Review of trace toxic elements (Pb, Cd, Hg, As, Sb, Bi, Se, Te) and their deportment in gold processing. Part 1: Mineralogy, aqueous chemistry and toxicity

Abstract

with further research based on gaps in the current knowledge of the thermodynamics and kinetics of these systems, will support the development of computer models to predict the chemical speciation and deportment of these elements through the various stages of the gold cyanidation process. The review covers lead, cadmium, mercury, arsenic, antimony, bismuth, selenium, and tellurium. Presented in this paper is the first part of this review which is a collation of the relevant information on trace element mineralogy, aqueous solution chemistry and toxicity.Although there is much information available about the aqueous solution chemistry of the trace elements, their chemistry in cyanide leach solutions remains largely unexplored. Chemical speciation modelling can assist in understanding the chemistry of the trace elements in gold cyanidation solutions, however, many significant differences exist between the predicted speciation of these trace elements for different types of modelling software. This is due to differences in the thermodynamic data used, the paucity of data that exists under appropriate non-ideal conditions, and the methods used by the software packages to estimate thermodynamic parameters under these conditions.The trace elements reviewed, particularly the species that exist in aqueous solutions, generally have significant toxicities to humans, and more so to plants and animals.Cadmium, mercury and arsenic are classified as human carcinogens whereas selenium is an essential trace element for human health, but is toxic in excess. This review

Constraints on the solid solubility of Hg, Tl, and Cd in arsenian pyrite

“…For example, 810 Mt/year of Hg are released into the atmosphere as a result of coal combustion (Pirrone et al 2010), and industrial processing is responsible for the mobilization of 2000-5000 t/year of Tl (Kazantzis 2000;John Peter and Viraraghavan 2005). Furthermore, recent studies have estimated the emission of 4.7 t/year of Cd from sulfide ore mining and 10 t/year in air from basic non-ferrous metals manufacture in Australia (Kyle et al 2011). In the particular case of As, there are numerous studies reporting natural and anthropogenic contamination of water and soil, and its effects on human health (Plant et al 2014).…”

“…Among the numerous toxicological effects of As and heavy metals (Tl, Hg, and Cd) on biota, carcinogenic, and brain dysfunction effects are considered some of the most important for human life (Kyle et al 2011 and references therein).…”

Arsenic toxicity in Acacia mangium willd. and mimosa Caesalpiniaefolia benth. seedlings

“…The major natural pathways for As accumulation are mineral weathering and volcanic eruptions, whereas mining, ore smelting, agrochemicals and wood preservatives are important anthropogenic sources (Mandal & Suzuki, 2002;Kyle et al, 2011). Arsenic is toxic to living organisms, since it disrupts many metabolic processes, but its toxicity level depends on the (organic or inorganic) origin and oxidation state (Kyle et al, 2011). Usually, in a less oxidized state, as in As(III) (arsenite), arsenic is more toxic and the organic As forms are less toxic than their organic counterparts (Litter et al, 2008).…”

Chemical and Mineralogy Characteristics of Dust Collected Near the Phosphate Mining Basin of Gafsa (South-Western of Tunisia)

“…A high concentration of Cd in S1and S2 may be due to phosphate activities because Cd can be found in phosphate rocks as can be seen in Table 8 [19].…”