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2 Physicochemical Problems of Mineral Processing

2 2019

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Optimization and kinetics studies of lead concentrate leaching using fluoroboric acid

Sabouti Arash, Rezai Bahram, Hoseinian Fatemeh Sadat, Moradkhani Davood

Physicochemical Problems of Mineral Processing

2019

Vol. 55, iss. 4

1014--1027

In this study, the feasibility of lead dissolution from lead concentrate using fluoroboric acid by hydrometallurgical method was investigated in order to aviod the disadvantages of the pyrometallurgical processes. The effects of important operating parameters such as leaching time, liquid/solid ratio, stirring speed, temperature and fluoroboric acid concentration on the lead recovery were investigated using response surface methodology (RSM) based on the central composite design (CCD) model. The results show that the optimum conditions for the high lead recovery were: leaching time= 30 min, liquid/solid ratio= 10, stirring rate= 500 rpm, temperature= 80oC and fluoroboric acid concentration= 3.35 mol/L. More than 94% of lead was recovered in the optimum conditions. The results indicated that the liquid/solid ratio, fluoroboric acid concentration, temperature and leaching time were the most effective parameters on the process efficiency, respectively. Dissolution kinetics studies of lead in the fluoroboric acid were also evaluated. The chemical reaction was determined as the controlling mechanism of reaction at the shrinking core model. The activation energy was determined using Arrhenius model as 5.99 kJ/mol.

Facilitated transport of germanium from acidic medium through supported liquid membrane using Cyanex 301 as mobile carrier

Kamran Haghighi Hossein, Irannajad Mehdi, Moradkhani Davood

Physicochemical Problems of Mineral Processing

2019

Vol. 55, iss. 1

225--236

In this research, a flat sheet supported liquid membrane (FSSLM) system was used to transfer germanium from the acidic medium. The poly-tetra fluoro ethylene (PTFE) membrane filter with the hydrophobic nature and Cyanex 301 were selected as the support and the mobile carrier, respectively. The influence of various parameters being pH of the feed solution (1.5-5), germanium concentration (10-40 mg/dm3), carrier concentration in the solid membrane (10-40 vol%), and sulfuric acid concentration of the receiving phase (100-400 g/dm3) was investigated on the transport of germanium. Under the optimum condition being pH of 1.5, the germanium concentration of 40 mg/dm3, the carrier concentration of 1.18 mol/dm3, and the sulfuric acid concentration of 400 g/dm3, a mass transfer model was developed. Based on this model, the transport mechanism, diffusion of species to the feed-membrane interface, the chemical reaction of species and Cyanex 301, and diffusion of germanium-Cyanex 301 complexes across SLM were explained. According to the obtained model, the values of 6.57 and 738.6 s/cm were achieved for the aqueous and organic diffusion resistances, respectively.