砷酸铜制备工艺过程热力学分析

绘制了Cu-As-H2O系电位－pH图、不同As浓度下lg[Cu]T[As]T)-pH图以及Fe-As(V)-H2O系lg[Fe]T-pH图等,分析了由墨铜渣制备胂酸铜过程的热力学。酸性氧化浸出可同时浸出Cu和As,pH＝2左右脱脱铁率可达99％以上。铜砷比和pH值的不同,可以得到不同形式的砷酸铜;CuHAsO4,Cu2AsO4OH,Cu5H2(AsO4)。在胂酸铜制备工艺条件下,所得砷酸铜分子式为Cu5H2(AsO4)4。热力学分析结果与XRD相一致。     

硫化物矿床氧化带砷酸盐矿物的地质找矿意义

砷酸盐矿物是主要产出于硫化物矿床氧化带中的次生矿物,在自然界中已发现２５０ 多种,我国目前仅发现该类矿物３８ 种。砷酸盐矿物的生成与原生矿石的矿物成分及其数量、气候条件和介质条件等因素密切相关。毒砂及含砷矿物和黄铜矿、黄铁矿、磁黄铁矿、方铅矿、闪锌矿等硫化物的大量存在是形成砷酸盐矿物的物质基础。该类矿物一般多形成于温湿多雨的热带－ 亚热带气候区域和矿床围岩为碳酸盐岩的弱酸性－ 中性的介质环境中。砷酸盐矿物常是硫化物矿床氧化带发育至末期阶段的重要产物之一,对判断原生矿床的氧化程度和剥蚀深度有一定的指示意义;根据砷酸盐矿物的组合类型可较快速地确定原生矿床（ 体） 的工业类型和找矿方向。根据砷酸盐矿物的形成条件,砷酸盐矿物大量发育的铁帽氧化带一般可作为寻找（ 夕卡岩型） 铜锡多金属硫化物矿床的重要标志。     

砷酸钠混合盐微波环保型干燥工艺探讨

研究了用微波干燥砷酸钠混合盐的过程。研究表明:采用微波干燥砷酸钠混合盐,克服了传统干燥中的"冷中心"现象。与传统干燥相比,微波干燥砷酸钠混合盐的能耗大幅降低、干燥能力大幅提高,同时,干燥过程不扬尘,属节能、环保型干燥,从根本上解决目前砷碱渣综合回收的瓶颈问题。     

Formation of metal agglomerates during carbonisation of chromated copper arsenate (CCA) treated wood waste: Comparison between a lab scale and an industrial plant

This paper compares the results obtained by scanning electron microscopy coupled to X-ray analysis (SEM-EDXA) of the solid product after carbonisation of treated wood waste in a lab scale and in an industrial installation. These setups (lab scale and industrial) are characterized by different operating conditions of the carbonisation process. Moreover, the wood waste input to the processes differs significantly. From this study, it is clear that some similarities but also some differences exist between the lab scale study and the study with the industrial Chartherm plant. In both reactors, a metal (and mineral) agglomeration process takes place, even in the case of untreated wood. The agglomerates initially present in the wood input may serve as a seed for the metal agglomeration process during "chartherisation". The industrial setup leads to a broader range of agglomerates' size (0.1-50 microm) and composition (all possible combinations of Cu, Cr, As and wood minerals). Some agglomerates contain the three metals but the major part is a combination of wood minerals and one or two of the three preservative metals, while all agglomerates analysed in the lab scale product contain the three metals. The separate influence of wood input characteristics and process conditions cannot be derived from these experiments, but the observations suggest that the higher the CCA retention in the wood input is, the easier is the metal agglomeration process during chartherisation of CCA treated wood waste. From the analyses performed in this study it seems that copper behaves differently in the sense that it agglomerates easily, but the resulting particles are small (<1 microm).     

柱撑蒙脱石对水中砷(Ⅴ)的吸附研究

采用羟基聚合Al-Fe为柱化剂对蒙脱石进行改性,将制得的柱撑蒙脱石作为吸附剂,研究了其对水溶液中砷的去除效果及其影响因素.结果表明:对蒙脱石柱撑改性后能显著提高其吸附性能.平衡吸附量与平衡质量浓度之间的关系符合Freundlich和Langmuir等温吸附方程所描述的规律.用Elovich方程和双常数方程可以较好地拟合柱撑蒙脱石对As(Ⅴ)的动力学吸附过程.     

砷铁渣中砷酸铁的热力学分析及热分解试验

利用铁盐法处理某铅冶炼工业含砷废水,得到砷质量分数为10%的砷铁渣,物相分析表明砷与铁在渣中以砷酸铁的形态存在。据热力学分析,砷酸铁化合物在1600℃以下不会热分解,表明其热力学性质稳定;而在有添加剂碳的情况下,砷酸铁的热分解温度大大降低。试验结果表明:在1200℃条件下,静态焙烧5h,砷酸铁砷的挥发率在90%以上,铁富集10%以上。     

Shewanella sp. O23S as a Driving Agent of a System Utilizing Dissimilatory Arsenate-Reducing Bacteria Responsible for Self-Cleaning of Water Contaminated with Arsenic

The purpose of this study was a detailed characterization of Shewanella sp. O23S, a strain involved in arsenic transformation in ancient gold mine waters contaminated with arsenic and other heavy metals. Physiological analysis of Shewanella sp. O23S showed that it is a facultative anaerobe, capable of growth using arsenate, thiosulfate, nitrate, iron or manganite as a terminal electron acceptor, and lactate or citrate as an electron donor. The strain can grow under anaerobic conditions and utilize arsenate in the respiratory process in a broad range of temperatures (10–37 °C), pH (4–8), salinity (0%–2%), and the presence of heavy metals (Cd, Co, Cr, Cu, Mn, Mo, Se, V and Zn). Under reductive conditions this strain can simultaneously use arsenate and thiosulfate as electron acceptors and produce yellow arsenic (III) sulfide (As₂S₃) precipitate. Simulation of As-removal from water containing arsenate (2.5 mM) and thiosulfate (5 mM) showed 82.5% efficiency after 21 days of incubation at room temperature. Based on the obtained results, we have proposed a model of a microbially mediated system for self-cleaning of mine waters contaminated with arsenic, in which Shewanella sp. O23S is the main driving agent.     

铁铝复合氧化物吸附砷氟性能实验研究

采用共沉淀法制备了复合铁铝氧化物吸附剂,并对其表面ξ电位和砷氟共存时除砷氟性能进行了初步研究。ξ电位表明铁铝复合氧化物pHzpc在9.0附近;铁铝复合氧化物对砷氟共存溶液中As(V)和F-均表现出很强的吸附能力,决定F-的去除率的是铝含量;该吸附剂对砷氟共存溶液As(V)在广谱pH范围内具有很高的去除能力,对F-在pH为6~7之间时去除率最高;砷氟共存溶液中As(V)对F-具有竞争吸附作用。     

镁铝阴离子粘土对砷酸根离子的吸附作用

利用共沉淀水热法制备了镁铝阴离子粘土材料，研究了其水溶液对砷酸根离子的去除能力。结果表明：镁铝阴离子粘土对砷酸根离子具有较高的去除率和吸附容量、较快的吸附速度。砷酸根离子的吸附平衡数据很好的符合Freundlich型吸附等温方程。同时，吸附动力学数据完全符合Lagergren二级速度方程。吸附砷酸根离子后的阴离子粘土材料，用稀NazCO3溶液可以很好的洗脱再生。阴离子粘土对砷酸根离子的吸附属于层间离子交换作用。