Application of bauxite waste from amazon region in the heavy clay industry

Abstract

In this work, a method was developed for the application of red mud, an alkaline leaching waste, from a bauxite processing plant located in northern Brazil (Amazon region) as starting material for heavy clay products. Samples were prepared by pressing blends of red mud and clay, which were then fired at temperatures from 900 °C to 1190 °C. Characterization was carried out by chemical analysis, differential thermal analysis (DTA) and X-ray diffraction (XRD), and the following ceramic properties were evaluated: water absorption, linear shrinkage and flexural strength. In order to evaluate the Na + stability in the dense ceramic, leaching tests were also carried out on the specimens after sintering process. Results indicated that samples with 50 and 70 wt% of red mud are proper for being used in the production of ceramic bodies, due to its excellent properties, mainly high mechanical resistance and low water absorption, showing thus, an option to minimizing the environmental impacts caused by the aluminum industry.

Sterile Clay Pozzolans from Phosphate Mining

“…In the sample diffractograms, the presence of several peaks of crystalline materials is observed, such as kaolinite, goethite, anatase, apatite, and gibbsite. These results are consistent with those reported in the application study of red mud residue from bauxite processing for use as raw material in clay-based products 6 . The spectra are consistent with the results presented in the X-ray Fluorescence Spectroscopy test that shows the prevalence of elements such as Al, Fe, Si, Ti, and P.…”

Analysis of the Spheres and Bars Molded with Blast Furnace Sludge Incorporation in Clayey Mass

“…The concentration of (Na 2 O+K 2 O<1.25%) is not high; hence, even being fluxing oxides; they contribute little to the formation of the glassy phase. Clay with these characteristics (silica aluminous, with high iron content and low content of fluxing oxides) observed in XRD demand high sintering temperature, as reported by Hildebrand et al [16] . As seen in the table, blast furnace sludge presents a high concentration of iron oxide (61.2%) and high content of loss on ignition (25.9%) when compared to clay, corroborating the information in Vieira et al [2] this value corresponds to the combustion of coke fines present in the sludge.…”

Utilization of water treatment plant sludge in structural ceramics bricks

“…This type of curves is also known as gresification diagram, which is associated with the efficiency of the sintering process. The sintering of a material usually causes many changes in its properties (Edemarino Araujo Hildebrando et al, 2013).…”