Thermodynamic evaluation of waste residues pertaining to the reuse of industrial waste and contaminated sites

赤泥是从铝土矿中提取氧化铝时产生的一种富铁残渣。大约2-4吨这种赤泥材料是为生产一吨铝而产生的。由于这种废流的规模和腐蚀性，赤泥是一个主要的环境问题。在大多数情况下，赤泥储存在铝业公司附近的位置，需要相当大的土地才能做到这一点。因此，开发这种废渣的潜在应用，消除其对环境的影响，并帮助恢复受污染的场地，是一个重要的考虑因素。在钢铁工业的综合部门中，制造一吨钢水产生的炉渣约为400公斤。低磷低硫铁水加料可显著减少炼钢转炉弃渣。本方案的创新之处在于，将氧化铝生产中产生的废渣作为钢铁行业环保型精炼助熔剂的基础，以生产低残留杂质水平的铁水。这将减少加拿大工业对环境的影响，并确保腐蚀性化合物不会进入生态系统。为了实现这一目标，短期目标是：1)评估赤泥废渣的物理、化学和热特性以及通过向赤泥材料中添加碱性氧化物而产生的合成熔剂，2)使用等活度法研究控制赤泥基渣和铁水之间磷分配的基本热力学，3)使用渣-金属平衡法测量赤泥基渣的磷酸盐和硫化物容量，4)评估赤泥基渣对耐火衬里材料行为的影响，以及5)开发用于铁水前处理和钢水精炼的赤泥等原料冶金渣的定制设计模型。较长期的目标是为加拿大各行业提供高素质的人员，拥有矿物加工、材料生产、废物管理和环境控制方面的深入知识。

Red mud is an iron-rich residue that is produced during the extraction of alumina from bauxite. About 2-4 tonnes of this red mud material are generated for the production of one tonne of aluminum. Because of the size of this waste stream and its causticity, red mud is a major environmental concern. In most cases, the red mud is stored on location close to aluminum companies, and a considerable amount of land is required for this purpose. Development of potential applications for this waste residue that would eliminate its impact on the environment and help restore contaminated sites, is therefore an important consideration. Within the integrated sector of the steel industry, about 400 kg of slag is produced in making one tonne of liquid steel. The amount o disposed slag from the steelmaking converter can be significantly reduced when charging hot metal with low phosphorus and sulphur contents. The novelty of the present proposal is to use waste materials from alumina production as the basis for environment-friendly refining flux in the steel industry in order to generate hot metal with low residual levels of impurities. This will reduce the impact of Canadian industries on the environment and ensure that caustic compounds do not enter the ecosystem. To achieve this goal, the short-term objectives are: 1) To evaluate the physical, chemical and thermal characteristics of red mud waste products as well as synthetic fluxes generated by additions of basic oxides to the red mud materials, 2) To investigate the fundamental thermodynamics that govern phosphorus distribution between red mud based slags and hot metal using an iso-activity method, 3) To measure phosphate and sulphide capacities of red mud based slags using slag-metal equilibration, 4) To evaluate the effect of red mud based slags on the behaviour of refractory lining materials, and 5) To develop a model for the custom design of metallurgical slags derived from red mud and other materials for hot metal pretreatment and steel refining. A longer-term objective is to provide highly qualified personnel with in-depth knowledge in mineral processing, materials production, waste management and environmental control for Canadian industries.