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Metal Manufacturing Processes and Energy Systems
Published in Swapan Kumar Dutta, Jitendra Saxena, Binoy Krishna Choudhury, Energy Efficiency and Conservation in Metal Industries, 2023
Swapan Kumar Dutta, Binoy Krishna Choudhury
Aluminum is unique, being the most extensively available metal on Earth’s crust (8%). It is infinitely recyclable (more than 75% of the aluminum ever produced from bauxite is still in use), features military-grade durability and corrosion resistance (a thin permanent coating of aluminum oxide protects the metal from any further corrosion or attrition), and is lightweight and energy efficient (as much less load in engines, automobiles, airplanes, etc.). Aluminum is now recognized as a sustainable metal of choice for modern transportation, building construction and packaging industries, etc.
Effect of sintering temperature on the alumina extraction from kaolin
Published in Vladimir Litvinenko, Advances in Raw Material Industries for Sustainable Development Goals, 2020
A.B. ElDeeb, V.M. Sizyakov, V.N. Brichkin, R.V. Kurtenkov
The aluminum industry is one of the fastest growing global sectors in the world, especially among developing countries. Increased worldwide demand for aluminum oxide, currently at more than 160 million tons per year, is expected to lead to a gradual global decline of high-grade bauxite, the ore from which alumina is mainly produced using the Bayer process. Many aluminum-producing countries have thus become increasingly interested in the investigation of producing alumina from non bauxitic sources (ElDeeb et al., 2019, Cohen & Mercier, 2016, Protosenya & Trushko, 2007).
Metals in the workplace
Published in Sue Reed, Dino Pisaniello, Geza Benke, Kerrie Burton, Principles of Occupational Health & Hygiene, 2020
Aluminium is a relative newcomer to the family of commercial metals. In its mineral form, bauxite, aluminium is the most abundant metal in the earth’s crust. Mined bauxite is refined into alumina (aluminium oxide) using a chemical refining process (Bayer), whereby finely ground bauxite is digested in a hot caustic soda solution, then clarified, precipitated and calcined. The alumina is then smelted into aluminium using electrochemical reduction, whereby the alumina is dissolved in molten cryolite in cells through which a direct electrical current is passed via carbon cathodes and anodes. The molten metal formed in each cell is drawn off at regular intervals for casting into various shapes. Aluminium is often alloyed with small amounts of copper, magnesium, silicon, manganese and other elements to impart a variety of useful properties.
Impact assessment of waste screening over the life of a Brazilian bauxite mining operation
Published in Mining Technology, 2021
Luana Teixeira Pontara Lopes, Fernando Cesar Fernandes Junior, Edmo da Cunha Rodovalho, Thammiris Mohamad El Hajj
After being mined, the bauxite ore is ground and then chemically treated using the Bayer process, which is an industrial method of bauxite pressure digestion in strong sodium hydroxide caustic solutions. As a result, aluminium hydroxide is selectively extracted, crystallised from the process liquor and calcined to metallurgical grade alumina (Goronovski et al. 2019). In this study, the cut-off grades to feed the Bayer process are 40% of the available alumina (AA) concentration, less than 4% of reactive silica (RS) and less than 0.5% of organic carbon content (OCC) (ABAL 2008). These values are required because contaminants in the Bayer (e.g. RS and OCC) decrease the process performance, alter the alumina colour and can sediment the liquor (Liu et al. 2018). The presence of organic compounds in the digestion liquor in the Bayer process has adverse effects, such as a decrease in process productivity, modification of the liquor, alteration in the alumina colour and reduction in the strength of the aluminium. The combined effects increase the use of raw materials and reduce the production efficiency and product quality (Grocott 1988).
Level and Potential Risk Assessment of Soil Contamination by Trace Metal from Mining Activities
Published in Soil and Sediment Contamination: An International Journal, 2021
Manh Ha Nguyen, Huu Tap Van, Phan Quang Thang, Thi Huyen Ngoc Hoang, Dinh Cham Dao, Cong Long Nguyen, Lan Huong Nguyen
Bauxite mining area: the high content group was Cu (25.50–41.73 mg/kg) and Zn (31.54–52.95 mg/kg). The following content order to a sequence: Pb>As>Hg>B> Cd>Mo. Zn content at bauxite of Bao Loc and Tan Rai was the highest compared to other elements. The content of Mo was the lowest level at Tan Rai and Nhan Co areas. Almost elements was observed to lower than that of Kuantan bauxite area in Malaysia (David et al. 2016). The soil pollution sources at Bauxite mining sites (Bao Loc, Tan Rai, and Nhan Co) were quite similar, including the coal gasification and aluminum plants, tailings waste sludge lakes, red mud lakes, exploitation areas, and postmining waste dumps. The coal gasification and aluminum plants generated the solid wastes such as coal slag, ore slag and the dust from large-capacity machines. The tailings waste sludge lakes contained waste sludge after washing ore, mainly sludge sticked on the ore. The red mud lake contained mud after enriching process aluminum from ore which was mixed with many chemicals, especially NaOH. This mud was easy to leak into the environment causing soil pollution.
Fluoride removal from water using alumina and aluminum-based composites: A comprehensive review of progress
Published in Critical Reviews in Environmental Science and Technology, 2021
Sikpaam Issaka Alhassan, Lei Huang, Yingjie He, Lvji Yan, Bichao Wu, Haiying Wang
Bauxite is a naturally existing ore obtained from the production of aluminum. Generally, it has several aluminum minerals with oxides of silica, iron, titanium and other trace impure metals. Several studies on using bauxite for wastewater remediation have characterized bauxite into its components. However, slight variation in its composition exists depending on its origin. The composition of typical bauxite is shown below in Table 5.