Osvaldo Pavez

Effect of type cement on the mechanical strength of copper slag mortars

A escoria de cobre e um residuo metalurgico massivo e reconhecido como um passivo ambiental. A geracao anual de escoria de cobre e de 24,6 milhoes de toneladas, aproximadamente, e os principais impactos ambientais, derivados da disposicao da escoria, e o uso de grandes extensoes de solo e a contaminacao visual da paisagem. Nas ultimas decadas, as escorias de cobre tem sido utilizadas na fabricacao de concretos e argamassas de cimento. Nesse estudo, com o objetivo de verificar a influencia do tipo de ligante na dureza final de argamassas, foram utilizados dois tipos de cimento: cimento normal e cimento de alta resistencia. A escoria de cobre foi caracterizada por analise quimica, mineralogica e granulometrica. Regras chilenas de construcao foram utilizadas na metodologia aplicada para a determinacao de alguns parâmetros importantes das escorias. Ensaios de resistencia a compressao e flexao foram realizados em argamassas de cimento, em laboratorios especializados. Os resultados obtidos mostraram que as argamassas preparadas com escoria de cobre e cimento normal apresentaram melhor resistencia a compressao e flexao do que as argamassas preparadas com a areia normal, e os resultados obtidos com cimento de alta resistencia inicial foram ainda melhores. Pode-se concluir, a partir desse trabalho, que a escoria de cobre tem boas caracteristicas mecânicas, para ser usada na fabricacao de argamassas de cimento, constituindo-se em uma adequada alternativa para uso na industria da construcao.

Use of copper slag in cement mortar

The use of a Chilean copper smelter slag in the manufacture of cement mortars was studied. Copper slag was characterized from the chemical, mineralogical and size distribution point of view. In addition, different Chilean standards were used to determine some important parameters of the waste and to perform compression and flexural assays of the cement mortars. The results obtained showed that the mortars manufactured with copper slag present a higher resistance to compression and flexural than those manufactured with river sand. It is concluded that this metallurgical residue can be used in civil construction.

Metallurgical characterization of kaolin from Atacama, Chile

In order to determine the exploitation potentiality of a kaolin deposit from Atacama in the north of Chile, two types of kaolin (K-1 and K-2) were characterized by XRD, XRF, SEM/EDXS, size distribution, whiteness and DSC. Kaolinite, quartz, muscovite and albite were recognized as main constituents of the ore deposit, and also a significant amount of impurities that negatively impacts on quality were detected. Results show that the low quality presented by the samples, especially K-2, impedes their industrial use as raw material and further mineral concentration processes are proposed. Finally, the results of thermal analysis confirm a conversion to metakaolin that could be the basis for an alternative processing route.

Copper tailings in stucco mortars

This investigation addressed the evaluation of the use of copper tailings in the construction industry in order to reduce the impact on the environment. The evaluation was performed by a technical comparison between stucco mortars prepared with crushed conventional sand and with copper tailings sand. The best results were achieved with the stucco mortars containing tailings. The tailings presented a fine particles size distribution curve different from that suggested by the standard. The values of compressive strength, retentivity, and adherence in the stucco mortars prepared with copper tailings were much higher than those obtained with crushed sand. According to the results from this study, it can be concluded that the preparation of stucco mortars using copper tailings replacing conventional sand is a technically feasible alternative for the construction industry, presenting the benefit of mitigating the impact of disposal to the environment.