Bioleaching of refractory gold ore （ Ⅲ ）——Fluid leaching Jinya refractory gold concentrate by Thiobacillus ferrooxidans

A novel fluidized-bed reactor was designed and installed for bloleaching in a semi-continuous way, by which a process for biuleaching-cyanidation of Jinya refractory gold arsenical concentrate was studied. The arsenic extraction rate reaches 82.5 % after 4-day batch biooxidation of the concentrate under the optimized condition of pH 2.0, ferric ion concentration 6.Sg/L and pulp concentration 10%. And leached rate of gold in the following cyanida.tion is over 90%. The parameters of three series fluidized-bed reactors exhibit stability during the semi-continuous bioleaching of the concentrate.Armmic in the concentrate can be got rid of 91% after 6-day leaching. Even after 4 days, 82% of arsenic extraction rate was still obtained. The recovery rates of gold are 92 % and 87.5 % respectively in cyaniding the above bioleached residues.The results will provide a base for further commercial production of gold development.     

金盾供水

<正>开封金盾压力容器设备有限公司地处历史文化名城,七朝古都开封市所辖的开封黄龙产业集聚区;西距市区中心仅10公里。公司北临陇海铁路,距途经开封的四条高速公路入口处仅7公里,地理位置优越,交通便利。我公司成立以来全力打造净化无塔供水、一体化净水设备、除铁、除锰、除氟、除砷、各种大型水处理工程设计、制造、施工、安装、民用无塔供水、高层无负压供水设备、移动净水设备、校园直饮水设备、简易应急供水设备。公司十年在水处理行业取得五项专利。金盾产品具有技术含量高、质量稳定等优点。我公司拥有一批专职高级     

黄河内蒙古段干流沉积物中砷含量及形态研究

为探明黄河内蒙古段沉积物中砷含量及形态分布特征,采集黄河内蒙古段干流柱状沉积物,采用HNO4-H2SO4-HCl O4法消解沉积物样品,提取沉积物中吸附型砷(A-As)、铝型砷(Al-As)、铁型砷(Fe-As)、钙型砷(CaAs)、包蔽型砷(O-As)5种形态砷,并采用氢化物发生原子荧光分光光度法测定砷含量。结果表明:黄河内蒙古段干流柱状沉积物中砷含量为7.123~16.661 mg/kg,平均为9.292 mg/kg;从整体上看,左岸沉积物砷含量高于右岸,随深度增加砷含量呈下降趋势,从上游至下游砷含量在黑柳子段出现高值;黄河内蒙古段沉积物中砷以Ca-As为主,O-As次之;随着深度的增加,总体上,Ca-As含量略有升高,A-As和O-As含量有所下降,Al-As和Fe-As含量基本不变。     

库仑滴定法测定工业废水中微量砷

以库仑滴定法测定工业废水中微量砷，以死停终点法确定滴定终点，最后以EXCEL处理实验数据，本方法具有灵敏度高，准确，简便快速，仪器便宜，易于推广的特点，特别适用于工厂及县级以下环境监测站进行水中微量砷的检测，方法的回收率为99．3％。     

常规火焰原子吸收光谱法测定水中的痕量砷

利用砷、镉在 2 2 8.8nm波长处重叠谱线的光谱干扰效应 ,研究了砷、镉共存体系的干扰特点 ,采用均匀设计 ,数学方法和计算机技术进行数据处理 ,实现了用常规火焰原子吸收光谱法同时测定痕量砷和镉 ,其中测定砷的灵敏度可达 10ng/ml,利用该方法分析了水中的痕量砷 ,其结果令人满意。     

砷对人体的危害与防治

砷是一个广泛存在并且具有准金属特性的元素 ,呈灰色斜方六面体结晶 ,有金属光泽 ,不溶于水 ,极易氧化 ,砷和砷的化合物一般都有毒 ,尤以三氧化二砷 (俗称信石 ,砒霜等 )的毒性最为剧烈 ,是一种白色粉状或块状物 ,无臭、无味。1　砷的毒性砷的毒性与它的化学性质和价态有关。单质砷因不溶于水 ,摄入有机体后几乎不被吸收而完全排出 ,一般无害 ;有机砷 ,除砷化氢的衍生物外 ,一般毒性较弱 ;三价砷离子对细胞毒性最强 ,如三氧化二砷、三氯化砷、亚砷酸、砷化氢等砷的化合物 ,都有剧烈毒性 ;五价砷离子毒性不强 ,当吸入五价砷离子时 ,产生中毒…     

复合钛盐混凝剂的制备及其除砷效果的研究

采用简单的水解方法制备了一种新型复合钛铁混凝剂,用于去除饮用水中的砷。考察了pH值、混凝剂投加量、砷初始浓度、水力条件和共存离子等因素对砷去除效果的影响。结果表明,在pH=7,原水砷浓度为0.150mg/L,2#混凝剂投加量为10mg/L时,可使滤后水中砷浓度为8.44μg/L(10μg/L);混凝剂加入量为10mg/L,对较高浓度的As(Ⅲ)仍具有很高的去除率,可使含砷量为0.500mg/L的原水去除率达到89.81%。水力条件对除砷效果的影响不大;混凝除砷的适宜pH为6～8;碳酸根(HCO3-)和磷酸根(H2PO42-)等共存离子对砷的去除有一定的抑制作用。     

Novel technology on preparation of double-layered pellets for sulfur and arsenic-bearing gold concentrates

Double-layered pellet （DLP） roasting is a novel pretreatment method for sulfur and arsenic-bearing gold concentrates. In this process, preparation of DLPs is a fundamental step which is required to produce DLPs with favorable mechanical strength and thermal stability. Studies were carried out to investigate the affecting factors and conditions on the preparation and properties of DLPs. The results show that moisture content has significant influence on DLPs preparation. With the increase of moisture content in the range of no more than 9.8%, drop resistance and compressive strength of green DLPs are raised and the pelletizing dynamics is improved accordingly. The optimum conditions are determined as moisture content of 9.8%, coating time of 14-16 min, drying temperature 〈80 ℃and drying gas velocity 〈1.2 m/s. When DLPs prepared under these conditions are roasted at 600 ℃ for 1 h, favorable removal and solidifying rates can be obtained, in which the removal rates of arsenic and sulfur are 94.38% and 82.55%, and the solidifying rates of arsenic and sulfur reach 99.62% and 99.79%, respectively. These results promise industrial application of DLP roasting.