scholarly journals The effect of NaOH on the direct calcification–carbonation method for processing of Bayer process red mud

2018 ◽  
Vol 7 (6) ◽  
pp. 546-551 ◽  
Author(s):  
Liqun Xie ◽  
Tingan Zhang ◽  
Guozhi Lv ◽  
Jinlin Yang ◽  
Yanxiu Wang
Keyword(s):  
Solid Waste ◽  
Red Mud ◽  
Silicon Phase ◽  
Process Flow ◽  
Carbonation Process ◽  
Bayer Red Mud ◽  
Red Muds ◽  
Alumina Industry ◽  
Process Liquor ◽  
Alumina Recovery

Abstract The Bayer red mud generated from the alumina industry is a hazardous solid waste. In our team, a green calcification–carbonation process is proposed for its disposal. Red mud is treated with lime to convert the silicon phase in solution into hydrogarnet, which is then decomposed by CO2 to recover alumina. In order to simplify the process flow, the direct carbonation process is employed, in which the NaOH-containing solution resulting from calcification is sent directly to carbonation without prior liquid–solid separation. The discrete and direct carbonation processes gave 34.9% and 35.5% alumina recoveries, respectively, with Na2O contents in the final red muds of 0.15%wt and 0.21%wt, respectively. The optimum NaOH concentration in the whole calcification–carbonation process liquor was 40 g/l. Under this alkali condition, alumina recovery reached 40.5% and the Na2O content in the processed red mud was reduced to <1 %wt.

scholarly journals USE OF DUMPED RED MUD OF ALUMINA INDUSTRY AT GRANULATION OF THE MOLTEN SULFUR-CONTAINING BLAST FURNACE SLAG

2019 ◽  
Vol 16 (31) ◽  
pp. 837-845
Author(s):  
Andrey B LEBEDEV ◽  
Vladimir A UTKOV ◽  
Olga A KAYGORODOVA ◽  
Marsel A KADYROV
Keyword(s):  
Blast Furnace ◽  
Red Mud ◽  
Power Plants ◽  
Natural Waters ◽  
Thermal Power ◽  
Alumina Production ◽  
Industrial Gases ◽  
Red Muds ◽  
Alumina Industry ◽  
Sulfur Containing

There is a problem of using waste of alumina production from bauxite red mud. Warehousing of it is fraught with ecological catastrophes. Red muds constantly worsen the environment due to dusting and pollution of natural waters. Red mud is a product of bauxite processing. One ton of alumina accounts for 1 to 2.5 tons of red mud. Currently, it is not being processed, despite the availability of 3,000 publications and patents on this topic. One of them is justified by the ambiguity in the economic effectiveness of its use by consumers. In this paper, the options for economic and environmental efficiency of RM use are presented as substitutes for expensive lime and limestone used for purification of industrial gases emitted to the atmosphere in large quantities with toxic sulfur compounds. Laboratory and industrial tests revealed the sorption properties of red muds. When cleaning gases from sulfur emitted into the atmosphere by furnace gases, thermal power plants, sinter machines, and steelmaking furnaces. In addition, the ecological and technological efficiency of purification of sulfur-containing gases released in the areas of granulation of molten blast-furnace slags is shown.

scholarly journals Limestone Addition Effect on Phase Composition of Red Mud Reduction Roasting Products

2017 ◽  
Vol 2 (2) ◽  
pp. 52
Author(s):  
Mikheenkov M.A. ◽  
Sheshukov O.Yu. ◽  
Lobanov D.A. ◽  
Nerkasov I.V. ◽  
Egiazaryan D.K. ◽  
...  
Keyword(s):  
Phase Composition ◽  
Solid Waste ◽  
Red Mud ◽  
Raw Material ◽  
Pig Iron ◽  
Reduction Roasting ◽  
Protection Measures ◽  
Iron Iron ◽  
Alumina Industry ◽  
Iron Bearing

<p>There are millions of tons of solid waste residues accumulated in present-day alumina industry.  Those solid waste residues contain red mud and belit mud. The creation of sludge depository, its keeping and taking environmental protection measures cost up to $8-12 million a year.  However, red mud is a valuable raw material. The extraction of some useful elements from red mud makes it possible to obtain such valuable products as pig iron, iron-bearing concentrate, rare-earth elements, alumina concrete, constructional materials, etc. </p>

Conversion of Red Muds into Pozzolans

1991 ◽  
Vol 245 ◽  
Author(s):  
Jean Pera
Keyword(s):  
Red Mud ◽  
Mineralogical Composition ◽  
Waste Materials ◽  
Strength Development ◽  
Blended Cements ◽  
Temperature Range ◽  
Lime Consumption ◽  
Red Muds ◽  
Mineralogical Compositions

ABSTRACTRed muds are waste materials obtained from the aluminium extraction industry. They consist mainly of clays, aluminium and iron hydrated oxides. Three muds were studied; they differed in chemical and mineralogical compositions. They were converted into reactive pozzolans by calcination in the temperature range 600–800°C for five hours. Pozzolanicity was investigated on calcined red mud-OPC mixes studying strength development and lime consumption as evaluated by DTA. The nature of hydrates formed during hardening was also identified.The mineralogical composition of the mud is the most important factor affecting its pozzolanicity. Blended cements containing 30% calcined red mud develop significant strengths.

A feasibility study of municipal solid waste incineration fly ash utilisation in Estonia

2017 ◽  
Vol 35 (9) ◽  
pp. 904-912 ◽  
Author(s):  
Hakan Berber ◽  
Ruedi Frey ◽  
Viktoria Voronova ◽  
Arina Koroljova
Keyword(s):  
Environmental Management ◽  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Feasibility Study ◽  
Current Situation ◽  
Environmental Benefits ◽  
Management Options ◽  
Carbonation Process ◽  
Msw Incineration

The purpose of this paper is to discuss the alternative environmental management options for the utilisation of municipal solid waste (MSW) incineration fly ash (FA), which is generated at Iru Power Plant where MSW is incinerated in Estonia. To determine sustainable and economically feasible environmental management options for MSW incineration FA in Estonia, CO2 sequestration with a further carbonation process was examined. A partial Cost & Benefit Analysis has been conducted to compare the carbonation process to the current situation. Two carbonation options were developed. Option 1 is to use carbonated FA in any other processes based on the waste-to-product principle. Option 2 is to send carbonated FA to the non-hazardous landfill in Tallinn, Estonia. Important parameters, such as Net Present Value (NPV), Internal Rate of Return (IRR), Benefit–Cost Ratio (BCR) and Break Even Point (BEP), have been calculated for carbonation options and the current case. In addition, a sensitivity analysis has been conducted to examine its robustness. The results showed that the best option is carbonation Option 1 with NPV of 9,209,662 EUR, IRR of 43%, BCR of 2.63 and BEP between 2018 and 2019. Both Options 1 and 2 constitute more sustainable and environmentally friendly management options compared to the current situation. It can be concluded that this preliminary feasibility study showed that running a carbonation plant may be profitable and sustainable for Estonia. Currently, there is no treatment technology for MSW incineration FA in Estonia and FA is sent to a neighbouring country for further utilisation. This is the first study to demonstrate FA management options with economic and environmental benefits.

Comprehensive Recovery of Iron and Aluminum from Ordinary Bayer Red Mud by Reductive Sintering–Magnetic Separation–Digesting Process

JOM ◽  
2019 ◽  
Vol 71 (9) ◽  
pp. 2936-2943 ◽  
Author(s):  
Feng Gao ◽  
Jihao Zhang ◽  
Xinjie Deng ◽  
Kaituo Wang ◽  
Chunlin He ◽  
...  
Keyword(s):  
Magnetic Separation ◽  
Red Mud ◽  
Bayer Red Mud ◽  
Comprehensive Recovery

The Influence of Amendment to the Red Mud and the Effects of Rehabilitated Red Mud on Sweet Sorghum Seedlings

2014 ◽  
Vol 1073-1076 ◽  
pp. 216-221
Author(s):  
Chong Jian Ma ◽  
Ravi Naidu ◽  
Hui Ming
Keyword(s):  
Red Mud ◽  
Ph Value ◽  
Environmental Concern ◽  
Physical Structure ◽  
Ecological Environment ◽  
In Situ Remediation ◽  
Seedling Root ◽  
Theoretical Significance ◽  
Alumina Industry

Red mud is the waste generated in alumina industry, which occupies much land and brings great harm to the ecological environment and its disposal and comprehensive utilization has become a major environmental concern of the whole society. This thesis discusses the rehabilitating effect of several amendments on red mud and their influences on the growth of the sorgo seedlings, eventually providing theoretical and technical support for in-situ remediation of the ecological environment red mud stacking area. The results show that the amendments could reduce pH value of the soil; the addition of phosphorus, gypsum and sludge can effectively reduce the pH value. All of these are beneficial to soil’s physical structure and seedling root. At the same time, sludge can provide necessary nutrients to seedlings while promote the metabolism. The research results have both theoretical significance and application prospect.

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