scholarly journals Investigation of iron grains growth during solid-phase carbothermic reduction of red mud in the presence of iron metallic particles

2020 ◽  
Vol 848 ◽  
pp. 012099
Author(s):  
A S Zakunov ◽  
P I Grudinsky ◽  
D V Zinoveev ◽  
A F Semenov ◽  
M O Panova ◽  
...  
Keyword(s):  
Red Mud ◽  
Carbothermic Reduction ◽  
Solid Phase ◽  
Metallic Particles

scholarly journals Influence of Sodium Sulfate Addition on Iron Grain Growth during Carbothermic Roasting of Red Mud Samples with Different Basicity

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1571
Author(s):  
Pavel Grudinsky ◽  
Dmitry Zinoveev ◽  
Denis Pankratov ◽  
Artem Semenov ◽  
Maria Panova ◽  
...  
Keyword(s):  
Magnetic Separation ◽  
Grain Growth ◽  
Red Mud ◽  
Sodium Sulfate ◽  
Phase Distribution ◽  
Solid Phase ◽  
Alumina Production ◽  
Metallic Particles ◽  
Iron Phase ◽  
High Alkalinity

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.

scholarly journals Extraction of Iron from Russian Red Mud by a Carbothermic Reduction and Magnetic Separation Process

2021 ◽  
Vol 3 (1) ◽  
pp. 23
Author(s):  
Dmitry Zinoveev ◽  
Alexander Petelin ◽  
Pavel Grudinsky ◽  
Andrey Zakunov ◽  
Valery Dyubanov
Keyword(s):  
Experimental Data ◽  
Magnetic Separation ◽  
Grain Growth ◽  
Red Mud ◽  
Carbothermic Reduction ◽  
Iron Reduction ◽  
Solid Phase ◽  
Reduction Process ◽  
Alumina Production ◽  
Average Size

Red mud is a hazardous waste of alumina production. Currently, the total accumulated amount of red mud is over 4 billion tons. The promising method of red mud processing is a carbothermic reduction of iron at 1000–1400 °C into metallic form followed by magnetic separation. In this study, the mechanism of carbothermic solid-phase reduction of red mud was investigated. Based on the experimental data, the two-step mechanism of the first rapid stage of the process was proposed, which leads to almost full iron reduction. The estimated value of activation energy has indicated that solid-phase diffusion is a rate-controlling step for this stage. However, an almost full reduction is necessary, but insufficient factor for successful magnetic separation. The second crucial factor of the process is enlargement of iron grain size, which leads to gangue-grain release during grinding and increases efficiency of the magnetic separation. The prediction model of iron grain growth process during the carbothermic reduction process was suggested. The calculation of average size of iron grains formed during the reduction process that was performed according to the assumption of diffusion-controlled process showed their correlation with experimental data. Various methods were proposed to promote the process of iron grain growth during carbothermic reduction of red mud.

scholarly journals The Research of the Carbothermic Solid–Phase Red Mud Reduction Process in the Presence of Sodium Sulphate

2020 ◽  
Author(s):  
Dmitry Zinoveev ◽  
Pavel Grudinsky ◽  
Artem Semenov ◽  
Valery Dyubanov ◽  
Alexander Petelin
Keyword(s):  
Red Mud ◽  
Carbothermic Reduction ◽  
Solid Phase ◽  
Reduction Process ◽  
Sodium Sulphate ◽  
Alumina Production ◽  
Sodium Salts ◽  
Iron Extraction ◽  
Reduction Of Iron ◽  
Effective Technology

Russia has accumulated about 600 million tons of the red mud that is alumina production waste generated by Bayer method, but currently only a small amount of the total accumulated red mud is recycled. Solid–phase carbothermic reduction of red mud in the presence of sodium salts with magnetic separation can be a promising method for iron extraction. In this paper, the effect of the addition of sodium sulphate on the reduction of iron–containing phases and the growth of iron grains during solid–phase carbothermic reduction of red mud was investigated. The results show that 10% sodium sulphate additive significantly accelerate the growth of reduced iron grains, but decrease the degree of its reduction at temperatures above 1100∘C. The explanation of mechanism of sodium sulphate effect on the iron grain growth was proposed. Optimization of sodium sulphate amount, temperature and holding time can lead the development of effective technology of iron extraction from red mud by solid–phase carbothermic reduction. Keywords: red mud, solid–phase carbothermic reduction, sodium sulphate

scholarly journals STUDY ON DYES ADSORPTION FROM AQUEOUS SOLUTION USING RED MUD ACTIVATED BY SULFURIC ACID

2019 ◽  
Vol 62 (11) ◽  
pp. 143-149
Author(s):  
Vu Xuan Minh ◽  
Nguyen Tuan Dung ◽  
Hương T. M. Le
Keyword(s):  
Red Mud ◽  
Textile Industry ◽  
Solid Phase ◽  
Second Order ◽  
Iron Sulfate ◽  
Activation Process ◽  
Acid Activation ◽  
Order Kinetic ◽  
Adsorption Capacities ◽  
Reactive Red 195

The textile industry wastewater contains the majority of different dyes which are quite toxic and should be removed before disposal. They are often highly resistant for biodegradation and hence are difficult to be treated. The application of adsorbents of natural origin, especially industrial waste, is one of the most attractive solutions for wastewater treatments due to its high socio-economic advantages. In this study, the adsorption capacity of acid activiated red mud for some conventional dyes such as Reactive Red 195 and Direct Yellow 132 was investigated. In this acid activation process part of aluminum oxide, iron oxide on red mud will be dissolved into solution, thereby increasing the specific surface area of the remaining solid phase (from 55 m2/g to 92 m2/g). The amount of red mud dissolved in the solution is about 30% weight. Solid residue is used in this adsorption study. The solution obtained after activation which includes iron sulfate salts, aluminum sulfate used as a coagulant for wastewater treatment. The results showed that, for both dyes, pH 5 is most suitable for the adsorption processes. The adsorption kinetic was based on the pseudo second-order kinetic equation. The rate constants of the second-order model for adsorption of DY132, RR195 on RMA in a solution with a concentration of 100 mg·l-1, pH = 5 are 1.48 and 1.95·10-2 g/(mg·min), respectively, and the equilibrium adsorption capacities are 42.74 and 54.95 mg·g-1, respectively. The adsorption data were well matched to Langmuir isotherm model. The maximum adsorption capacities were found to be 48.54 and 84.31 (mg·g-1) for Reactive Red 195 and Direct Yellow 132, respectively.

scholarly journals Correction to: “Advanced Method for Recycling Red Mud by Carbothermal Solid-Phase Reduction Using Sodium Sulfate”

Metallurgist ◽  
2020 ◽  
Vol 63 (11-12) ◽  
pp. 1345-1345 ◽  
Author(s):  
P. I. Grudinskii ◽  
D. V. Zinoveev ◽  
A. F. Semenov ◽  
A. S. Zakunov ◽  
V. G. Dyubanov ◽  
...  
Keyword(s):  
Red Mud ◽  
Sodium Sulfate ◽  
Solid Phase ◽  
Advanced Method ◽  
Phase Reduction

Solid-phase carbothermic reduction of the components of chrome-iron ore raw materials

2011 ◽  
Vol 2011 (12) ◽  
pp. 1128-1130
Author(s):  
O. V. Zayakin ◽  
V. I. Zhuchkov ◽  
D. D. Izbembetov ◽  
O. E. Privalov ◽  
M. M. Kospanov
Keyword(s):  
Carbothermic Reduction ◽  
Iron Ore ◽  
Solid Phase ◽  
Raw Materials

Solid-Phase Reduction and Iron Grain Growth in Red Mud in the Presence of Alkali Metal Salts

2018 ◽  
Vol 2018 (11) ◽  
pp. 1020-1026 ◽  
Author(s):  
P. I. Grudinskii ◽  
V. G. Dyubanov ◽  
D. V. Zinoveev ◽  
M. V. Zheleznyi
Keyword(s):  
Alkali Metal ◽  
Grain Growth ◽  
Red Mud ◽  
Solid Phase ◽  
Metal Salts ◽  
Alkali Metal Salts ◽  
Phase Reduction

scholarly journals Influence of Na2CO3 and K2CO3 Addition on Iron Grain Growth during Carbothermic Reduction of Red Mud

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1313 ◽  
Author(s):  
Dmitry Zinoveev ◽  
Pavel Grudinsky ◽  
Andrey Zakunov ◽  
Artem Semenov ◽  
Maria Panova ◽  
...  
Keyword(s):  
Magnetic Separation ◽  
Grain Growth ◽  
Red Mud ◽  
Carbothermic Reduction ◽  
Reduction Roasting ◽  
Alumina Production ◽  
Iron Aluminum ◽  
Bauxite Ore ◽  
Hsc Chemistry ◽  
Sodium And Potassium

Red mud is a by-product of alumina production from bauxite ore by the Bayer method, which contains considerable amounts of valuable components such as iron, aluminum, titanium, and scandium. In this study, an approach was applied to extract iron, i.e., carbothermic reduction roasting of red mud with sodium and potassium carbonates followed by magnetic separation. The thermodynamic analysis of iron and iron-free components’ behavior during carbothermic reduction was carried out by HSC Chemistry 9.98 (Outotec, Pori, Finland) and FactSage 7.1 (Thermfact, Montreal, Canada; GTT-Technologies, Herzogenrath, Germany) software. The effects of the alkaline carbonates’ addition, as well as duration and temperature of roasting on the iron metallization degree, iron grains’ size, and magnetic separation process were investigated experimentally. The best conditions for the reduction roasting were found to be as follows: 22.01% of K2CO3 addition, 1250 °C, and 180 min of duration. As a generalization of the obtained data, the mechanism of alkaline carbonates’ influence on iron grain growth was proposed.

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