Method for bioleaching a metal present in a material

Abstract

The invention relates to a method for recovering at least one metal present within a material, said material possibly including iron, said method including a step of supplying a ferrous ion, a step of supplying a ferric ion, and a step of bioleaching at least one metal present in the material by the ferric ions, each one of the steps being implemented by a particular bacterial population.

Description

FIELD OF THE INVENTION[0001]The invention relates to the field of biohydrometallurgy aimed at the recovery of ferrous and non-ferrous metals of interest present in a material by means of a bioleaching process. More particularly, the invention relates to an indirect bioleaching process for extracting at least one metal present in a material, and comprising the steps of supplying a ferrous ion in a first reaction space, of oxidizing the ferrous ion supplied to give a ferric ion in a second reaction space and of bioleaching said at least one metal via said ferric ion in a third reaction space.PRIOR ART[0002]Bioleaching processes consist in solubilizing metals present in the reduced or elemental state from various materials, such as ores, or solid by-products / waste resulting from the metallurgy industry, the mechanical industry, or the industry for converting or treating and recycling waste such as incinerator ash, batteries and spent catalysts, through the use of microorganisms. The me...

AI Technical Summary

Benefits of technology

The patent text describes a process for recovering metals of interest from materials using bacteria embedded in an immersed cell matrix. The bacteria are less exposed to toxic compounds and can allow the bioleaching process to go ahead even in the presence of these compounds. The process has the following technical effects: higher yield of metal recovery, faster process, and higher cell density leading to faster oxidation rates. The embedded bacteria can also carry out mixed cultures and the process can separate the microorganisms from the reaction medium and material, allowing easy recovery and reuse of the microorganisms and residual materials. The process of acclimatizing the microorganisms before use and separately acclimatizing each population can further enhance the effectiveness of the process.

Problems solved by technology

However, the processes thus described do not make it possible to obtain a high degree of recovery of the metals of interest, or the processes are relatively slow (from two to a hundred days), thus decreasing the profitability of these processes.

Thus, these processes are not satisfactory from the point of view of the yield and kinetics for recovering a not insignificant part of the metals of interest in order to make the process profitable from a technico-economic point of view.

Furthermore, some materials treated by bioleaching can comprise, depending on their nature, various compounds which can prove to be toxic and can reduce the microbial reliability and / or inhibit the growth and / or the activity of the microorganisms.

These compounds reduce the efficiency or prevent the biological treatment of the materials comprising them.

Currently, the hydrometallurgical, electrochemical (such as electrorefining) and pyrometallurgical processes do not make it possible to recover metals with a sufficiently high yield when the material comprises a low amount of metals of interest and / or if it comprises metals which cannot be separated by the simplest techniques, such as: arsenic, antimony, mercury, bismuth, magnesium and thallium.

These elements require pretreatments or the use of techniques which reduce the technical and economical profitability of the processes.