Chinese Bauxite and Its Influences on Alumina Production in China

Author(s):  
Gu Songqing
Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1571
Author(s):  
Pavel Grudinsky ◽  
Dmitry Zinoveev ◽  
Denis Pankratov ◽  
Artem Semenov ◽  
Maria Panova ◽  
...  

Red mud is an iron-containing waste of alumina production with high alkalinity. A promising approach for its recycling is solid-phase carbothermic roasting in the presence of special additives followed by magnetic separation. The crucial factor of the separation of the obtained iron metallic particles from gangue is sufficiently large iron grains. This study focuses on the influence of Na2SO4 addition on iron grain growth during carbothermic roasting of two red mud samples with different (CaO + MgO)/(SiO2 + Al2O3) ratio of 0.46 and 1.21, respectively. Iron phase distribution in the red mud and roasted samples were investigated in detail by Mössbauer spectroscopy method. Based on thermodynamic calculations and results of multifactorial experiments, the optimal conditions for the roasting of the red mud samples with (CaO + MgO)/(SiO2 + Al2O3) ratio of 0.46 and 1.21 were duration of 180 min with the addition of 13.65% Na2SO4 at 1150 °C and 1350 °C followed by magnetic separation that led to 97% and 83.91% of iron recovery, as well as 51.6% and 83.7% of iron grade, respectively. The mechanism of sodium sulfate effect on iron grain growth was proposed. The results pointed out that Na2SO4 addition is unfavorable for the red mud carbothermic roasting compared with other alkaline sulfur-free additives.


2021 ◽  
Vol 410 ◽  
pp. 806-811
Author(s):  
Kapar Sh. Aryngazin ◽  
Alexey V. Bogomolov ◽  
Askar K. Tleulessov

The article discusses the experience of recycling industrial waste from the electric power industry and metallurgy. Based on the experience of Ecostroy NII-PV LLP. The proposed technology for manufacturing building products from ash and slag waste provides innovative compositions of raw mixtures. What provides an increase in operational characteristics and labor productivity in construction. The applied technology, in comparison with the existing analogues, provides for the use of local waste (ash and slag waste from the combustion of Ekibastuz coal, bauxite sludge from the Pavlodar aluminum plant, steel-making slags), differing in chemical and granulometric composition. as well as binding properties from other analogs and prototypes. In the manufacture of building products introduced mixture, including, wt %: slag Portland cement - 14.32-17.00; sand - 18.74-25.52, crushed stone - 46.50-49.71, sludge from alumina production obtained during the recycling of bauxite from Kazakhstan - 5-7; self-disintegrating steelmaking slag - 5-7; ash and slag waste from thermal power plants from burning Ekibastuz coals - 5-7. According to the test results, the average tensile strength of building products (paving slabs, curbs, hollow bricks) is 3.2 - 3.8 MPa (strength class V2.5).


2021 ◽  
Vol 5 (1) ◽  
pp. 66
Author(s):  
Panagiotis Angelopoulos ◽  
Maria Georgiou ◽  
Paschalis Oustadakis ◽  
Maria Taxiarchou ◽  
Hakan Karadağ ◽  
...  

Bauxite Metallurgical Residue (BR) is a highly alkaline and very fine-grained by-product of the Bayer process for alumina production. Its huge global annual production has resulted in increasing accumulation of BR, causing deposition problems and serious environmental issues. RM contains oxides and salts of the main elements Fe, Al, Ca, Na, Si, Ti, and rare earths—REEs (Sc, Nd, Y, La, Ce, Ds)—many of which have been categorised by EU as critical metals (CMs). The valorisation of BR as a low-cost secondary raw material and metal resource could be a route for its reduction, introducing the waste into the economic cycle. REEScue constitutes a research project that aims to instigate the efficient exploitation of European bauxite residues, resulting from alumina production from Greece (MYTILINEOS SA), Turkey (ETI Aluminium), and Romania (ALUM SA), containing appreciable concentrations of scandium and REEs, through the development of a number of innovative extraction and separation technologies that can efficiently address the drawbacks of the existing solution. The consortium consists of three alumina producers from Greece (MYTILINEOS SA), Turkey (ETI Aluminium), and Romania (ALUM SA) and two academic partners from Greece (National Technical University of Athens) and Turkey (Necmettin Erbacan University). We present preliminary characterization results of three different BR samples that originate from the three aluminium industries, in respect of bulk chemical analysis (XRF, ICP), mineralogical investigation (XRD), and morphological observation through microscopy.


2020 ◽  
Author(s):  
Ekaterina Gerasimova ◽  
Elizaveta Gumirova

The paper deals with the problem of utilization of red mud which is a waste product from alumina production using the Bayer method. The principal possible use for the red mud of JSC “Bogoslovsky aluminum plant” (Sverdlovsk region) for the compositions based on Portland cement is shown. It was found that the mud introduction accelerates beginning of the cement paste setting and thickens the paste reducing its mobility. It is concluded that the introduction of red mud up to 30 % is justified in terms of strength indicators. The work is carried out using mathematical planning of experiments. Keywords: red mud, Portland cement, active mineral additive, composition, properties, bauxite, chemical composition, cement stone strength, mathematical planning of experiments


2020 ◽  
Vol 24 (Suppl. 1) ◽  
pp. 31-37
Author(s):  
Shu Zhang ◽  
Wei Wang ◽  
Hong Sun ◽  
Dumitru Baleanu

This paper provided a numerical simulation of fluid dynamics in the chemical vapor reactor for nanoparticle synthesis. Standard k-? turbulence equation and eddy-dissipation model with standard wall function were used to investigate the reaction process of turbulent diffusion for alumina production. Here the tempera?ture and the operating conditions are discussed. Numerical results show that the model can well describe synthesis of nanometer alumina. The chemical reactions for alumina by this reactor are mainly concentrated in the range of 200 mm after the nozzle. The materials are completely mixed after 400 mm in the reactor.


2021 ◽  
Vol 5 (1) ◽  
pp. 53
Author(s):  
Andriani Manataki ◽  
James M. Mwase ◽  
Casper van der Eijk

The Pedersen process is an alumina production process, which combines pyrometallurgical and hydrometallurgical methods. In the pyrometallurgical stage, limestone is calcined and CO2 is generated. This off-gas can be captured with a high CO2 concentration. At the end of the hydrometallurgical process, aluminum hydroxides, like bayerite, are precipitated using CO2. In this paper, experimental work on precipitation of aluminum hydroxides through the addition of a mixture of CO2, O2 and N2 is presented. The parameters varied, as were the percentages of each gas and the temperature. The indicators measured were the time until the beginning of precipitation and the time that the precipitation lasts. These tests simulate the use of a smelter furnace off-gas in the precipitation stage of the Pedersen process and have shown promising results.


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