砷碱渣稳定化处理合成臭葱石晶体固砷

砷碱渣中含有剧毒可溶性砷化合物,若不妥善处置,易造成水体污染和生物中毒。本研究目的是将砷碱渣中的砷转化为大颗粒晶型臭葱石以利于安全储存。在制备臭葱石晶体的反应中,考察了初始pH值、Fe/As摩尔比和反应温度对沉砷率及臭葱石形成的影响,并探究了不同条件下得到的沉淀的浸出毒性。结果表明:当初始pH值为1.0～2.0、Fe/As摩尔比为0.5～3.0及反应温度为105～175℃时,沉砷率可达80%以上,所得臭葱石晶体的As浸出浓度低于5 mg/L。在初始pH值为1.5、Fe/As摩尔比为1.0及反应温度为150℃的优化条件下,得到的臭葱石晶体呈八面体形状,颗粒尺寸可达20μm,且As浸出浓度低至0.08 mg/L,适于稳定化处理砷并长期安全储存。     

含镉烟灰在酸性介质中的浸出行为及过程优化

对含镉烟灰的物相组成进行了系统分析,并提出针对性的工艺流程。针对硫酸浸出含镉烟灰的过程,采用响应曲面设计方法对操作条件进行了优化,考察了反应温度、液固比、硫酸浓度及其交互作用对Cd、As、Zn浸出率的影响关系,构建了二阶数学模型和三维响应曲面图,确定了Cd、Zn、As的浸出率分别大于92%、95%和50%的优化浸出条件区域,即反应温度25～60℃,液固比6～8 mL/g,硫酸浓度0.3～0.4 mol/L。结果表明:该模型能够准确预测含镉烟灰在硫酸中的浸出效果;在最优区域内,As的浸出率较低,其主要原因是原料中的砷酸锌在低酸条件未分解。     

Accelerating column leaching trial on copper sulfide ore

The main measures to accelerate leaching sulfide ore are large spraying intensity,manual oxygen supply,temperature control,and acclimated bacteria.The indoor experiment accelerating sulfide ore leaching detected the temperature during leaching process,dissolvability of oxygen,bacterial concentration,Cu concentration and slag grade.At the same time,this paper also analyzed the effect of four factors,which are bacterial diversity cultivation stage,spraying intensity,air supply,and whether to control temperature,on the leaching efficiency of copper.The results indicate that the oxygen content of leach solution has a close relationship with temperature but it is rarely affected by air supply.The bacterial concentration preserves from 106 to 107 mL^-1,and temperature has a great effect on the bacterial activity under the condition of proper temperature and oxygen supply,and the lack of nutrition prevents the bacterial concentration from rising in the late stage.The relationships of the copper leaching efficiency to temperature,air feed,and spraying intensity are directly proportional.The leaching efficiencies of the cultivated bacteria and acclimation bacteria are 1.2 and 1.4 times as large as that of the original bacteria.     

Evaluation of the resistance of mortars coated with silver bearing zeolite to bacterial-induced corrosion

An evaluation of the resistance of mortar specimens coated with silver bearing zeolite to biologically produced sulphate and their antimicrobial characteristics was carried out in this study using Acidothiobacillus thiooxidans. The evaluation was performed based on leaching Ca²⁺ and Si⁴⁺ from the cementitious matrix, rate of bacterial sulphur oxidation, increase in biomass concentration, and acid production. The cumulative concentration of Ca²⁺ leaching were 3.5-folds higher (28.5 mg Ca²⁺/g cement) and 2-folds higher (18 mg Ca²⁺/g cement) in the uncoated and epoxy coated mortar specimens compared to those of zeolite coated specimens (9 mg Ca²⁺/g cement and 8 mg Ca²⁺/g cement for type AC and AK respectively). The cumulative leaching Si⁴⁺ was also 2.6-folds higher in the control mortar specimens (0.65-1.8 mg Si⁴⁺/g cement). Biomass concentration in the control specimens reached 210 mg TSS/L, and that of the zeolites coated mortar specimens was 103 mg TSS/L. The bacterial sulphur oxidation was found to follow the same pattern of the bacterial concentration, 230-270 mg SO₄/g S and 158-182 mg SO₄/g S in the control and zeolite coated mortar specimens, respectively. The resistance of the zeolitic coating was further evidenced by the increase in pH of the control mortar specimens which demonstrated the leaching of Ca (OH)₂ from the cement matrix. The stability of zeolite coated specimens was confirmed by the absence of corrosion products as was examined by FE-SEM and XRPD.     

用碱性Na_2EDTA溶液从次氧化锌烟灰中选择性回收铅(英文)

采用碱性Na2EDTA溶液从次氧化锌烟灰中回收铅。探讨温度、浸出时间、Na2EDTA浓度和起始NaOH浓度对铅、锌浸出率的影响。得到最优实验条件如下:液固比5:1 mL/g、搅拌速度650 r/min、Na2EDTA浓度0.12mol/L、NaOH初始浓度0.5 mol/L、温度70°C、浸出时间120 min。在最优实验条件下,铅、锌、氟和氯的平均浸出率分别为89.92%、0.94%、62.84%和90.02%。浸出液用于电沉积铅粉。在温度为60°C、电流密度为200A/m2、H3PO4浓度为1.5 g/L、铅离子浓度不低于5 g/L时,电沉积铅粉平均电流效率大约为93%,阴极铅纯度高于98%。电沉积1 kg铅粉大约消耗0.218 kg Na2EDTA和0.958 kW·h电能。     

Effect of As(III) on kinetics of Fe2+ bio-oxidation

Fe²⁺ bio-oxidation influenced by toxic metal ions released from the dissolution of arsenic-bearing gold ores was investigated. Fe²⁺ bio-oxidation by moderately thermophilic microorganisms was studied under different initial concentrations of Fe²⁺ and As(III), and Monod equation was used to fit the Fe²⁺ bio-oxidation under different conditions. Results showed that the Fe²⁺ bio-oxidation rate increased as the initial Fe²⁺ concentration increased until it reached 12 g/L. As(III) severely inhibited Fe²⁺ bio-oxidation. When the As(III) concentration was 8 g/L, 9 g/L Fe²⁺ was more than 200 h. The Monod equation fitted the Fe²⁺ bio-oxidation well. In the absence of As(III), the maximum specific growth rate of the culture and the substrate affinity constant were 0.142 h^-1 and 0.053 g/L, respectively. As(III) inhibited Fe²⁺ bio-oxidation via competitive inhibition, and the inhibition constant was 0.0035 g/L.     

铜电解过程中As(Ⅲ)净化作用及其氧化动力学

研究铜电解过程中As(Ⅲ)初始浓度对电解液净化的影响及其氧化动力学。结果表明:当电流密度为235A/m2、电解时间为168 h、电解液中As(Ⅲ)初始浓度为0时,总As浓度(TAs)从10.00 g/L增加至10.62 g/L,Sb的浓度从0.40 g/L增加至0.45 g/L,Bi的浓度从0.22 g/L增加至0.24 g/L;当As(Ⅲ)初始浓度为5.00 g/L时,As(Ⅲ)从5.00 g/L下降至1.80 g/L,TAs从10.00 g/L下降至9.70 g/L,Sb的浓度从0.40 g/L下降至0.26 g/L,Bi的浓度从0.22 g/L下降至0.18 g/L;当电流密度为235 A/m2,电解时间为144 h时,As(Ⅲ)的浓度从7.62 g/L下降至3.71g/L,TAs浓度约为11.16 g/L,Sb的浓度从0.22 g/L微增至0.26 g/L,Bi的浓度为0.086 g/L。在铜电解过程中,As(Ⅲ)能够抑制电解液中TAs、Sb和Bi的浓度的增加,具有净化铜电解液的作用;As(Ⅲ)不断被氧化,其氧化反应符合一级反应动力学规律,活化能为46.11 kJ/mol。     

难冶金精矿烟尘中铁砷碳的脱除对氰化浸金的影响

以难冶金精矿烟尘为原料,研究了氢氧化钠浸出、硫酸浸出以及硫酸与氢氧化钠联合浸出对烟尘中砷、铁和碳脱除及氰化浸金的影响。结果表明:在氢氧化钠浓度为6mol/L时,砷、碳脱除率分别为99.66%和60.63%,金浸出率为58.90%,较直接氰化浸出仅提高4.60%,砷的有效去除不能有效提高金的浸出率。在硫酸质量分数为15%时,铁、砷和碳脱除率分别为33.65%、80.38%和12.59%,金的浸出率为80.40%,与氢氧化钠浸出相比,硫酸浸出解离铁能有效提高金的浸出率。烟尘分别经过质量分数为15%硫酸浸出后氰化浸金,两次2 mol/L氢氧化钠浸出和氰化浸金后,烟尘中铁、砷和碳的总脱除率分别为33.65%、95.63%和79.60%,渣率为80.33%。此时,金的总浸出率为91.90%,氰化渣中金的含量为3.31g/t。与烟尘直接氰化浸出相比金的浸出率提高37.60%。     

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、Fe^3＋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1：5，浸出温度为35℃，硫脲质量浓度为10g／l，Fe^3＋抖质量分数为0．3％，浸出时间为1h，硫酸体积分数为5％。     

Cu2+及等离子电解氧化处理对Zr-4合金腐蚀性能的影响

采用电化学方法研究锆合金Zr-4在添加不同Cu2+浓度的0.5 mol/L NaCl溶液或0.5 mol/L Na2SO4中的腐蚀行为,探讨不同浓度Cu2+对Zr-4合金腐蚀性能的影响,同时,在10 g/L Na2SiO3.9H2O+10 g/L Na4P2O7.10H2O混合溶液中对Zr-4合金进行等离子电解氧化处理,并用极化曲线技术研究膜层的防护能力。结果表明:Cu2+能使Zr-4合金自腐蚀电位正移,降低极化曲线上钝化区的宽度,使得合金的抗孔蚀能力降低,腐蚀电流密度增加;在硫酸钠溶液中,Cu2+的添加没有使合金产生明显的孔蚀,这表明Zr-4合金的抗孔蚀能力下降是Cu2+和Cl共同作用的结果;等离子电解氧化处理能够大幅度提高Zr-4合金的抗孔蚀能力。     

Preparation of pure SbCl3 from lead anode slime bearing high antimony and low silver

A novel treatment process of lead anode slime bearing high antimony and low silver was developed by a potential-controlled chloridization leaching and continuous distillation.The experimental results show a high Sb 3+ concentration,489.2 g/L,in the leaching solution for two-stage countercurrent leaching process,and the leaching rates of Sb,Cu,Bi more than 99% when the potential is controlled at 450 mV.When the leaching solution is distillated and concentrated at 120°C,almost all the silicon compound is evaporated into the concentration distillate and exists as amorphous hydrated silica.By the continuous distillation,high pure SbCl3 could be prepared,and AsCl3 is enriched in the distillate while metals Bi,Cu are enriched in the continuous distillation residue.As a result,the recovery rate of Sb is more than 95%.     

Bio-oxidation of arsenopyrite

Oxidation of arsenopyrite with Acidithiobacillus ferrooxidans was studied. The electrochemical results show that arsenopyrite is firstly oxidized to As2S2 at the potential of 0.2-0.3 V （vs SHE） and As2S2 covers the electrode and retards the process continuously. While at higher potential over 0.3 V （vs SHE）, AszS2 is oxidized to H3AsO3, and H3AsO3 is then oxidized to H3AsO4 at 0.8 V （vs SHE）. The leaching results show that the addition of FeS2 can promote the oxidation of As^3＋ to As^5＋ and increase the activity of the bacteria. The best bio-oxidation technical parameters are the initial pH of 1.8-2.0, particle sizes less than 0.074 mm, temperature in the range of 25-30℃ and rotating speed of the orbital incubator of 100-160 r/min. The results provide theoretical and technological supports of bio-oxidation arsenopyrite for pretreating refractory arsenic gold ores.     

次氧化锌中砷的物相及砷的浸出(英文)

研究烟化炉次氧化锌中砷的物相类型。结果表明:按砷的物相可将次氧化锌分为3种类型。在一型次氧化锌中砷以As2O3形态存在,而在二型和三型次氧化锌中砷分别以亚砷酸锌(Zn(AsO2)2)和砷酸铅(Pb(As2O6),Pb4As2O9)形态存在。在热力学分析基础上,对二型次氧化锌进行浸出脱砷。结果表明:采用30g/LNaOH溶液,在液固比3、温度20°C的条件下,砷的浸出率在1h内可达到65%～70%,而铅、锌的损失均小于1%。     

Chemical behaviors of different arsenic-bearing sulphides bio-oxidated by thermophilic bacteria

1INTRODUCTION Arsenic bearinggoldoreiswidelydistributedinprovincesofYunnan,Guizhou,Sichuan,Guan gxi,Guangdong,Hunan,Jiangxi,Liaoning,Jilin,Hebei,Shanxi,Gansu,Qinghai,Xinjiang,etc.Withtheprocessdevelopmentofbacteriummetal lurgy[1,2],suchgoldoreresourcemaybereasona blyutilized,however,arsenicintheseoresishigh lytoxictotheleachingbacteriaandbecomesthe researchfocus.Arsenicisacomplexandvitalele mentofarsenic bearingmineralswiththeelectronconfigurationof4s34p3[3].WhenAslosesthree electro…     

Mechanism of influence of ferric ion on electrogenerative leaching of sulfide minerals with FeCl3

1 Introduction Electrogenerative leaching process is a newly- developed technique in hydrometallurgy. Although its principle has developed since the late 1960s[1], this technique has been overlooked in metallurgy until ZHANG et al[2] introduced it to the …     

Bioleaching of pyrite by A. ferrooxidans and L. ferriphilum

Pyrite oxidation rates were examined under various conditions in the presence of A.ferrooxidans and L.ferriphilum,in which different pulp concentration,inoculation amount,external addition of Fe3+ and initial pH value were performed.It is found that A.ferrooxidans and L.ferriphilum show similar behaviors in the bioleaching process.The increasing pulp concentration decreases the leaching rate of iron,and external addition of high concentration Fe3+ is also adverse to leaching pyrite.The increased inoculation amount and high initial pH value are beneficial to leaching pyrite,and these changed conditions bring more obvious effects on leaching pyrite by L.ferriphilum than by A.ferrooxidans.The results also show that adjusting the pH values in leaching process baffles leaching pyrite due to the formed jarosite.Jarosite formed in leaching process was observed using XRD,SEM and energy spectrum analysis,and a considerable amount of debris with a crystalline morphology is present on the surface of pyrite.The results imply that the indirect action is more important for bioleaching pyrite.     

Optimization of operating parameters and kinetics for chloride leaching of lead from melting furnace slag

The feasibility and kinetics of lead recovery from the slag of traditional lead melting furnace using chloride leaching were investigated. The effects of operating parameters such as leaching time, NaCl concentration, FeCl₃ concentration, liquid/solid ratio, stirring rate, temperature, and particle size on recovery of lead were studied and the optimization was done through the response surface methodology (RSM) based on central composite design (CCD) model. The optimum conditions were achieved as follows: leaching time 60 min, 80 °C, stirring rate 800 r/min, NaCl concentration 200 g/L, FeCl₃ concentration 80 g/L, liquid/solid ratio 16, and particle size less than 106 μm. More than 96% of lead was effectively recovered in optimum condition. Based on analysis of variance, the reaction temperature, liquid/solid ratio, and NaCl concentration were determined as the most effective parameters on leaching process, respectively. Kinetics study revealed that chloride leaching of galena is a first-order reaction and the diffusion through solid reaction product and chemical reaction control the mechanism. The activation energy of chloride leaching of galena was determined using Arrhenius model as 27.9 kJ/mol.     

Cu2+对钢铁磷化膜表面形貌的影响及其机理

采用扫描电镜和电化学工作站、盐雾实验研究了铜离子对钢铁磷化膜表面形貌、生成机制、防腐蚀性能的影响。结果表明:未加入铜离子时,磷化膜由片状的ZPO(Zn3(PO4)2.4H2O)组成;加入铜离子后,磷化膜由花瓣状的ZPO和团簇状的CuO组成。未加入铜离子时,磷化膜中ZPO的生成机制为由花瓣状至片状;加入铜离子后,磷化膜中ZPO的生成机制为由片状至花瓣状。铜离子对磷化膜的影响存在一个临界浓度6～8 g/L。在临界浓度下,随着磷化液中Cu2+的增多,磷化膜的耐腐蚀性能逐步提高;当磷化液中Cu2+的浓度超过临界浓度后,Cu2+会阻碍ZPO的形成,并且耐腐蚀性能下降。     

石煤钒矿硫酸活化常压浸出提钒工艺

研究石煤钒矿的硫酸活化提钒方法。分别考察矿石粒度、硫酸浓度、活化剂用量、催化剂用量、反应温度、反应时间和浸出液固比等因素对钒浸出率的影响。结果表明:石煤提钒的优化条件为矿石粒度小于74μm的占80%、硫酸浓度150 g/L、活化剂CaF2用量(相对于矿石)60 kg/t、催化剂R用量20 g/L、反应温度90℃、反应时间6 h、液固比(体积/质量,mL/g)2:1,在此优化条件下,钒浸出率可达94%以上;在优化条件下,采用两段逆流浸出,可有效减少活化剂CaF2以及浸出剂硫酸的消耗量;经过两段逆流浸出萃取反萃氧化水解工艺,全流程钒资源总回收率可达86.9%;V2O5产品纯度高于99.5%。     

湖南某高砷难处理金精矿的细菌氧化-氰化提金实验研究

湖南某高砷金精矿属于难处理矿石,含砷11.28%,含金66.18g/t,金的直接浸出率仅为21.91%.通过该样品5%、10%、15%、20%矿浆浓度的细菌氧化试验,发现金精矿砷的氧化率达到93%以上.细菌氧化渣的金浸出率随着矿浆浓度的增大而降低,5%矿浆浓度下细菌氧化渣的金浸出率为93.15%;10%矿浆浓度下细菌氧化渣的金浸出率为92.46%;15%矿浆浓度下细菌氧化渣的金浸出率为90.50%;20%矿浆浓度下细菌氧化渣的金浸出率为87.58%,比未经处理时金的直接氰化浸出率21.91%有了很大的提高,预处理效果很好.