Kinetics improvement of high-grade sulphides bioleaching by effects separation

Abstract

The kinetics of bioleaching of sulphide concentrates by Thiobacillus ferrooxidans can be improved by performing separately the two operations relating the two effects involved in the indirect contact mechanism, (1) chemical leaching and (2) biological oxidation of the Fe2+ produced in the chemical stage (IBES: Indirect Bioleaching with Effects Separation). This scheme permits the separate enhancement of each stage. On the one hand, the chemical attack of the ferric iron to sulphides can be performed at a higher temperature. On the other hand, the biological oxidation stage is more effective when biofilm models are applied. At the same time, inhibitory phenomena produced as a result of the bacterial breaking caused by the abrasion of the solid particles on microorganisms are prevented. In this work the 1BES process has been applied to a Spanish copper‐zinc and a copper sulphide concentrate. The objective has been to selectively dissolve zinc, which may be recovered by solvent exraction, the remaining residue being a copper concentrate suitable for pyrometallurgical treatment. The attributes of moderate temperature, atmospheric pressure, low cost of the leaching agent, flexibility and effectiveness make the process very attractive from an economic point of view.

The Evolution, Current Status, and Future Prospects of Using Biotechnologies in the Mineral Extraction and Metal Recovery Sectors

“…The term "deep in situ biomining" (DISB) has been used to describe an emerging approach for extracting and recovering base metals buried 1-2 km in the lithosphere [26][27][28]. DISB combines indirect bioleaching, where the abiotic dissolution of a sulfidic ore or concentrate by an acidic, ferric iron-rich lixiviant and the biological regeneration of oxidised iron following the stripping of the target solubilised metal(s), are spatially separated (e.g., Reference [29]) with in situ leaching (ISL) which is, as noted, not a new concept. An ISL process for recovering uranium was first introduced in the USA in 1959 and was estimated to account for 51% of global U production in 2014 [30].…”

Causes of inhibition of bioleaching by Cu are also thermodynamic

“…It is possible to accelerate bioleaching by carrying out the chemical leaching and biological Fe 2+ oxidation stages in separate locations, allowing optimisation of each independently. [15][16][17] Bio-oxidation can be improved using reactors designed specifically for this purpose. Among the tested designs, the one which has shown the greatest Fe 3+ productivities is the flooded packed bed reactor.…”

“…It is possible to accelerate bioleaching by carrying out the chemical leaching and biological Fe 2+ oxidation stages in separate locations, allowing optimisation of each independently . Bio‐oxidation can be improved using reactors designed specifically for this purpose.…”

Bio-dissolution of copper from Khetri lagoon material by adapted strain of Acidithiobacillus ferrooxidans

“…On other hand, conventional processes of concentrate produce many problems [6][7][8] in recovery of metals from wastes and low grade ores. This bio technique is economical and offers reduced environmental pollution.…”