold electrodes were investigated using linear sweep voltammetry,EQCM method and potentiostatic eclectrolysis in alkaline solutions containing thiourea,Na2SO3 and Na2S2O3.The solution composition,electrode potential affect gold dissolution rate and current efficiency.The gold dissolved from anode electrode forms complex ions,suspension particles as compound precipitates and deposits on cathode electrode as a metal.Anodic efficiency for gold dissolution is between 10% and 22%.This is caused by the oxidation decomposition of sulfite ions and thiourea.The statbility of the alkaline solution containing these elements was also estimated by capillary electrophoresis technique.     

KINETICS OF LEACHING SPHALERITE WITH PYROLUSITE SIMULTANEOUSLY BY MICROWAVE IRRADIATION

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DISSOLUTION THEORY OF GOLD IN ALKALINE THIOUREA SOLUTION(Ⅱ)——Electrochemical Study on Au-Fe Mix Anode in Alkaline Thiourea Solution Containing Na_2SO_3

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