Mixed sulphide–oxide lead and zinc ores: Problems and solutions
Highlights
► We describe the specific problems associated with mixed sulphide–oxide lead and zinc ores. ► We discuss methods for solving problems of mixed sulphide–oxide lead and zinc ores. ► We give results of direct leaching of the Angouran mixed ores using sulphuric acid without oxidising agents. ► We show how factors interact and drive the process. We analyse the optimal levels of variables.
Introduction
The minerals of lead and zinc are naturally associated with each other. Three types of mineralization may be distinguished for every lead and zinc deposit: (i) Sulphide minerals, which are mainly found in the hypogene primary sulphide ore body and mineralization occurs during several successive stages, with lead and zinc being derived from this ore body. Sphalerite (ZnS) and galena (PbS) are the major sulphide minerals of zinc and lead, respectively. (ii) Nonsulphide ores, which fall into two types, hypogene or supergene weathering. The primary sulphide ore body is usually sheltered from supergene weathering by the cap of hypogene oxidised ores. Supergene oxidation ores are evidenced by the absence of sulphide minerals and their outcropping at the surface, or their near surface occurrence. (iii) Mixed sulphide–oxide ores with very complex mineralogy that are most often found in the transition, and occasionally in the oxidised, zones of deposits (Gilg et al., 2006).
In many parts of the world, significant deposits of these mixed sulphide–oxide lead and zinc ores are found with the main sulphide and/or oxidised ore bodies. Because of their complex mineralogy, these ores are very difficult to deal with from a mineral processing point of view and they are very often left untreated as a result of the metallurgical difficulties encountered in extracting lead and zinc from them. Although the primary sources of the metals are lead and zinc concentrates from sulphide and oxidised ores, as supplies of these deplete, the processing of mixed ores must be considered. Iran, which is a country rich in lead and zinc minerals, is a case in point. In Iran, mixed sulphide–oxide lead and zinc ores comprise about 10% of all the country’s lead and zinc resources. There is great potential to exploit many well-scattered small reserves of mixed ores. There are also numerous stockpiles, tailing ponds and buried mine tailings of mixed ores that are important enough to receive attention. To date no research on the hydrometallurgical processing of mixed sulphide–oxide lead and zinc ores appears to have been done, despite an obvious need among the lead and zinc industries in the world. This work was an attempt to fill that gap.
Section snippets
Literature review
Conventionally, mixed ores were treated by pre-concentration and differential froth flotation (Bulatovic, 2010), followed by smelting for the recovery of lead (Hofman, 1918) and the roast/calcine–leach–electrowin process for recovery of zinc (Sinclair, 2005). A block diagram illustrating the conventional treatment of mixed ores is shown in Fig. 1.
The following list outlines the problems experienced in the use of the conventional approach:
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Differential froth flotation is very difficult because of
Materials
All mixed sulphide–oxide lead and zinc ore materials being studied in this work are representative natural samples from the gigantic transition zone of the Angouran mine in Iran. The world-class Angouran mine is the largest lead and zinc mine in the Middle East. It is situated in the north west of Iran and it has been the focus of many investigations by world-famous zinc companies. The Pb/Zn resources in the transition ores in this mine are not presently being exploited.
Sample characteristics and discussion
A variety of lead and
Results and discussion
The first set of leaching experiments was conducted to screen the effect of five variables, i.e., acidity, temperature, pulp density, stirring rate and particle size on the rate of zinc extraction to determine which were important for explaining process reactions and to understand how factors interact and drive the process. For these, a two-level, fractional factorial design of experiments with the design resolution of V (higher) was employed. The constraints on the design space are given in
Conclusions
Mixed sulphide–oxide lead and zinc ores are characterized by a very complex mineralogy, which presents economic and technical difficulties for the conventional mineral processing route. A variety of lead and zinc minerals (sulphide, silicate, carbonate, arsenate and chloro-arsenate) existed in the Angouran mixed high-grade ore sample that was used for this study. The percentage of the zinc in the oxidised part of sample was 70.5%. This emphasized the importance of the oxidised part of the
Acknowledgements
SM is grateful for financial support from the Institute of Materials, Minerals and Mining, in the form of a Stanley Elmore bursary, which enabled this research to be carried out.
References (229)
Kinetics of sulfuric acid leaching of low-grade zinc silicate ore
Hydrometallurgy
(2000)- et al.
Effect of dissolved mineral species on the electrokinetic behaviour of sulfides
Minerals Engineering
(1992) - et al.
Grinding media wear and its effect on the flotation of sulfide minerals
International Journal of Mineral Processing
(1984) Electrochemical studies of sulphides, ii. Measurement of the galvanic currents in galena and the general mechanism of oxygen reduction and xanthate adsorption on sulphides in relation to flotation
International Journal of Mineral Processing
(1978)- et al.
Effect of grinding media-chalcopyrite interaction on the self-induced flotation of chalcopyrite
International Journal of Mineral Processing
(1991) - et al.
Metals recovery from multimetal sulphide concentrates (CuFeS2–PbS–ZnS): combination of thermal process and pressure leaching
International Journal of Mineral Processing
(2003) - et al.
Rate of cadmium ions removal from dilute solutions by cementation on zinc using a rotating fixed bed reactor
Hydrometallurgy
(2007) - et al.
Leaching of lead sulphate in sodium carbonate solution
Hydrometallurgy
(1984) - et al.
Effects of galvanic interactions of sulfides on extraction of precious metals from refractory complex sulfides by bioleaching
International Journal of Mineral Processing
(1990) Dissolution kinetics of sphalerite with hydrogen peroxide in sulphuric acid medium
Chemical Engineering Journal
(2006)
Kinetics of galena dissolution in nitric acid solution with hydrogen peroxide
Hydrometallurgy
Zinc recovery from sphalerite concentrate by direct oxidative leaching with ammonium, sodium and potassium persulphates
Hydrometallurgy
Influence of solid state properties on ferric chloride leaching of mechanically activated galena
Hydrometallurgy
Mineral properties and bacterial leaching of intensively ground sphalerite and sphalerite-pyrite mixture
International Journal of Mineral Processing
Assessment of alternative iron sources in the pressure leaching of zinc concentrates using a reactor model
Hydrometallurgy
The passivation of chalcopyrite subjected to ferric sulfate leaching and its reactivation with metal sulfides
Hydrometallurgy
A study on the dissolution of lead sulphate from waste batteries with Ethanolamines
Hydrometallurgy
Kinetics of dissolution of lead sulphate from waste battery scrap by aqueous Triethanolamine solution
Hydrometallurgy
Galvanic interaction between chalcopyrite and pyrite during bacterial leaching of low-grade waste
Hydrometallurgy
Hydrometallurgical treatment of zinc silicate ore from Thailand
Hydrometallurgy
Improvements in pressure leaching at Kidd Creek
Hydrometallurgy
Fundamental study of silver deportment during the pressure oxidation of sulphide ores and concentrates
Minerals Engineering
The oxidation kinetics of zinc sulphide with Thiobacillus ferrooxidans
Hydrometallurgy
The treatment of bulk concentrates by the sherritt zinc pressure leach process
Minerals Engineering
Chloride leaching of Portuguese lead concentrates
Minerals Engineering
Thermodynamic and kinetic study of the pressure leaching of zinc sulfide in aqueous sulfuric acid
Hydrometallurgy
Kinetics and mechanism of the oxidative dissolution of a zinc sulphide concentrate in ferric sulphate solutions
Hydrometallurgy
Refractory behaviour of two sphalerite concentrates to dissolution in ferric sulphate solutions
Technical note. Hydrometallurgy
An experimental strategy to determine galvanic interactions affecting the reactivity of sulfide mineral concentrates
Hydrometallurgy
Statistical evaluation and optimization of factors affecting the leaching performance of a sphalerite concentrate
International Journal of Mineral Processing
Modified Zincex process: the clean, safe and profitable solution to the zinc secondaries treatment
Resources, Conservation and Recycling
Mass transfer correlation of removal of nickel by cementation onto rotating zinc disc in industrial zinc sulfate solutions
Minerals Engineering
Iron removal during oxidative, acid pressure leaching of a zinc sulphide concentrate
International Journal of Mineral Processing
The oxidation of ferrous sulphate by molecular oxygen under zinc pressure-leach conditions
Hydrometallurgy
Recovery of silver and zinc by acid pressure oxidative leaching of silver-bearing low-grade complex sulfide ores
International Journal Mineral Processing
Alkaline leaching of zinc from electric arc furnace steel dust
Minerals Engineering
The leaching of sulphide minerals in chloride media
Hydrometallurgy
Effects of galvanic interaction on collectorless flotation behaviour of chalcopyrite and pyrite
International Journal of Mineral Processing
Influence of galvanic interactions between chalcocite and sphalerite during the early stage of leaching
Minerals Engineering
Hydrometallurgical treatment of tailings with high zinc content
Hydrometallurgy
Brine leaching of lead bearing zinc plant residues: process optimization using orthogonal array design methodology
Hydrometallurgy
Optimization and kinetics of the cementation of lead with aluminum powder
Hydrometallurgy
Leaching of oxidized zinc ore in various media
Hydrometallurgy
SEM and AES studies of a lead sulphide bioleaching in presence of catalytic ions
Minerals Engineering
Kinetics of conversion of galena into lead carbonate in ammonium carbonate solution in the presence of cupric ion
Hydrometallurgy
The conversion of lead sulphate to lead carbonate in sodium carbonate media
Hydrometallurgy
The reaction of anglesite (PbSO4) crystals with sodium carbonate solutions
Hydrometallurgy
Diagnostic leaching of galena and its oxidation products with EDTA
Minerals Engineering
Optimization of brine leaching of metals from hydrometallurgical residue
Transactions of Nonferrous Metals Society of China
Formation of copper (I) sulphate during cupric chloride leaching of a complex Cu/Zn/Pb ore
Hydrometallurgy
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