SIMULATION IN DWSIM OF A MINING EFFLUENT WASTEWATER TREATMENT PROCESS

• DOI: https://doi.org/10.22533/at.ed.3174252421108

• Palavras-chave: mining; cyanide; water treatment; DWSIM simulator; mining; cyanide; water treatment.

• Keywords: mining; cyanide; water treatment; DWSIM simulator; mining; cyanide; water treatment.

• Abstract:

  In Ecuador, mining responsibility includes social and environmental aspects. Wastewater generated by mining industry operations is the main problem. Medium and large-scale mining drives the country's economic growth. Gold mining uses cyanide (NaCN and KCN) in an environmentally damaging process that causes heavy contamination of soil and water resources due to its high toxicity and ability to accumulate in organisms.  In the province of El Oro, mining activity uses metallurgical methods to extract non-renewable minerals, which has led to significant contamination of rivers with highly toxic substances. They have the potential to generate negative impacts and even destroy habitats.
  Various minerals are received at the beneficiation plant, including iron, nickel, gold, arsenic and hydrogen cyanide in minor proportions.  A solids separator was used in the simulation of the mine effluent wastewater treatment plant to separate the minerals from the mine wastewater. Hydrogen peroxide dosing is applied in the CSTR reactor to promote cyanide oxidation and reduce contamination.  A high agreement with reality will be observed when comparing the results obtained with scientific sources.
  To achieve 99.97% oxidation of CN-, two reactors were used: a continuous stirred tank reactor (CSTR) and a conversion reactor.  A statistical analysis of percentage error was performed, which confirmed the results of the simulation and the literature review.  The simulation performed in the software agrees positively with the experimental data, with a mean absolute percentage error of 0.17%.