CR法处理高砷高锑复杂锡烟尘

用 CR 法处理高砷高锑复杂锡烟尘的关键步骤是 CR 蒸砷过程,即用一种中浓度盐酸浸出锡烟尘,同时用一种金属或金属硫化物作为还原剂还原高价砷和锑,并蒸馏出二氯化砷。接着用硫化法沉淀砷、再生盐酸和消除砷害。CR 法的突出特点是将铅、砷、锌等杂质元素一次性彻底脱除,有利于伴生元素的回收和消除砷害。     

采用复合盐沉淀法从含砷废水中回收三氧化二砷及复合盐的循环利用

采用复合盐沉淀法处理含砷废水,研究了钙砷比、铜砷比、铁砷比、锌砷比对砷脱除率的影响,并以硫酸浓度、液固比、浸出时间、浸出温度为考察因素,对含砷沉淀渣进行浸出,从浸出液中回收三氧化二砷,同时回用脱砷后母液。结果表明:在n(Ca)/n(As)=1.05、n(Cu)/n(As)=0.45、n(Fe)/n(As)=1.20、n(Zn)/n(As)=1.20的复合盐配比下,处理初始As(Ⅲ)浓度为0.05～9.76 g/L含砷废水时,砷残留浓度均低于14 mg/L,通过增加复合盐用量进行二次脱砷沉淀,滤液中铜、锌、砷浓度在《污水综合排放标准》(GB8978—1996)范围内。在液固比(mL:g)为3:1、浸出时间为0.5 h、浸出温度为25℃、硫酸浓度0.87 mol/L条件下对含砷渣进行浸出,并回收三氧化二砷,可使砷回收率达到72.38%。将回收后母液回用处理初始As(Ⅲ)浓度为50mg/L的含砷废水,可使砷脱除率达83.65%,复合盐利用率可达80%以上,具有生态与经济双重效益。     

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。     

硫酸溶液硫化沉砷过程及磁场对沉砷的影响

由硫酸溶液硫化沉砷过程中氧化还原电势的变化，讨论硫化沉砷过程，同时研究磁场效应对沉砷过程电势变化及溶液含砷的影响，认为磁场效应在一定条件下有益于提高砷的沉降速度和净化程度。     

不同喷吹气体对铜冶炼熔渣中砷气化脱除的影响（英文）

为了减少铜熔炼渣中砷所带来的环境问题，提出一种基于气体喷吹脱除熔融铜渣中砷的方法，期望在铜回收工艺前将铜熔炼渣中的砷尽可能以粉尘的形式富集。对比惰性气体、氧化性气体和还原性气体对熔渣中砷脱除的影响。氧化性气体CO₂氧化夹杂冰铜中的砷及砷硫化物，并充当气体载体将砷氧化物带出熔池。还原性气体CO可以将FeO_x-SiO₂熔渣中的砷氧化物还原，并使其挥发至气相，可以实现60%以上的砷脱除率。该研究为熔炼渣中砷脱除提供指导。     

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。     

含砷钴镍渣中砷提取与砷盐制备的资源化利用(英文)

对某厂硫酸锌溶液砷盐净化工艺产生的含砷钴镍渣进行砷提取与资源化利用研究。基于含砷钴镍渣中砷的存在形态并利用砷的两性特性,考察碱介质氧压浸出砷的方法,确定并优化氧气气氛下碱介质浸出砷的最佳条件。结果表明,在溶出温度140℃、碱介质NaOH浓度150 g/L、氧压0.5 MPa、液固比5∶1的条件下,砷的浸出率达到99.14%。根据As_2O_5、ZnO和PbO在NaOH溶液中的溶解特性,提出采用富砷浸出液直接冷却结晶分离获得砷酸钠晶体的砷分离-碱介质循环的方法,且富砷浸出液直接在25℃下的结晶率达88.9%;根据氧化还原电位,将砷酸钠晶体溶解获得的溶液直接采用SO_2气体进行还原来制备三价砷盐,在一定条件下砷的还原率达92%,从还原液可制得正八面体结构的As_2O_3晶体循环或将还原液直接循环回用于硫酸锌溶液砷盐的净化系统。利用含砷钴镍渣中砷的氧压碱介质浸出-浸出液冷却结晶—砷酸钠溶液SO_2气体还原-As_2O_3晶体制备的技术路线可实现含砷钴镍渣中砷的提取与资源化利用。     

细菌氧化预处理含砷难处理金矿的研究进展

含砷难处理硫化矿经过细菌预氧化,将包裹Au的硫化矿物毒砂、黄铁矿等溶解、破坏,将Au暴露出来,可大大提高后续氰化浸出中Au的回收率。细菌氧化技术具有投入低、工艺简单、污染轻或无污染等优点。作者在回顾细菌浸矿发展历史与现状的基础上,着重阐述了含砷难处理金矿细菌氧化预处理的机理、氧化菌种和工艺流程,并提出了该技术现存的一些亟待解决的问题。     

不锈钢冶炼渣熔融还原及毒性浸出实验研究

通过半工业化试验证实了可以通过铁浴熔融还原工艺快速回收不锈钢冶炼渣中的铬。采用X射线衍射分析、荧光分析和化学分析方法,得到不锈钢渣的初始成分及物相,熔融还原处理后熔渣中Cr最优收得率达到98.6%,渣中残铬量最低可降至0.063%。并根据相关标准进行了毒性浸出试验,确认了不锈钢冶炼渣经过处理,浸出毒性从0.62 mg/L降低至0.017 86 mg/L,远远低于一般废弃物的标准。     

含砷石灰铁盐渣的理化特性及其浸出行为（英文）

以典型石灰铁盐法处理二种含砷废水产生的污泥(污酸渣和砷酸钙渣)为研究对象,采用ICP-AES、SEM-EDS、XRD、XPS和化学物相分析等检测手段对其化学组成、形貌特征、物相结构及砷的赋存状态进行研究,采用毒性浸出实验和BCR三步连续提取法考察污泥中砷的浸出行为。研究结果表明,污酸渣和砷酸钙渣中砷的含量分别为2.5%和21.2%,主要组成物相为砷酸盐及砷氧化物,均以无定型的颗粒均匀分散或团聚在污泥中。砷的浸出毒性超出TCLP标准规定限值的119和1063倍,浸出率分别为47.66%和50.15%。砷以酸可提取态和可还原态为主,两者共占90%左右,而稳定的残渣态含量相对较低,这是含砷石灰铁盐渣浸出毒性大、环境活性高的直接原因。本研究为含砷石灰铁盐渣无害化处理技术提供了大量有用的基本数据。     

Process and mechanism of hydrothermal stabilization for arsenic sulfide sludge containing elemental sulfur

An optimized hydrothermal treatment was employed to stabilize the arsenic sulfide sludge (ASS). Under the optimal conditions (160 °C, 2 h, liquid-to-solid (L/S) ratio of 1:1, and initial pH of 2), the leaching concentrations of As and Cd decreased from 504.0 and 12.0 mg/L to 1.23 and 0.03 mg/L of the treated ASS, respectively. The results indicate that the stabilization of the ASS was achieved through structure transformation from the particles into a bulk and the speciation transformation of As and Cd. Besides, sulfur in the ASS could significantly improve the stabilization property due to its melting and polymerization.     

Extraction of arsenic from arsenic-containing cobalt and nickel slag and preparation of arsenic-bearing compounds

The arsenic extraction from the arsenic-containing cobalt and nickel slag, which came from the purification process of zinc sulfate solution in a zinc smelting factory, was investigated. The alkaline leaching method was proposed according to the mode of occurrence of arsenic in the slag and its amphoteric characteristic. The leaching experiments were conducted in the alkaline aqueous medium, with bubbling of oxygen into the solution, and the optimal conditions for leaching arsenic were determined. The results showed that the extraction rate of arsenic was maximized at 99.10% under the optimal conditions of temperature 140 °C, NaOH concentration 150 g/L, oxygen partial pressure 0.5 MPa, and a liquid-to-solid ratio 5:1. Based on the solubilities of As₂O₅, ZnO and PbO in NaOH solution at 25 °C, a method for the separation of As in the form of sodium arsenate salt from the arsenic-rich leachate via cooling crystallization was established, and the reaction medium could be fully recycled. The crystallization rate was confirmed to reach 88.9% (calculated on the basis of Na₃AsO₄) upon a direct cooling of the hot leachate down to room temperature. On the basis of redox potentials, the sodium arsenate solution could be further reduced by sulfur dioxide (SO₂) gas to arsenite, at a reduction yield of 92% under the suitable conditions. Arsenic trioxide with regular octahedron shape could be prepared successfully from the reduced solution, and further recycled to the purification process to purify the zinc sulfate solution. Also, sodium arsenite solution obtained after the reduction of arsenate could be directly used to purify the zinc sulfate solution. Therefore, the technical scheme of alkaline leaching with pressured oxygen, cooling crystallization, arsenate reduction by SO₂ gas, and arsenic trioxide preparation, provides an attractive approach to realize the resource utilization of arsenic-containing cobalt and nickel slag.     

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%。     

超声强化单斜磁黄铁矿从铜烟灰中选择性硫化沉淀铜离子

在单斜磁黄铁矿(MPr)处理废水重金属离子过程中表面产生的硫化物钝化膜严重阻碍进一步反应.采用超声波技术辅助MPr回收铜离子.XPS分析结果表明,反应过程中MPr表面存在CuS产物.XRD和SEM分析结果表明,在超声条件下颗粒表面的CuS被剥离.动力学结果表明,常规和超声条件下的反应均符合Avrami模型.在超声条件下...     

Cascade sulfidation and separation of copper and arsenic from acidic wastewater via gas-liquid reaction

Copper and arsenic in acidic wastewater were separated by cascade sulfidation followed by replacement of arsenic in the precipitates by copper in the solution which was realized by recycling precipitates obtained in the first stage into the initial solution. The effects of reaction time, temperature and H₂S dosage on copper and arsenic removal efficiencies as well as the effects of solid-to-liquid ratio, time and temperature on the replacement of arsenic by copper were investigated. With 20 mmol/L H₂S at 50 °C within 0.5 min, more than 80% copper and nearly 20% arsenic were precipitated. The separation efficiencies of copper and arsenic were higher than 99% by the replacement reaction between arsenic and copper ions when solid-to-liquid ratio was more than 10% at 20 °C within 10 min. CuS was the main phases in precipitate in which copper content was 63.38% in mass fraction.     

铜闪速熔炼渣中砷的赋存状态和浸出毒性（英文）

铜冶炼含砷炉渣的高效安全处置取决于对其含砷物相及其浸出毒性的准确认识。采用X射线荧光光谱、X射线衍射、电子探针显微分析、扫描电子显微术和选择性逐级提取法对铜熔炼渣中的含砷物相进行鉴定,并基于对炉渣中不同含砷物相的选择性逐级提取结果探讨渣中砷浸出毒性的可能来源。结果表明,砷以水溶性砷、铜砷金属间化合物、铜砷硫化物以及固化在铁橄榄石和硅酸盐玻璃相中的砷等形式赋存在熔炼渣中。浮选过程可以去除熔炼渣中的水溶性砷并回收铜砷金属间化合物,降低渣尾矿的砷浸出毒性,使其符合USEPA和SEPA标准要求。     

Selective leaching of arsenic from copper converter flue dust by Na2S and its stabilization with Fe2(SO4)3

The alkaline leaching of arsenic (As₂O₃) by Na₂S, together with its precipitation by Fe₂(SO₄)₃ was studied. Response surface methodology based on central composite design was employed to quantify and qualify the effect of pertinent factors and to develop statistical models for optimization purposes. Based on the obtained results, 89% of arsenic is removed from the dust under following optimum predicted conditions: Na₂S concentration of 100 g/L and solid to liquid ratio of 0.163 g/mL at 80 °C. It is found that solid to liquid ratio and Na₂S concentration are the significant factors influencing the leaching process. In the precipitation process, more than 99.93% of arsenic from the leaching solution is removed in the form of amorphous ferric arsenate, at pH 4.8 when Fe³⁺ to arsenic and H₂O₂ to arsenic molar ratios are set at 5:1 and 4:1, respectively. Also, Fe³⁺ to arsenic ratio and pH are the most significant factors, and the interaction between these terms is significant.     

An alternative to arsenic disposal: Wood preservation

Arsenic serves as a key active ingredient for preserving wood from attack by fungus and other wood-destroying microorganisms. The use of arsenic trioxide in water-borne preservative systems such as chromated copper arsenate provides a major market for arsenic-trioxide production from the nonferrous roasting and smelting industry. For more information, contact R.M. Leach, Osmose, 980 Ellicott Street, Buffalo, New York 14209; fax (716) 882-2834.