Effect of use residual sludge from watertreatment plants as a partial substitute forclay for refractory bricks production

Abstract

The sludge generated from water treatment has been classified as a potential environmental pollutant. Because of its chemical composition similar to clay, was proposed to evaluate the effect of its incorporation as a partial substitute for traditional clay materials in the manufacture of aluminosilicate refractory bricks. The raw materials used were characterized by XRD and XRF; the prototypes designed were mixed, extruded, dried and firing at 1200°C, evaluating their linear shrinkage, apparent density, porosity, water absorption and mechanical and pyroscopic resistance (melting cone softening point). The results show the addition of 10% of sludges from industrial water treatment plant, contributedto elevate the softening point the clay that obtaining a refractory brick capable to supporting a temperature up to 1430 °C

Fabrication of porous mullite‐based ceramic bricks from Al‐rich water treatment sludge and kaolinitic‐based clay

“…The LOI value is close to what was reported in Ref. [21] (8.96%) but very low compared to Sarabia‐Guarín 22 (24.03%). The variation could be due to differences in the amounts of chemicals used for the water treatment.…”

“…A similar observation has been reported where the presence of kaolinite provided low linear contraction and dimensional stability in the production of refractory clay refractory bricks. 22 The mullite bricks produced in the current work are targeted to be used as insulation material in industrial furnaces. As a thermally insulating material, the main properties of interest include density, compressive strength, and thermal conductivity.…”

“…However, high sintering temperatures increase the cost of production. Sarabia-Guarín et al 4 investigated the effect of residual WTS as a partial substitute for clay for refractory bricks production. They found that adding 10% of sludge increased the softening point of the refractory brick and could be used up to 1430 • C. Due to the chemical makeup of WTS, it is possible to produce mullite refractories with a good combination of properties for varied applications by carefully selecting a kaolinitic clay source.…”

“…The relative amounts of these constituents depend on the level of contamination of the raw water, the type and concentration of chemicals used and the efficiency of the treatment process. The chemical composition of the sludge is similar to clay 4 but with high organic matter and high chemicals, which results in high plasticity and low permeability 5 . Due to population growth and increasing demand for potable water, the amount of sludge produced at water treatment plants continues to increase, creating a serious environmental issue.…”

“…However, high sintering temperatures increase the cost of production. Sarabia‐Guarín et al 4 . investigated the effect of residual WTS as a partial substitute for clay for refractory bricks production.…”