含砷矿石细菌氧化液除砷实验及砷钙渣稳定性研究

以甘肃某金矿经细菌氧化提金后产生的高砷、高铁强酸性细菌氧化液为研究对象，并选择CaO作为沉淀剂进行中和除砷实验，考察pH值、温度、搅拌速度和反应时间等对中和除砷的影响，通过单因素实验确定最佳除砷条件，并探究在模拟自然环境下各因素对砷钙渣稳定性的影响。除砷实验结果表明：在pH=4~5、搅拌速度适宜及常温下反应25 min时，除砷率可达99.99%，实现了废水净化；砷钙渣定量分析结果表明：渣中As、Fe质量分数分别为4.04%和19.79%；模拟自然环境下砷钙渣稳定性影响实验结果表明：当环境pH≤1时，砷钙渣中的砷被溶出了5 mg/L，超过工业废水排放标准。通过试验发现，选择CaO作为沉淀剂对细菌氧化液进行中和除砷，可以实现废水净化，并且当含砷渣所处环境pH≥1时可以稳定存放。

Study on Arsenic Removal from Bacterial Oxidation of Liquid Arsenical Ores and Stability of Arsenic Calcium Residue

Taking strong acid bacterial oxidation liquid with high arsenic and high iron produced by the bacterial oxidation gold extraction of one gold mine in Gansu Province as the research object，and selecting calcium oxide as precipitant to carry out the experiment of neutralization and arsenic removal.Through investigated the effect of the parameters such as pH value，temperature，stirring speed and reaction time on neutralization and arsenic removal，the best arsenic removal conditions were determined by single factor test. The influence of arsenic and calcium residue stability in simulated natural environment was explored.The results of arsenic removal test showed that the arsenic removal ratio was 99.99% under the optimal condition：pH=4~5，suitable stirring speed，reaction for 25 min at normal temperature and achieved the purification of waste liquid.The results of quantitative analysis of arsenic and calcium residue showed that the content of As and Fe in residue were 4.04% and 19.79% respectively.The experimental results on the stability of arsenic and calcium residue in simulated natural environment showed that：when the pH value was lower than 1，the arsenic in residue was dissolved out of 5 mg/L，exceeding emission standards of industrial waste.According to the results，it is possible to purify the wastewater by neutralizing arsenic with calcium oxide as precipitant，and the arsenic containing could be stored when the environmental pH≥1.