Alumina & Bauxite: On-Demand Oral Presentations
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Roberto Seno, Cba; Dmitry Eskin, Brunel University

Monday 8:00 AM
March 14, 2022
Room: Light Metals
Location: On-Demand Room

Fast Solution of Shrinking Core Model for Calcination Applications: Vladimir Golubev1; Dmitriy Chistyakov1; Dmitriy Mayorov1; Evgeniy Fomichev1; Iliya Blednykh1; 1Rusal Etc
    The shrinking core model is used in many applications, including simulations on alumina and limestone calcination. It helps to predict product properties, i.e. phase composition, reactivity and strength. Its application is limited by computational costs and the complexity of known numerical solutions of transfer equations for mass, heat, concentration and moment in the core and shell of a particle with moving reaction front, where the material properties are broken. The paper proposes to integrate the shrinking core model equations using a deep learning neural network which allows obtaining a high-quality solution much faster as compared with finite difference methods. The paper discusses the examples demonstrating the use of a new fast solver in the model of alumina flash calciner to calculate LOI for each particle size grade. The paper demonstrates the similar way to solve the problem of burning limestone in a shaft kiln.

Green Alumina: A Technological Roadmap: Alessio Scarsella1; Edgar Gasafi1; 1Metso Outotec
    The Green Aluminium phenomena although recent in notion, has been materializing over the last century with the first dedicated hydroelectric power stations for Aluminium production being commissioned early in the 20th century. With the EU emission target strategy in full swing, individual producers setting their own values and speculation on the formation of a newly indexed metal, producers, technology suppliers and regulators are trying to common ground to materialize a niche portion of Aluminium production to meet the emission related targets. The carbon dioxide makeup of Aluminium production is dominated by the electrolytic reaction followed by the anode consumption and then the Bayer process. Industry has spent significant efforts in decarbonizing the former two, the later still needing strong conceptual development. This paper intends to explain the conceptual contribution towards Green Aluminium from the perspective of a Bayer process technology supplier.

Potential of Alumochloride Technology for Production of Competitive Products: Andrei Smirnov1; Dmitriy Kibartas1; Alexander Senyuta1; Vladimir Bayanov1; Andrey Knyazev1; Andrey Panov1; 1RUSAL ETC
    Alumochloride technology can be used to obtain high value-added products from natural or industrial raw materials. Such products include, for example, pseudoboehmite used for refining catalysts. Pilot samples have been successfully tested for distillate hydrotreating to produce Euro-5 compliant diesel fuel (< 10 ppm residual sulfur). One more product is polyaluminum chloride that is used as a coagulant for potable water conditioning and effluent treatment. The said process complies with international standards and allows varying Cl/Al ratio within the range of 1.2-2.4 thus enabling to select the coagulant for different water type. Moreover, the process of production high purity aluminum (5N) has been developed. This product is used to grow sapphires (for LED, smartphone screens) and to cover separators for Li-ion batteries to improve their thermal stability and power intensity. The proposed processes can be established as individual production set-ups or integrated into alumina production by the alumochloride technology.

Removal of Fluorine, Chlorine, Nitrogen from Aluminum Dross by Wet Process: Xinxin Zhao1; Yan Liu1; Guozhi Lyu1; Yubin Zhang2; Ting-an Zhang1; 1Northeastern University; 2Shenyang Aluminum Magnesium Engineering Research Institute Co., Ltd.
    Aluminum dross is a hazardous solid waste produced in the process of electrolytic aluminum or cast aluminum production, with annual emission of more than 3 million tons. Fluoride, aluminum nitride and soluble salts contained in aluminum dross lead to environmental pollution and health hazard. In this paper, a method of harmless treatment of secondary aluminum dross was proposed. The effects of temperature, liquid-solid ratio, time and stirring speed on removal rate of nitrogen, fluorine and chlorine were investigated in detail. The results showed that the removal rates of each element reached the maximum at temperature of 80℃, liquid-solid ratio of 3:1, time of 2 h, and stirring speed of 400 r/min. The removal rates of nitrogen and fluorine were 62.8% and 77.6%, respectively, and the chlorine was completely removed. The research provides possibility for the harmless treatment and resource utilization of secondary aluminum dross.

Results of Metso: Outotec Calciner Optimizer Operation at CBA Alumina Calcination Plants: Steffen Haus1; Allan Borges1; Natalia Almeida2; Anderson Duck2; 1Outotec GmbH & Co. KG; 2Companhia Brasileira de Alumínio
     The Metso:Outotec Calciner Optimizer is a digital solution to actively control and optimize Alumina Calcination plants. It is today in continuous, close to 100% availability, operation at Companhia Brasileira de Alumínio (CBA). The paper covers the architecture of the digital solution, the impact on CBA Calciner operation and how detailed process understanding is integrated in a digital form into the daily process operation. The close cooperation between CBA process experts and Metso Outotec digital and process experts forms the basis of a successful implementation. Results are shown and discussed in this paper, proving significant energy savings when operating the plant with the Optimizer.Using the Optimizer provided a reduction in specific fuel gas consumption and greenhouse gas emissions. Further, the fluid bed calcination process know-how, combined with the advanced digital Optimizer solution, represents an enabler for future operational improvements.

Recovery of Iron from High-iron Bayer Red Mud by Melting Reduction with Spent Cathode Carbon Block: Xiaofei Li1; Ting-an Zhang1; Kun Wang1; Guozhi Lyu1; Xin Chen1; 1Northeastern University
    Red mud and spent cathode carbon block are two major solid wastes of the aluminum industry.In this study,an innovative method has been proposed for co-treatment of red mud and waste cathode carbon block to reuse carbon and recover iron by melting reduction.The effects of parameters such as temperature,alkalinity,reaction time and the CaF2 addition on the process were investigated.According to the experiment, the suitable reaction conditions were the reduction temperature of 1350℃, the alkalinity of 1.0, the reaction time of 30 minutes and the optimal CaF2 addition was 10g.The Fe recovery rate was 91.60% which can be directly used for electric furnace steelmaking.This work should help to improve the future large-scale, high-value and zero waste utilization of red mud.It was also of great significance for the harmless treatment of spent cathode carbon blocks and alleviating the shortage of iron ore resources in China.