Estudo do comportamento de diferentes materiais geotécnicos submetidos à ação de lixiviados ácidos

Abstract

The final disposal of waste without the use of technical engineering criteria, has the potential to cause damage to the environment, such as contamination of soil and water sources due to contaminants present in solid industrial and mining waste. The result can be a liquid contaminant of high acidity and high concentration of chemical elements solubilized in acidic solutions. Compacted barriers to contain pollutants are a viable alternative from an economic and environmental perspective. In this context, the present research aimed to evaluate four different materials, fine sand, kaolin, bentonite and residual basalt soil, regarding the ability to withstand the attack of solutions with different concentrations of sulfuric acid. For this, two types of evaluations were foreseen: one in which the solid sample in its pure state is dispersed in an acid solution, called Unstructured test, simulating a batch test; and another where mixtures between different materials are in Structured form, for simulation of consolidation tests. The results generally suggest for Unstructured Studies that in order of resistance to acid attack we have fine sand, kaolin, bentonite and residual basalt soil. For the Structured tests we have the sequence kaolin, mixture (kaolin + bentonite) and bentonite. It can be concluded from the investigation carried out that the samples of kaolin and mixture are suitable for use in contaminated barriers in relation to the mechanical, chemical, geotechnical, morphological and mineralogical aspects analyzed in the study ranging from the concentration 0 mol / L to 0.01 mol / L. Therefore, the concentration range of 0.01 mol / L and 1 mol / L showed consistent changes to changes in all evaluated factors, indicating that from this concentration the safety of the use of the evaluated materials can be compromised.