Co-Disposal of Coal Gangue and Red Mud for Prevention of Acid Mine Drainage Generation from Self-Heating Gangue Dumps

The seepage and diffusion of acid mine drainage (AMD) generated from self-heating coal gangue tailings caused acid pollution to the surrounding soil and groundwater. Red mud derived from the alumina smelting process has a high alkali content. To explore the feasibility of co-disposal of coal gangue and red mud for prevention of AMD, coal gangue and red mud were sampled from Yangquan (Shanxi Province, China), and dynamic leaching tests were carried out through the automatic temperature-controlled leaching system under the conditions of different temperatures, mass ratios, and storage methods. Our findings indicated that the heating temperature had a significant effect on the release characteristics of acidic pollutants derived from coal gangue, and that the fastest rate of acid production corresponding to temperature was 150 °C. The co-disposal dynamic leaching tests indicated that red mud not only significantly alleviated the release of AMD but also that it had a long-term effect on the treatment of acid pollution. The mass ratio and stacking method were selected to be 12:1 (coal gangue: red mud) and one layer was alternated (coal gangue covered with red mud), respectively, to ensure that the acid-base pollution indices of leachate reached the WHO drinking-water quality for long-term discharge. The results of this study provided a theoretical basis and data support for the industrial field application of solid waste co-treatment.

The Influencing Research for Acid Pollution to Laterite Intensity

The research purpose is the change for acid pollution lateritic shearing strength indices and compressor characteristics indicial under different concentration of hydrochloric acid , differ curing time in text.The test result proven,acid pollution lateritic shearing strength indices and compressor characteristics indices population take on depress tide in company with hydrochloric acid concentration and curing horary Increase.

The Research of Shear Strength and Micro-Structural Characteristics of Acid Pollution Laterite

With hydrochloric acid as the source of pollution, with laterite as the pollution soil, the shear strength and micro-structural characteristics of acid pollution laterite are studied by direct shear test. The results shown that, the shear strength and microstructure characteristics of acid pollution laterite are affected acid concentration and pollution time. The shear strength and indexes of acid pollution laterite decrease in general with the increase of acid concentration and the extension of the specimen pollution time, the shear strength and indexes exist a minimal value at lower concentration and shorter pollution time, the shear strength and indexes exist a great value at higher concentration and longer pollution time, the corresponding microstructure images present to the characteristics of compactness, roughness, color, texture.

The Microstructure Characteristic of Compacted Laterite with Acid Pollution

s. The microstructure characteristic of compacted laterite with acid contamination was researched by means of electronic microscope scanning and microstructures image analysis in which the hydrochloric acid was used as pollutant and the acid concentration and curing history of samples were taken into account. It shows that acid pollution significantly influences the microstructure of laterite in which with more acid concentration and longer pollution times, the microstructure images behave lower compaction, blur particle edges, dissolution cement among particles, gluing coatings parceling particles, pores among particles and darker gray color. The corresponding parameters of the microstructure behave different properties in which with longer pollution times of samples, there is a maximum of porosity, girths of particles increase, number of particles decreases, the circularity of particles is not obvious, the directionality and the fractal dimension vary with magnification of the images and with more acid concentration, the girths and porosity increase, the circularity and fractal dimension decrease, the particle number and the directionality vary with the magnification of images. The result shows that the mechanism of the effect of acid contamination on laterites micro structures is that the acid erodes its particles and the cement among particles.