| Our country is a big country mining production, mining of mineral utilization while promoting economic development in greatly also brought serious environmental pollution problems, which are mainly due to the tailings contain a lot of heavy metal pollutants. Mining is one of smelting waste tailings, and it only takes piling land resources, but also on the surrounding environment pollution caused great damage, leading to mine and the surrounding soil degradation, disruption of normal function of the ecosystem, harm to human health.In this paper, a lead-zinc mine in Shangluo City, Shaanxi Province, more metal contamination tail for the study, chemical leaching of tailings remediation technology research, mainly includes the following two aspects:First, with the removal of heavy metals leaching conditions change One composite eluent tailings leaching of heavy metals Efficiency; the variation and optimum leaching conditions are different eluent. This paper studies the selection of a single eluent leaching effect of heavy metals using various eluent shock leaching method; leaching proved several better-optimum leaching conditions eluent; with Pb, Cd, Cu three metals, for example, explores the complex eluent to heavy metals leaching efficiency, optimum concentration ratio of each composite eluent aimed at removing the multi-metal contaminated tailings for the eluent provide reference for the actual processing.The experimental results show that the experimental tailings taken very serious heavy metal pollution, total Pb, total Zn, and total Cd, total As exceeded environmental quality standards for soil, seven kinds of heavy metals in the study were more than sample point local background value of soil heavy metal content. By BCR morphological analysis shows, Co, Pb bioavailability is high, easy to transport and transformation; high residual content of As and Zn, weak activity, more stable.Different eluent removal efficiency of heavy metals have the larger gap in the six eluent.HCl, HNO3 and EDTA had the best treatment effect, its the amount of heavy metals leaching are significantly higher than other eluent, followed by FeCl3, NH4SO4 solution and CaCl2 solution for the removal of heavy metals in several studies were low. For this leaching experiments, the impact of the eluent concentration of each metal extraction efficiency of the largest, followed by solid-liquid ratio and time, relatively little influence leaching times.Experiment HCl, HNO3, EDTA, FeCl3 several leaching single eluent were better optimized conditions, the overall cost, the amount of eluent, the actual operation and other factors, derived concentration of HCl 0.05mol·L-1 in the solid-liquid ratio of 1:10, leaching time was 6 hours, to carry out a leaching tailings leaching rate can get better; HNO3 0.1mol·L-1, and the solid-liquid ratio of 1:10 leaching time was 12h, a leaching of tailings leaching rate can get better; EDTA 0.05mol·L-1, and the solid-liquid ratio of 1:10, leaching time was 18h, on the tailings a leaching leaching rate can get better; 1.0mol·L-1 FeCl3, the solid-liquid ratio 1:15, leaching time was 12h, rinsed twice for tailings leaching get better rate.Compared with the single eluent, eluent complex leaching leaching efficiency has improved. Higher concentrations of EDTA, FeCl3 and HCl, HNO3 complex after its synergy weaken or even showing antagonism, indicating that the composite eluent elution eluent concentration is not the bigger, the better they will be leaching effect. Comparing the composite eluent removal efficiency of heavy metals in the treatment effect for each of the best heavy metal is HNO3-FeCl3. |
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