含砷废水是金矿的生物预氧化过程中产生的主要污染，其中含有高浓度的铁和砷。现有的石灰沉淀法处理这种废水会形成大量无定形沉淀，其含水量高，稳定性差，堆存成本较高。臭葱石和含砷黄铁矾都具有晶体结构，其含砷量高，稳定性强，均为性质优良的固砷物质。基于此，本论文研究了利用砷铁共沉淀法进行生物冶金废水除砷的过程，将砷转化为性质稳定且含水量低的结晶型砷铁沉淀，实现了砷的稳定化处理，对改善生态环境具有十分重要的意义。第一，研究了O3预氧化过程对砷铁共沉淀反应处理生物冶金废水的影响。用O3将废水中的As(III)预氧化为As(V)后再进行沉淀反应，有助于提高废水的除砷效果和沉淀的稳定性。废水经过O3预氧化后，在pH 2、pH 2-3和pH 2-4条件下反应时，废水的除砷率分别由93.18%、97.38%和98.20%提高至94.78%、99.76%和99.81%，沉淀的浸出砷浓度分别由2.62 mg/L、2.45 mg/L和3.67 mg/L降低至2.21 mg/L、0和0.31 mg/L。第二，分别考察了投加Fe(II)和投加金矿的影响。向废水中投加Fe(II)后，有助于提高废水的除砷率和沉淀的稳定性，沉淀均由含砷的黄钠铁矾晶体和少量含砷无定形沉淀组成。在pH 2、pH 2-3和pH 2-4条件下反应时，砷的去除率分别为99.14%、99.99%和100%。在pH 2条件下反应，沉淀在TCLP实验中的浸出砷浓度为0.27 mg/L；在pH 2-3和pH 2-4条件下反应，生成的沉淀在TCLP实验中未检测到砷的浸出。当矿物投加量为20%时，在pH 2条件下进行沉淀反应，砷的去除率为98.20%，沉淀由含砷的黄钠铁矾晶体和少量含砷无定形物质组成，沉淀的浸出液中未检测到砷；在pH 2-3和pH 2-4条件下进行沉淀反应，砷的去除率为100%，生成的含砷针铁矿稳定性强，无砷浸出。 第三，研究了As(V)-Fe(III)溶液中初始Fe(III)浓度对砷的去除率和臭葱石合成的影响。结果发现，溶液中初始Fe(III)/As(V)摩尔比大于0时，在升温过程中生成了无定形砷酸铁，当初始Fe(III)/As(V)摩尔比不超过1.6时，砷酸铁反应8 h后转化为臭葱石。随着初始Fe(III)/As(V)摩尔比的增大，砷的去除率增大，臭葱石沉淀的结晶度降低、浸出砷浓度降低，其中，初始Fe(III)/As(V)摩尔比为0.8和1.6时，臭葱石沉淀的浸出砷浓度低于5 mg/L，适合安全堆存。当初始Fe(III)/As(V)摩尔比大于1.6时，砷的去除率降低，无定形砷酸铁反应8 h后仍不能转化成臭葱石，沉淀的浸出砷浓度超标，不适合安全堆存。;Arsenic-containing wastewater is the main pollutant generated during the biological preoxidation of gold ores, which contains high concentrations of iron and arsenic. A common technique for immobilization of arsenic from the wastewater is lime neutralization. However, a large amount of amorphous precipitates are formed with high water content and poor stability, therefore it will take high costs for precipitates storage. Both scorodite and arsenic-bearing jarosite are ideal compounds for arsenic fixation with good properties of crystalline structures, high arsenic content and high stability. In view of this, the process of removing arsenic in biological metallurgical wastewater by coprecipitation of arsenic with iron was investigated in this thesis. In this process, the arsenic in wastewater was stabilized because it was fixed as crystalline arsenic-iron precipitate with high stability and low water content, which was of great significance to stable the arsenic and make it harmless.Firstly, the effect of preoxidation with ozone on the treatment of biological metallurgical wastewater by arsenic and iron coprecipitation reaction was investigated. The preoxidation of As(III) to As(V) in wastewater by ozone before precipitation was beneficial to increase the arsenic removal and to improve the stability of precipitates. It was found that after preoxidized by ozone, the arsenic removal ratios were improved from 93.18% at pH=2, 97.38% at pH=2-3 and 98.20% at pH=2-4 to 94.78%, 99.76% and 99.81% respectively. And the leached arsenic concentrations of the precipitates decreased from 2.62 mg/L, 2.45 mg/L and 3.67 mg/L, to 2.21 mg/L, 0 and 0.31 mg/L, respectively.Secondly, the effects of additional ferrous ions and gold concentrate were investigated, respectively. With the addition of ferrous ions, the arsenic removal ratio in wastewater and the stability of precipitates were improved. XRD and SEM results showed that the precipitates in wastewater consisted of crystalline arsenic-bearing natrojarosite and a small amount of arsenic-bearing amorphous substances. It was found that the arsenic removal ratios were 99.14% at pH=2, 99.99% at pH=2-3 and 100% at pH=2-4. The TCLP tests showed that the leached arsenic concentration was 0.27 mg/L for the precipitates formed at pH=2, and for the precipitates formed at pH=2-3 and pH=2-4, no leached arsenic detected in the TCLP tests. With the addition of gold concentrate at dosage of 20%, 98.20% of arsenic was removed when the precipitation was carried out at pH=2. The precipitates consisted of crystalline arsenic-bearing natrojarosite and a small amount of arsenic-bearing amorphous substances, and no arsenic was detected in the leaching solution. When the precipitation reactions of wastewater were carried out at pH=2-3 and pH=2-4, the arsenic in the wastewater was completely removed and the precipitates were arsenic-bearing goethite, which were very stable and no arsenic detected in the leaching solution.Thirdly, the effects of initial ferric ion concentration of the solution on the arsenic removal ratio and the scorodite formation were investigated in As(V)-Fe(III) system. In all the experiments with the additional ferric ions, it was found that there was amorphous ferric arsenate formed in the heating process. The amorphous ferric arsenate was found to be converted into crystalline scorodite in 8 hours if the molar ratio of Fe(III)/As(V) was not higher than 1.6. However, the crystallinity of scorodite decreased with the increase of additional ferric ion concentration, and the stability of the solid products and the arsenic removal ratio of the solution were improved. The results of the TCLP leaching test showed that at Fe(III)/As(V) of 0.8 and 1.6, more than 80% of arsenic could be precipitated as a form of scorodite. The arsenic leaching concentration of the formed solid products were less than 5 mg/L, which could meet the emission standards, so that the solid products may be considered to be stable for safe disposal. Nevertheless, if the molar ratio of Fe(III)/As(V) was higher than 1.6, the amorphous ferric arsenate could not convert into crystalline scorodite after 8 hours. The arsenic removal decreased and the amorphous ferric arsenate was unstable for high arsenic leaching concentration.