Geopolymer Composite Materials from Mining and Agricultural Residues for Engineering Applications: Red Mud and Rice Husk Ash | Chapter 7 | Current Research on Geography, Earth Science and Environment Vol. 3

 

The transformation of raw materials into finished products generates residues and waste, whose management has become an environmental concern. With industrialisation and increasing material complexity, human activities have led to the exponential generation of waste. The more diverse and synthetic the materials involved, the more challenging it becomes to manage waste in ways that fulfil the dual objectives of protecting human health and the environment while conserving natural resources. In the Bayer process, the reaction of bauxite with sodium hydroxide to produce alumina results in the generation of red mud (RM), a highly alkaline waste that occupies land and poses environmental risks. In Guinea, rice is a staple food, and its processing produces large quantities of rice husk (RH), which also presents disposal challenges. RH contains about 20% silica, which becomes approximately 90% silica after combustion, forming rice husk ash (RHA) — a valuable material for various applications. Geopolymer technology offers a sustainable route for the valorisation of industrial residues. This study aimed to develop and analyse geopolymer composite materials using red mud and rice husk ash as alternatives to conventional construction materials. In this study, a composite geopolymer (GP) was synthesised using RM from a local alumina plant, RH from a local rice mill in Guinea, and water glass solution (WGS). For mechanical and microstructural characterisation, the geopolymer specimens were categorised into three main groups—GPA, GPB, and GPC—based on varying RM and RHA ratios while keeping the water glass solution (WGS) constant at 15%. Various mix ratios of RM, RHA, and WGS were tested. The resulting specimens were evaluated for compressive strength at different curing temperatures. Microstructural characterisation was conducted using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The results revealed that the final product is predominantly composed of amorphous geopolymeric phases and that higher temperatures enhance the compressive strength of the material. The XRD of RM is characterised by the presence of sharp peaks mainly caused by hematite (Fe₂O₃), gibbsite (Al(OH)₃), akdalaite (4Al₂O₃·H₂O), lepidocrocite (FeO(OH)), and calcite (CaCO₃). There are no broad humps in the pattern; hence, amorphous phases are not present in large quantities. The greatest value of compressive strength was developed by the GPB1 specimen exhibited a strength:  36,31 MPa at ambient temperature and 66,97 MPa at 1000°C. Through geopolymerization, RM and RH are not stored in piles or dumped into nature; this is a considerable achievement for the circular economy and the zero waste principle.

 

 

Author(s) Details

D. Sidibé
Higher Institute of Mines and Geology of Boké, ISMGB, Guinea.

 

D. Keita
Higher Institute of Mines and Geology of Boké, ISMGB, Guinea.

 

A. A. Konaté
Higher Institute of Mines and Geology of Boké, ISMGB, Guinea.

 

O. B. Kaba
Higher Institute of Mines and Geology of Boké, ISMGB, Guinea.

 

M. Cissé
Higher Institute of Mines and Geology of Boké, ISMGB, Guinea.

 

S. Traoré
Polytechnic Institute, University of Conakry, UGANC, Guinea.

 

Please see the book here :- https://doi.org/10.9734/bpi/crgese/v3/6247

Corrosion Resistance Evaluation of Aluminum 6013 Metal Matrix Composites Reinforced with Red Mud Particulates in Acid Chloride Medium | Chapter 4 | Recent Developments in Chemistry and Biochemistry Research Vol. 1

This study focuses on assessing the corrosion properties of metal matrix composites comprised of red mud particulate and aluminum 6013 alloy, particularly for potential use in automobiles due to their cost-effectiveness and comparable or superior performance. Limited research has been conducted on the environmental behaviour of these alloys. Aluminum 6013 alloys, chosen for their relatively high strength in comparison to zinc alloys with a lower melting point, serve as the matrix alloy in this research. Red mud, known for its ceramic inertness and resistance to acidic mediums, is used as a reinforcement in particle sizes ranging from 50-80 µ. Corrosion rates are determined through experiments in an acid chloride medium using the static weight loss method. The metal matrix composites, prepared according to ASTM standards via the liquid melt metallurgy technique using the vortex method, include variations with 2%, 4%, and 6% by weight of red mud, alongside an unreinforced matrix. Tests are conducted using different concentrations of hydrochloric acid at room temperature, with specimens in the form of 20 mm × 20 mm cylinders. Scanning electron microscopy is employed to examine the microstructures of the specimens. Corrosion rates for all samples are calculated using the formula 534 W/DAT mpy. Results, presented in simulation curves, indicate that the composite exhibits higher corrosion resistance compared to the matrix alloy. However, in each test, both alloy composites show a decrease in corrosion resistance over time, attributed to the physical barrier formed by the red mud particles.

Author(s) Details:

K. N. Chandrashekara,
SJC Institute of Technology, Chikkaballapur, Karnataka, India.

Please see the link here: https://stm.bookpi.org/RDCBR-V1/article/view/13611

Bauxite Mining Industry in Guinea and the Valorization Prospects of the Resulting Residue for Engineering Purposes | Chapter 8 | Novel Perspectives of Engineering Research Vol. 4

 Because of the importance and diversity of its natural riches, Guinea is recognised as a geological disaster. Experts, regardless of the grading system, utilise superlatives to highlight the country's tremendous potential. Guinea has 33 percent of the world's known bauxite reserves, according to several geological surveys. The way a deposit's content is defined is inconsistent, and the ideas and definitions are muddled up in different statistics data. As a result, when evaluating distinct bauxite resources, an expert must be aware of the terminologies in use and change his evaluation accordingly. The large bauxite potential presents a significant chance for the country to become a global leader in the bauxite and aluminium industries, as well as create red mud value-adding prospects. The bauxite potential and local alumina industry in Guinea, as well as the technology utilised to evaluate the resulting red mud, are discussed in this article. Guinea's largest direct contribution to GDP comes from the bauxite and alumina sector.

Author(S) Details

Diaka Sidibé
Institut des Mines et Géologie, Boké, Guinea.

Ahmed A. Konaté
Institut des Mines et Géologie, Boké, Guinea.

Oumar B. Kaba
Institut des Mines et Géologie, Boké, Guinea.

Sékou Traoré
Polytechnic Institute, University of Conakry, UGANC, Guinea.

View Book:- https://stm.bookpi.org/NPER-V4/article/view/5108