scholarly journals An Alternative to Clay in Building Materials: Red Mud Sintering Using Fly Ash via Taguchi’s Methodology

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Suchita Rai ◽  
Dilip H. Lataye ◽  
M. J. Chaddha ◽  
R. S. Mishra ◽  
P. Mahendiran ◽  
...  
Keyword(s):  
Fly Ash ◽  
Construction Industry ◽  
Red Mud ◽  
Morphological Analysis ◽  
Building Materials ◽  
Sintering Temperature ◽  
Bauxite Residue ◽  
Significant Parameter ◽  
Alkaline Waste ◽  
Free Caustic Soda

“Red mud” or “bauxite residue” is a highly alkaline waste generated from alumina refinery with a pH of 10.5–12.5 which poses serious environmental problems. Neutralization or its treatment by sintering in presence of additives is one of the methods for overcoming the caustic problem as it fixes nearly all the leachable free caustic soda present in red mud. In the present study, feasibility of reducing the alkaline nature of red mud by sintering using fly ash as an additive via Taguchi methodology and its use for brick production, as an alternative to clay, is investigated. The analysis of variance (ANOVA) shows that sintering temperature is the most significant parameter in the process. A pH of 8.9 was obtained at 25–50% of red mud and 50–75% fly ash with water and temperature of . Alternatively 50% of red mud can be mixed with 50% of fly ash with water at temperature of to get a pH of about 8.4. The mechanism of this process has been explained with also emphasis on chemical, mineralogical, and morphological analysis of the sintered red mud. The results would be extremely useful in utilization of red mud in building and construction industry.

Effect of Heat Treatment Process on the Preparation of Foamed Glass Ceramic from Red Mud and Fly Ash

2014 ◽  
Vol 670-671 ◽  
pp. 201-204 ◽  
Author(s):  
Yu Xi Guo ◽  
Yi He Zhang ◽  
Hong Wei Huang ◽  
Pan Hu
Keyword(s):  
Heat Treatment ◽  
Fly Ash ◽  
Glass Ceramic ◽  
Red Mud ◽  
Treatment Process ◽  
Sintering Temperature ◽  
Holding Time ◽  
Heat Treatment Process ◽  
Ceramic Foams

Lightweight glass ceramic foams have been prepared from a mixture of solid wastes, namely 40 wt-% red mud and 60 wt-% fly ash. In this work, we illustrate the effects of variables in heat treatment process, including the sintering temperature and the holding time, on the quality of the foams. The reduction of sintering temperature as well as the holding time, was found to limit the coalescence and improve the apparent density and the compressive strength.

scholarly journals Radiological and physico-chemical characterization of red mud as an Al-containing precursor in inorganic binders for the building industry

2021 ◽  
Vol 36 (2) ◽  
pp. 182-191
Author(s):  
Ljiljana Kljajevic ◽  
Miljana Mirkovic ◽  
Sabina Dolenec ◽  
Katarina Ster ◽  
Mustafa Hadzalic ◽  
...  
Keyword(s):  
Construction Industry ◽  
Natural Radioactivity ◽  
Red Mud ◽  
Building Materials ◽  
Raw Materials ◽  
Construction Materials ◽  
Polymerization Process ◽  
Alkali Activation ◽  
Silica Alumina ◽  
Alkali Activated

The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milici, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials.

Study on Light Porous Unsintered Building Material

2012 ◽  
Vol 532-533 ◽  
pp. 144-148
Author(s):  
Cong Cong Jiang ◽  
Gou Zhong Li ◽  
Qi Jin Li
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Red Mud ◽  
Building Material ◽  
Building Materials ◽  
Thermal Conductivity Coefficient ◽  
Raw Materials ◽  
Ambient Conditions ◽  
Optimum Ratio ◽  
Broad Application

A light porous unsintered building material was prepared with red mud, fly ash, silica fume as the main raw materials, mixed with a certain amount of foam and curing agent, by the technology of casting and curing at ambient conditions. The influence of different ratio of red mud to fly ash on compressive strength was studied. The microstructure properties of light porous unsintered building material were characterized by scanning electron microscopy (SEM) and then the strength mechanism was studied. The results showed that the optimum ratio of red mud to fly ash was 2:1, and for the best sample, its bulk density was 891kg•m-3, 7d and 28d compressive strength were 8.4MPa and 14.7MPa, thermal conductivity coefficient was 0.235W•(m•K)-1, which may have a broad application prospect in the building materials field.

Heat Preservation Time on the Properties of Red Mud Lightweight Insulation Brick

2014 ◽  
Vol 540 ◽  
pp. 225-228 ◽  
Author(s):  
Long Ma ◽  
Guo Zhong Li ◽  
Ji Rui Hu
Keyword(s):  
Electron Microscope ◽  
Fly Ash ◽  
Scanning Electron Microscope ◽  
Red Mud ◽  
Sintering Temperature ◽  
Raw Material ◽  
Sintering Process ◽  
Heat Preservation ◽  
Fluxing Agent ◽  
Scanning Electron

The red mud lightweight insulation brick was prepared by the sintering process as red mud, fly ash, bentonite as the main raw material, adding a certain amount of pore forming agent and fluxing agent. The sintering heat preservation time of red mud insulation brick on the properties was studied. The red mud lightweight insulation brick damage fracture microstructure was analyzed using scanning electron microscope (SEM) and the sintering mechanism was discussed preliminarily. The results show that with sintering temperature of 1100°C heating for 180 minutes, the performance of thermal insulation brick is better. When the heat preservation time extends to continue, the performances of sample remain stable basically.

scholarly journals Progress on the Industrial Applications of Red Mud with a Focus on China

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 773
Author(s):  
Hua Zeng ◽  
Fei Lyu ◽  
Wei Sun ◽  
Hai Zhang ◽  
Li Wang ◽  
...  
Keyword(s):  
Red Mud ◽  
Building Materials ◽  
Bauxite Residue ◽  
Industrial Applications ◽  
Utilization Rate ◽  
Oil Well ◽  
Alumina Production ◽  
Industrial Utilization ◽  
Develop Technology ◽  
Well Cement

Red mud (RM), also called bauxite residue, is a strong alkaline industrial waste generated during the alumina production process. The annual production of RM in China is large, but its average utilization rate is low (only 4%). High generation and low consumption make the disposal of RM mainly by stockpiling, which has caused serious heavy metal pollution and radioactive contamination. In this paper, the various industrial utilization methods of RM in China during the past 60 years have been introduced. Moreover, some recent industrial progresses were referred. The results show that RM can be widely used in building materials, valuable metals extraction, and some novel utilization methods, such as silica-calcium fertilizer, inorganic polymer material and desulfurizer. Most of the industrial utilization methods of RM have been used until now and some successfully applied to other aluminum plants, providing some feasible routes for a large amount utilization of RM. Some industrial utilization methods (such as oil well cement and calcium silicon fertilizer) have not been used due to some problems that cannot be ignored, but it provided a lot of valuable experience and was helpful for the subsequent RM utilization. Moreover, some novel and feasible RM utilization methods were proposed and successfully industrialized, which showed that RM has a broader application prospect. Many actual practices showed that the best way to safely dispose of RM was to develop technology that could consume large amounts of RM or transform it into secondary resources, which may need more time and effort.

scholarly journals Implementation of two-phase flow models for recycled materials in embankments

2021 ◽  
Vol 337 ◽  
pp. 03002
Author(s):  
João A.R. Machado ◽  
Ambria Vasquez ◽  
Wing Shun Kwan ◽  
Jose M. Fuentes ◽  
Gustavo Menezes
Keyword(s):  
Fly Ash ◽  
Red Mud ◽  
Power Plants ◽  
Unsaturated Flow ◽  
Bauxite Residue ◽  
Feasibility Studies ◽  
Analytical Models ◽  
Soil Water Retention ◽  
Two Phase ◽  
Recycled Materials

Recycled materials like Bauxite Residue (Red Mud) and Fly Ash are prevalent in recent feasibility studies on reused materials in geotechnical engineering applications. Red Mud is a mining waste from aluminum manufacturing, and Fly Ash is a by-product of coal combustion in power plants. Nevertheless, to fully reveal the feasibility of using those materials for constructing above-ground earth structures, a better understanding of their unsaturated performance in geo-structure is essential. While some popular empirical models (e.g., van Genuchten 1980) in Soil Water Retention Curves (SWRC) are commonly used to describe soils' unsaturated conditions, those models may not apply to unique materials like Red Mud and Fly Ash. Recently, SWRC curves of both materials were acquired through the Steady-State Centrifuge (SSC) Unsaturated Flow Apparatus (UFA) procedure at Cal State LA. The experimental data were used to develop analytical models following the van Genuchten model. Using a finite-difference software (FLAC) and obtained SWRC curves, this study performed numerical simulations of embankments filled with Fly Ash and Red Mud, comparing it with an embankment filled with typical silty soil with the same dimensions and conditions. Results showed seepage flow rates for Fly Ash and Red Mud are higher when used as fill material as above-ground embankments.

scholarly journals Radiological and physico-chemical characterization of red mud as an Al-containing precursor in inorganic binders for the building industry

2021 ◽  
Vol 36 (2) ◽  
pp. 182-191
Author(s):  
Ljiljana Kljajevic ◽  
Miljana Mirkovic ◽  
Sabina Dolenec ◽  
Katarina Ster ◽  
Mustafa Hadzalic ◽  
...  
Keyword(s):  
Construction Industry ◽  
Natural Radioactivity ◽  
Red Mud ◽  
Building Materials ◽  
Raw Materials ◽  
Construction Materials ◽  
Polymerization Process ◽  
Alkali Activation ◽  
Silica Alumina ◽  
Alkali Activated

The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milici, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials.

Study on Preparation of Ceramic Material and its Properties

2014 ◽  
Vol 686 ◽  
pp. 57-60
Author(s):  
Ya Li Liu
Keyword(s):  
Fly Ash ◽  
Red Mud ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Porous Ceramic ◽  
High Strength ◽  
Porous Ceramics ◽  
Raw Material ◽  
High Porosity

This paper introduces the classification, properties and application of porous ceramic materials, reviewed preparation of porous ceramics. Taking fly ash and red mud as the main raw material to generate porous ceramics, the paper study the influence of different proportions of raw materials, sintering temperature, porosity of porous ceramic sample rate, bending strength, and microstructure. The results show that, fly ash and red mud proportioning and sintering temperature are the main factors that influence the structure and properties of samples. The 4# sample is a kind of high porosity and high strength quality of porous ceramics.

Leaching Behavior and Immobilization of Heavy Metals in Geopolymer Synthesized from Red Mud and Fly Ash

2018 ◽  
Vol 777 ◽  
pp. 518-522 ◽  
Author(s):  
Hoc Thang Nguyen ◽  
Thu Ha Bui ◽  
Vo Thi Ha Quyen Pham ◽  
Minch Quang Do ◽  
Minh Duc Hoang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Red Mud ◽  
Industrial Waste ◽  
Power Plants ◽  
Building Materials ◽  
Negative Impact ◽  
Raw Materials ◽  
Thermal Power ◽  
Aluminum Production

Fly ash is an industrial waste from coal-fired thermal power plants whereas red mud is an industrial waste generated during aluminum production from bauxite. If both fly ash and red mud are not properly managed, they could cause negative impact on the environment. This study utilized red mud and fly ash in combination with sodium silicate solution to produce a geopolymer-based material which can be used as building materials. This study focussed on the leachability of heavy metals in the raw materials and the geopolymer as this would be significant in assessing the environmental impact of the product. Leachability of heavy metals such as Cu, Zn, Cd, Pb, Fe, and Cr was evaluated based on European standard (EN 124572 – 2, EU CEN TC292/ CEN TC 308) with pH values at 7. The results showed that raw materials (red mud and fly ash) have higher leachability than geopolymer specimens. And the values of leaching tests for heavy metals in the geopolymer - based materials belonged to limits of EULFD and USEPA.

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