Editors: | F. Kongoli, G. N. Anastassakis, A. Abhilash, H. R. Kota, A. G. Merma, E. Souza, C.H. Sampaio, R. Souza, M.M. Vellasco, F. Zeballos, J. Sokolovic |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2023 |
Pages: | 142 pages |
ISBN: | 978-1-989820-90-2 (CD) |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Sodium cyanide (NaCN) is a solubilizer that improves gold uptake in phytomining [1]. However, concerns have been expressed about the persistence of this adjuvant and their associated detrimental repercussions for environment. Therefore, evaluating the persistence of residual CN in the remained substrates is relevant [2]. In order to assess the loss of CN in a gold phytoextraction process with Helianthus annuus L. (sunflower) on a gold mining waste. Pots containing 3.5 kg of substrate were prepared for this study. Sunflower plants were cultivated in a homemade greenhouse. Temperature range was 24-38° C and environment humidity range was of 40-60%. Twelve weeks after seeding, all containers were treated with a dose of 250 mg.kg-1 of NaCN in solution. Seven days later, plants were harvested. Samples with 30 g of substrate were obtained in all containers at time of plant harvest 7, 14, 21, 28, 35, and 42 days after harvest. Samples were prepared and analyzed in laboratory to determine the total content of CN. We found that 7 days after the application, the CN total concentration was reduced in a 91.7% for containers without plants and 90.8%, for containers with plants, respectively. Plants cultivated in mine waste produces a small increase in loss of adjuvant[3]. These results suggest that concerns about CN could be reduced, because it is enough one week of natural intemperization processes, to reduce significantly the CN in soil. This study could be applied to the mining waste management and the environmental impact of CN application in the gold mining industry.