Microbial recycling of mineral waste products

Abstract

The applicability of biotechnological methods to metal recovery from non‐sulfide industrial waste products (slag, galvanic sludge, filter‐press residue, filter dust, and fly ash) was investigated. From some products, copper, chromium, zinc or vanadium were completely extracted by sulfuric acid produced by Thiobacillus thiooxidans. The efficiency of bacterial metal solubilization varied depending on the type of waste material and on the pulp density. Stepwise increase of pulp density promoted bacterial growth and activity, resulting in metal concentrations of 6.6 g Cu/l, 6.3 g V/l, 24.4 g Zn/l or 21 g Cr/l in the leaching medium. In some cases bacterial leaching was as effective as chemical leaching with sulfuric acid. The efficiency of both processes is considered. In principal, bacterial metal recovery from industrial waste products seems to be feasible and may contribute to an increase in future supplies of raw materials, as well as to detoxification of industrial waste products resulting in reduced environmental pollution problems.

Bioleaching of metals from printed wire boards by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans and their mixture

“…It is shown that percentages of copper, lead and zinc solubilized decrease with increase of concentration of PWBs in the both cases of 1.0-3.0 and 0.5-1.0 mm of sieve fraction. Especially, when the concentration of PWBs decreases from 7.8 to 19.5 g l −1 , percentages of copper, lead and zinc solubilized decreased considerably for most of the experimental cases, which illustrates that the concentration of PWBs should be controlled under a reasonable range although A. ferrooxidans was reported to be able to tolerate high metal concentrations [34,35].…”

The microbial remediation of former gasworks sites: A review

“…Metals may be amenable to microbial treatment in a number of ways, for example the oxidation of metal sulphides and sulphide containing ore by Thiobacillus ferroxidans is well documented and is commercially operated in the recovery of copper from low grade ores (84). The process has also been applied at a laboratory scale to a variety of other metals including cadmium, copper, nickel and zinc (85,86). The possibility of applying this technology to the treatment of metal contaminated soils has been suggested but does not appear to have been applied to date.…”

Bioleaching: metal solubilization by microorganisms

“…Experiments have shown that the metal oxides in such residues can be leached by acid produced by T. thiooxidans . Depending on the metal compounds in the residues, vanadium, chromium, copper and zinc can be almost completely recovered [58]. In some cases, chemical leaching is easier.…”