This review describes the historical development and current state of metals leaching and sulfide mineral biooxidation by the minerals industries. During the past 20 years commercial processes employing microorganisms for mineral recovery have progressed from rather uncontrolled copper dump leaching to mineral oxidation and leaching in designed bioheaps for oxidation of refractory gold ores and...

Smoluchowski 's coagulation equation with coagulation rates K 0 oc (ij) ~ describing the temporal evaluation of the size distribution ck (concentration of k-mers) is studied in the presence of a source term ark, and a sink term --bCk. With a' a/b 2 one finds that a steady state is reached, exhibiting gelation when w > 1⁄2 and a ' > ao(w), where a0(o~) depends on w (ao(w) = ~ for ~o < 1⁄2, ao(1)...

Impeller stirred tanks (STR) are commonly used in the chemical processing industries (CPI) for a variety of mixing and blending technologies. In the present research, a numerical study of flow and mixing inside turbulently agitated tanks were carried out. An efficient solution algorithm was developed to solve turbulent flow inside stirred tanks where the boundary conditions for moving impeller ...

The objective of this work is to make use of methodologies and tools from nonlinear Lyapunov theory in the design of bounded control laws for the temperature stabilisation of Continuous Stirred Tank Reactors CSTRs with exothermic or endothermic reactions Simple output feed back control laws i e control laws that feed back only the available mea surements are designed It is shown that these cont...

This paper presents simulation experiments on the continuous stirred tank reactor (CSTR) which is widely used equipment mainly in the chemical industry. The behaviour of these types of systems is usually nonlinear with other negative properties such as a time-delay or a non-minimum phase behaviour and simulation could help us with the understanding of them without making real experiments which ...

A simple biodegradation system consisting of an air stripping tank and a bioreactor was proposed for the treatment of volatile organic chemicals in wastewater. Toluene was used as a model of volatile organic chemicals. An aqueous solution of toluene and a basic mineral medium were placed in the air stripping tank and bioreactor, respectively. Toluene was stripped by supplying compressed air int...

Bacterial pre-oxidation of refractory gold concentrates generates large volumes leachate and requires a significant supply nutrients to support bacterial growth. Therefore, bioleachate reuse reduces both water consumption the required for process. However, efficiency this method its benefit need be further explored. In present study, two tests on in new cycles oxidation were carried out evaluat...