二段脱铜液还原结晶法脱砷新工艺

对铜电解液脱砷方法进行研究,提出以二段脱铜液为原料,采用SO2还原结晶法脱砷新工艺。在二段脱铜液中通入SO2,将其中的As(Ⅴ)还原成As(Ⅲ),还原后的溶液通过蒸发结晶析出As2O3,达到二段脱铜液脱砷的目的。结果表明:当As(Ⅴ)浓度为12.41 g/L、H2SO4浓度为253.00 g/L、反应温度为60℃时,向二段脱铜液中通入SO290 min后静置90 min,二段脱铜液中As(Ⅴ)的还原率达到94.54%。还原后的溶液进行蒸发结晶,当蒸发前与结晶后的体积比(V0:V1)为3.5时,砷的脱除率达到91.33%,结晶产物为As2O3。与传统脱砷工艺相比,新工艺具有操作简单、成本低廉及砷的脱除效果明显等优势。     

水合肼对铜电解液净化的作用

在铜电解液中加入水合肼产生沉淀,使铜电解液中砷、锑、铋杂质得到有效去除。当电解液Cu2+质量浓度为22g/L,硫酸质量浓度为203g/L,反应温度为42℃,反应时间为60mi,n砷、锑、铋质量浓度分别为8.80 g/L、0.36 g/L、0.20 g/L时,按照铜电解液与水合肼体积比为20:1在铜电解液加入水合肼,铜脱除率为97.04%,砷、锑、铋去除率分别为5.28%、37.92%、94.40%。在卤化物作用下,有助电解液中砷的去除。杂质的脱除有一定影响。在铜电解液中加入水合肼产生沉淀有Cu4SO4（OH）6·H2O、Cu2（OH）3NO3、Cu3（AsO4）（OH）3等。     

铜电解液净化中铜砷的分离与回收(英文)

经二氧化硫还原、蒸发结晶,使铜电解液中铜、砷、锑和铋得到有效去除。结晶产物经过溶解、氧化、中和、沉淀、过滤和蒸发结晶,得到三氧化二砷和硫酸铜。当采用SO2将铜电解液中As(Ⅴ)充分还原为As(Ⅲ),并加热蒸发浓缩铜电解液中硫酸浓度至645g/L时,铜电解液中铜、砷、锑和铋的去除率分别为87.1 %,83.9 %,21.0 %和84.7%。在温度30℃,将65g结晶产物溶于200mL自来水时,砷的去除率为92.81%。将所得滤液在如下条件下净化:n(Fe):n(As)为1.2,双氧水为理论用量的19倍,氧化温度为45℃,氧化时间为40min,终点pH为3.7,净化后蒸发浓缩结晶,所得硫酸铜溶液中硫酸铜含量达到98.8%。     

五价锑在脱除铜电解液中砷、锑、铋杂质中的作用(英文)

通过向含有45 g/L Cu2+、185 g/L H2SO4、10 g/L As和0.5 g/L Bi的铜电解液中加入Sb(V),研究五价锑对铜电解液中砷、锑、铋杂质脱除作用机理。过滤电解液,采用化学分析、SEM、TEM、EDS、XRD、FTIR等方法对沉淀渣的结构形貌和成分进行表征。结果表明,沉淀渣呈尺寸为50~200μm的不规则块状,其化学成分主要为砷、锑、铋和氧。红外光谱检测表明,沉淀渣主要特征官能团为As—O—As、As—O—Sb、Sb—O—Bi、Sb—O—Sb和Bi—O—Bi。X射线衍射和电子衍射检测结果表明,沉淀渣由AsSbO4、BiSbO4和Bi3SbO7组成。锑酸盐的生成是五价锑脱除铜电解液中砷、锑、铋杂质的主要原因。     

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。     

SO_2还原沉金后液回收硒碲及捕集铂钯

以沉金后液为原料,通过SO2直接还原回收硒碲和捕集铂钯。采用X射线衍射仪(XRD)和扫描电镜(SEM)对还原产物的物相、微观形貌进行表征,结果表明:当反应温度为85℃,SO2流量为0.2 L/min,反应时间为4 h,H+浓度为3.3 mol/L和Cl?浓度为0.72 mol/L时,Se和Te回收率分别为99.5%和96.64%,Pt和Pd回收率均达到了100%,所得黑色还原产物中硒、碲、铂和钯的质量分数分别为28.06%、52.3%、0.084%和0.588%。产物中硒和碲均以单质态形式存在,其形貌为球状体和柱状体。     

锌冶炼中浸渣锌还原浸出机制与动力学

以锌冶炼中浸渣为研究对象,研究中浸渣的化学成分及锌的存在形态,锌主要以铁酸锌形式存在。采用SO2做还原剂,研究温度、初始硫酸浓度、二氧化硫分压对锌浸出效率的影响,并分析中浸渣中锌还原浸出反应机制及动力学。结果表明:H+在锌还原浸出过程中起关键作用,锌还原浸出反应活化能为31.67 k J/mol,为化学反应控制;SO2做还原剂时,反应时间、液固比及初始酸度均大幅降低。反应最佳工艺条件:初始硫酸浓度80 g/L、温度95℃、液固比(L/S)10 m L/g、二氧化硫分压200 k Pa、反应时间120 min。该工艺条件下,中浸渣中锌浸出率达99%以上。XRD和ICP分析表明:中浸渣中铁酸锌分解,硫化锌在该反应条件下未完全浸出,还原浸出渣中主要化学成分为铅和锌,主要物相为Pb SO4和Zn S。     

从硫酸溶液中还原制取金属碲粉

采用SO2作还原剂从含碲的硫酸溶液中制取碲粉,并确定了SO2从硫酸溶液中还原碲的最佳条件:反应温度80℃,NaCl浓度1.2 mol/L,SO2流量0.1 m3/h,反应时间40 min,碲的还原率达到99.63%。还原所得粗碲粉经亚硫酸钠脱硒,盐酸酸洗除杂处理,硒、砷、锡、铜的脱出率分别达到99%、93%、80%、87.5%,得到含碲99.669%的金属碲粉。XRD和SEM表征表明还原碲粉的形态为针状晶体。     

Te(Ⅳ)-H2SO4-H2O体系中卤素离子催化还原Te(Ⅳ)反应动力学

以卤素离子(Cl-、Br-、I-)为催化剂,对SO2还原Te(Ⅳ)反应动力学进行研究.结果表明:在高浓度硫酸体系中,卤素离子(Cl-、Br-、I-)的浓度为0.3 mol/L,SO2流量为18 L/h,温度为90 ℃,Cl-、Br-和I-的反应时间分别超过60、10、10 min时,Te(Ⅳ)还原率均为97%.以Cl-和Br-为催化剂时,还原产物为单质碲;I-为催化剂时,还原产物为TeI.Cl-催化还原Te(Ⅳ)动力学表明,反应速率与Te(Ⅳ)浓度的成正比,该化学反应属于准一级反应.反应活化能受Cl-浓度的影响,当Cl-浓度为0.1和0.3 mol/L时,其活化能分别为44.871和36.714 kJ/mol.     

高砷铜电解液中旋流电积脱杂

针对高砷铜电解液中砷、锑、铋等杂质含量高,铜含量低的特点,采用旋流电积技术对其进行电积脱杂。考察电流密度、循环流量和铜离子含量对砷、锑、铋等杂质脱除率的影响。4 L小试结果表明:在电流密度500 A/m~2、循环流量250 L/h,铜离子浓度1~3 g/L的条件下,砷、锑和铋的脱除率分别达90.56%、98.90%、99.99%,电积产物黑铜渣中铜-砷比低至0.50。600 L扩试结果表明:在电流密度800 A/m~2、循环流量6000 L/h,铜离子浓度0.5~3 g/L的条件下,砷、锑和铋的脱除率分别达89.30%、80.00%、99.99%。采用旋流电积技术进行电积脱杂可以有效降低铜的损失,避免砷化氢气体的产生,脱杂效果明显。     

铜基银枝晶的制备和氧还原电催化性能

通过迦尔瓦尼置换反应在不同的Ag+溶液中制备出了铜基银枝晶,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和电化学工作站分别对样品的结构、微观形貌以及电化学性能进行了表征。结果表明,随着溶液中Ag+浓度和反应时间的增加,银的形貌从团簇状向树枝状转变,氧还原电催化性能也增强;在相同浓度Ag+溶液中,SO42-比NO3-更能促进枝晶的生长,但当阴离子是NO3-时比阴离子是SO42-时所制备的银枝晶的氧还原电催化性能更好;在10 mmol/L AgNO3溶液中,反应时间为1800 s时制备的银枝晶电极使H2O2的还原峰电流最大,在0.1 mol/L Na2SO4+5mmol/L H2O2溶液中,恒电位为-0.32 V时,其稳态电流密度可达2.83 mA/cm2。初步提出了银枝晶的生长机制和H2O2的氧还原催化机制。     

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...     

铅阳极泥脱砷预处理研究

采用氢氧化钠溶液循环浸出法对铅阳极泥进行预脱砷,考察了液固比、氢氧化钠浓度、浸出温度和浸出时间对脱砷效果的影响;在液固比10∶1、氢氧化钠浓度2.5 mol/L、浸出温度80℃、浸出时间8 h的条件下,砷的浸出率可达94%以上;含砷浸出液经硫化钠沉砷后可返回浸出工序循环使用,硫化钠与砷质量比为3∶1时,沉砷率可达88%以上,同时回用浸出工序后,砷浸出率达94%以上,浸出液循环使用对脱砷没有影响。     

电解锌的SO2阳极反应动力学

研究了湿法炼锌电解过程中,用SO2在阳极放电代替传统的水分解放电而降低槽电压,以达到节能的目的。使用铂作阳极,在电解液中通入SO2进行电解,节能可达40％。通过SO2阳极极化曲线的测定,考察了SO2浓度、H2SO4浓度、温度和搅拌速度对阳极反应速率的影响。研究表明：在铂阳极上SO2阳极反应符合电化学控制,遵从塔菲尔公式;SO2的反应级数为3．3,表现活化能为31．8kJ/mol,硫酸的反应级数为零。     

Separation of arsenic and antimony from dust with high content of arsenic by a selective sulfidation roasting process using sulfur

The separation of arsenic and antimony from dust with high content of arsenic was conducted via a selective sulfidation roasting process. The factors such as roasting temperature, roasting time, sulfur content and nitrogen flow rate were investigated using XRD, EPMA and SEM–EDS. In a certain range, the sulfur addition has an active effect on the arsenic volatilization because the solid solution phase ((Sb,As)₂O₃) in the dust can be destroyed after the Sb component in it being vulcanized to Sb₂S₃ and this generated As₂O₃ continues to volatile. In addition, an amorphization reaction between As₂O₃ and Sb₂O₃ is hindered through the sulfidation of Sb₂O₃, which is also beneficial to increasing arsenic volatilization rate. The results show that volatilization rates of arsenic and antimony reach 95.36% and only 9.07%, respectively, under the optimum condition of roasting temperature of 350 °C, roasting time of 90 min, sulfur content of 22% and N₂ flow rate of 70 mL/min. In addition, the antimony in the residues can be reclaimed through a reverberatory process.     

电解锌的SO_2阳极反应动力学

研究了湿法炼锌电解过程中 ,用SO2 在阳极放电代替传统的水分解放电而降低槽电压 ,以达到节能的目的。使用铂作阳极 ,在电解液中通入SO2 进行电解 ,节能可达 40 %。通过SO2 阳极极化曲线的测定 ,考察了SO2 浓度、H2 SO4 浓度、温度和搅拌速度对阳极反应速率的影响。研究表明 :在铂阳极上SO2 阳极反应符合电化学控制 ,遵从塔菲尔公式 ;SO2 的反应级数为 3.3,表观活化能为 31.8kJ/mol,硫酸的反应级数为零     

Novel technology of purification of copper electrolyte

The effects of arsenic with different valence states on the purification of copper electrolyte were studied and a novel technology of purification of copper electrolyte by copper arsenite was proposed. The results show that the purification performance of As（Ⅲ） compounds is better than that of As（Ⅴ） compounds. The purification technology by copper arsenite has the advantages of simple operation, high purification performance and low cost in comparison with other technologies and its appropriate purification conditions are that copper arsenite concentration is 18 g/L, reaction temperature is 65 ℃ and reaction time is 8 h. The removal rates of Sb and Bi are 53.22% and 58.67% respectively under these conditions. The purification principle show that a kind of yellow precipitate mainly composed of arsenic, antimony （ Ⅴ ）, bismuth and oxygen forms in electrolyte after copper arsenite is added, and consequently antimony and bismuth are removed from electrolyte.     

Preparation of copper arsenite and its application in purification of copper electrolyte

The preparation of copper arsenite with arsenic trioxide was presented and its application in the purification of copper electrolyte was proposed. The variables of n（OH^-）/n（As）, n（Cu）/n（As）, NaOH concentration, reaction temperature and pH value have some effects on the yield of copper arsenite. The optimum conditions of preparing copper arsenite are that the molar ratio of alkali to arsenic is 2：1, NaOH concentration is 1 mol/L, the molar ratio of copper to arsenic is 2：1, pH value is 6.0 and reaction temperature is 20℃. The yield of copper arsenite is as high as 98.65% under optimum conditions and the molar ratio of Cu to As in the product is about 5：4. The results of the purification experiments show that the removal rate of antimony and bismuth is 53.85% and 53.33% respectively after 20g/L copper arsenite is added. The purification of copper electrolyte with copper arsenite has the advantages of simple technique, good purification performance and low cost.