Enhancing sulphide-based arsenic precipitation for treatment of metallurgical waste streams to reduce environmental impact

由于高品位矿石的枯竭，金属的生产需要随着砷含量的增加而加工低品位矿石。加工这种类型的原材料会将砷引入冶金电路，导致产生含有砷的废气，砷是有毒和致癌的。BQE Water是一家水处理服务提供商，在受矿山影响的水和工艺解决方案处理和管理方面拥有专业知识，我们与BQE Water合作，建议加强硫化物沉淀法，以去除和稳定砷作为高砷含量的三硫化砷。与现有的脱除方法相比，由于砷含量高，这种硫化过程产生的砷废物副产量最少，可高达60%，比目前方法产生的5%-30%的含量有很大提高。然而，由于三硫化砷的溶解性和对大气和细菌氧化的敏感性，其稳定性是一个主要问题。因此，拟议项目将解决的关键技术挑战是评估和制定一项战略，以提高三硫化砷在各种条件下的稳定性，特别是与现场安全储存相关的条件。强化的硫化工艺与BQE水务的战略技术开发非常一致。产生的新知识将加强现有的专门知识，并促进其在砷管理领域的业务。虽然过去曾使用硫化去除砷，但加强处理过程和最终副产品的稳定性将使矿业公司能够以更安全的环境方式处理含砷矿石，以提取有价值的金属。鉴于矿产部门对加拿大经济的重要性，拟议进程的实施将为加拿大带来巨大的经济、社会和环境效益。拟议的项目将培训1名博士后研究员和2名本科生研究助理。

Due to the depletion of high grade ores, production of metals necessitates processing of lower grade ores with increasing levels of arsenic. Processing this type of raw materials introduces arsenic into the metallurgical circuits, resulting in the generation of waste streams that contain arsenic, which is toxic and carcinogenic. In partnership with BQE Water, a water treatment service provider with expertise in mine impacted water and process solution treatment and management, we propose to enhance a sulphide-based precipitation process that removes and stabilizes arsenic as arsenic trisulphide with high arsenic content. Compared with the existing removal methods, this sulphidization process will generate the least volume of arsenical waste by-product due to the high arsenic content, which could reach as high as 60%, a substantial increase from the 5-30% content that results from current methods. However, the stability of arsenic trisulphide is a major concern due to its solubility and susceptibility to atmospheric and bacterial oxidation. Therefore, the key technical challenge the proposed project will address is to assess and devise a strategy to enhance the stability of the arsenic trisulphide under a variety of conditions, specifically those relevant for safe storage in the field. The enhanced sulphidization process aligns well with the strategic technology development at BQE Water. The new knowledge generated will strengthen the existing expertise and facilitate its business in the area of arsenic management. While sulphidization has been used in the past for arsenic removal, enhancing the process and the stability of the final by-product of treatment will enable mining companies to process arsenic-bearing ores for extraction of valuable metals in an environmentally safer manner. Given the importance of the minerals sector to the Canadian economy, the implementation of the proposed process will bring enormous economic, social and environmental benefits to Canada. The proposed project will train 1 postdoctoral fellow and 2 undergraduate research assistants.