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.     

谢 铿 王海北 刘三平 苏立峰

对内蒙古某公司湿法炼锌产生的铅银渣和铁矾渣进行扩大试验,采用"洗涤—净化—萃取"工艺回收渣中夹带的水溶锌,铅银渣和铁矾渣中锌洗涤回收率分别达到42%和90%左右,铁去除率大于98%,萃取后得到的富锌溶液可送电积车间生产电锌。该工艺流程简单、原料适应性强、经济效益和社会效益显著。     

红土镍矿制备黄钠铁矾的研究

为确定红土镍矿酸化焙烧溶出液中硫酸镍溶液除铁的工艺条件,以低品位红土镍矿硫酸铵焙烧熟料溶出液为研究对象,Na2CO3为造矾试剂制备了黄钠铁矾。造矾最佳试验条件为:反应温度95℃、反应时间4 h、终点p H值为2.5,除铁率在99.5%以上,并采用XRD、SEM和化学分析手段对黄钠铁矾进行了物化表征,显示在此条件下所得到的黄钠铁矾具有分散性良好、外形规则的,包含多个光滑颗粒的花球状的结构。     

铁矾渣还原焙烧自硫化研究

为解决铁矾渣大量堆存带来的资源浪费和重金属污染,及传统焙烧回收处理工艺会产生SO_2等二次污染的问题,同时实现铁矾渣中主要有价金属的回收利用,提出了铁矾渣还原焙烧固硫的预处理方法。以铁矾渣热分解过程和热力学计算为基础,通过考察焙烧条件对铁矾渣中主要有价金属锌的硫化率、硫的固定率及物相转变的影响,对铁矾渣还原焙烧自硫化过程进行了研究。结果表明:在焙烧温度为900℃,碳粉添加量为18%,碳酸钠添加量为5%,焙烧时间为90min的条件下,锌的硫化率和硫固化率分别可达93.47%和87.69%。焙烧产物主要以硫化物形式存在,可通过浮选等方式富集。铁矾渣还原焙烧可以实现Zn等主要有价金属的综合回收预处理并避免焙烧过程中SO_2的排放。该研究对其它重金属硫酸盐的清洁处理具有重要的指导意义。     

红土镍矿选择性溶出制备黄铵铁矾花球状晶体

以红土镍矿硫酸焙烧熟料溶出液为原料,(NH_4)_2CO_3为碱式调节剂,采用湿法制备黄铵铁矾。研究和分析了反应温度、反应时间和pH值对溶出液中黄铵铁矾生成率的影响,并利用X射线衍射(XRD)、扫描电子电微镜(SEM)和化学成分分析等手段对制备产物进行了表征。研究发现,在反应温度95℃、反应时间4 h、终点pH值是2.5的条件下,黄铵铁矾生成率大于98%,实现了铁的有效分离,得到花球状黄铵铁矾粉体。     

生物浸铜反萃液生产硫酸铜除铁工艺

利用三种方法分别对某铜矿山生物浸铜反萃液生产饲料级五水硫酸铜的重要步骤——除铁工艺进行了深入研究,结果表明：采用黄铵铁矾法除铁,控制温度在95℃、pH=1．6,除铁率可以达到91．2％;采用氢氧化铁沉淀法,于70℃,pH=3．8的条件下,除铁率可达98．1％。但上述方法除铁过程会将NH4^ 、Na^ 和Ca2^ 等杂质带入硫酸铜溶液;采用一步结晶法,控制结晶温度在60℃、结晶时间为6h,除铁率可以达98．5％,该工艺操作简单,产品符合饲料级硫酸铜的国家标准。     

黄钾铁矾浸出工艺处理高铁矿控制对策

论述了高铁矿对浸出系统生产影响的几个方面,并对这些影响问题提出工艺控制条件,采取了处理控制对策,取得较好的生产效果。     

Synthesis of Ni-Zn ferfite and its microstructure and magnetic properties

Nanometer Ni0.5Zn0.5Fe2O4 powders with spinel phase were prepared by the hydrothermal method using purified FeSO4 solution from sodium jarosite＇s slag as materials. The results show that the spinel phase of Ni0.5Zn0.5Fe2O4 powders begins to form at a relatively low temperature （130 ℃） and a shorter holding time （1 h） when pH=8. The crystallization kinetics equation at 200℃ is ln[-ln（1-x）] =-0.78＋0.951n t. The growth activation energy of Ni0.5Zn0.5Fe2O4 grains is 41.6 kJ/moL in hydrothermal synthesis process. With the increase of sintering temperature, the density and diameter shrinkage of ferrite circulus increase, whereas its pores decrease. The results of magnetic measurements show that saturation magnetic flux density Bs increases and the coercivity Hc decreases with the increase of their sintering temperature. Magnetic parameters of all the investigated samples satisfy the character demand of high Bs, low Br and low Hc of soft magnetic ferrite materials.     

铁矾渣富氧强化还原挥发熔炼及熔炼终渣浸出毒性

铁矾渣是湿法炼锌过程中产生的一种含锌废渣,其大量堆存不仅对生态环境造成影响,还会导致有价金属资源的积压。采用富氧强化还原挥发熔炼工艺处理铁矾渣,考察反应时间、反应温度、配碳量、富氧浓度对熔炼过程铅、锌挥发率及熔炼终渣银含量的影响,并就熔炼终渣浸出毒性特征进行表征。结果表明,当反应温度为1 250 ℃、反应时间90 min、配碳量10%、富氧浓度40%时,铅、锌挥发率分别为99.66%、99.88%,熔炼终渣含银量为11.58 g/t,熔炼终渣浸出液中Cd、Zn、Pb、Cu、As浓度均低于TCLP国际标准限值和《GB 5085.3—2007》标准限值。