Remoción de metales pesados de los drenajes de la mina ecuaba concesión minera el guayabo mediante neutralización y precipitación química

Abstract

Water resources are of great economic, social and environmental importance for communities. However, in recent decades we have witnessed a progressive deterioration in the quality of water resources, covering physical, chemical and microbiological aspects. This phenomenon poses significant challenges. The importance of heavy metal removal at the mine mouth of the El Guayabo Code 225 mining concession is due to the fact that it is a tributary to the El Panteón stream, which is located in the Torata parish within the Santa Rosa canton, which directly affects the health of local residents, as well as the biodiversity and surrounding vegetation. The purpose of this experimental work is to remove the heavy metals present in the drainage of the Ecuaba mine in the mining concession El Guayabo code 225, by means of neutralisation and chemical precipitation, in order to comply with the criteria established in Annex 1 of the unified text of secondary legislation of the Ministry of Environment: Norma de Calidad Ambiental y de Descarga de Efluentes al recurso agua. For which various aspects have been taken into account, such as the selection of the sampling points, the parameters with which they will be analysed, the frequency of sampling, and the sampling method. In addition to observing the anthropogenic activities, the samples were collected in a 3 L container, in which they were divided into 5 samples of 500 mL. The process was carried out by titration by adding 0,1 N sodium hydroxide solution, until obtaining pH 4,5,6,7,8 respectively for each sample. The results obtained in the initial sample showed a pH concentration of 2,62, which is an acid pH, and an electrical conductivity of 2,23 mS/cm. In the analysis of heavy metals, 5 mg/L Cu; 0,05 mg/L Cr; + 5 mg/L Iron; 0,0261 mg/L Pb, and 1,0869 mg/L As. For the other samples, precipitation and neutralisation with sodium hydroxide was carried out, in which a progressive variation of pH concentration was obtained, from pH 4 to 8, from sample N°1 to N°5. In this way, it was possible to obtain a progressive reduction in the physico-chemical analysis and in the concentration of heavy metals. It was shown by means of physicochemical analysis and heavy metal measurement that there was a significant reduction in heavy metal concentrations, which comply with Annex 1 of the TULSMA. A concentration of Cu of 0,14 mg/L, Cr of 0,002, Fe of 0,32 mg/L, and Pb was completely removed in the precipitation. As only decreased its concentration to 0,3636 mg/L, so the concentration does not meet the quality criteria of Annex 1 of the TULSMA.