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过程中产生的富铁残渣。一吨铝的生产大约会产生2 - 4吨这种赤泥材料。由于这种废物流的规模及其腐蚀性，赤泥是一个主要的环境问题。在大多数情况下，红泥储存在靠近铝公司的地方，为此需要大量的土地。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，生产一吨液态钢会产生约400公斤的炉渣。采用低磷、低硫铁水，可大幅度减少转炉出渣量。本提案的新颖性在于使用来自氧化铝生产的废料作为钢铁工业中的环境友好精炼熔剂的基础，以产生具有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。为实现这一目标，短期目标是：1）评价了赤泥废弃物的物理、化学和热特性以及在赤泥原料中添加碱性氧化物所产生的合成熔剂。2）采用等活度法研究了磷在赤泥基渣和铁水之间分配的基本热力学。3）采用渣-金属平衡法测定了赤泥基渣的磷容量和硫容量。4）评价了赤泥基渣对耐火炉衬材料性能的影响。和5）开发一种用于铁水预处理和钢精炼的从赤泥和其他材料中提取的冶金渣的定制设计模型。一个较长期的目标是为加拿大工业提供在矿物加工、材料生产、废物管理和环境控制方面具有深入知识的高素质人员。

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.