EA028575B1 - Consortium of mesophilic and moderately thermophilic chemolithotrophic bacteria for tank leaching of refractory sulphide-containing ores - Google Patents

Abstract

The invention relates to microbiology and biotechnology and can be used in biohydrometallurgy to extract gold and/or other metals from refractory sulphide ores. The object of the invention is to obtain a consortium of mesophilic and moderately thermophilic chemolithotrophic microorganisms oxidizing sulphide minerals. The problem is solved by isolating strains of mesophilic and moderately thermophilic microorganisms dominating in the ore deposits of Akmola and East Kazakhstan regions with high arsenic content and creation of a consortium of chemolithotrophic microorganisms deposited at KazNIIPPP LLP. Mesophilic microorganisms are represented by strains of Acidithiobacillus thiooxidans B-501, Acidithiobacillus ferrooxidans B-502 and Acidithiobacillus ferrooxidans B-508. A moderately thermophilic microorganism is represented by the strain Sulfobacillus thermosulfidooxidans B-511.

Description

The invention relates to microbiology and biotechnology. It can be used in biogeotechnology for the extraction of gold and / or other metals for the processing of refractory sulfide pyrite, arsenopyrite ore concentrates.

Refractory ores typically contain sulfide minerals such as pyrite and arsenopyrite, which can significantly reduce the degree of gold recovery by cyanidation. They also often contain carbonaceous substances with sorption activity with respect to the gold cyanide complex.

Fine particles of gold in sulfide ores are most often associated with arsenopyrite. Pyrometallurgical (firing) and hydrometallurgical (autoclave leaching, bacterial oxidation) methods are used to open finely dispersed gold from sulfide minerals in industry. The advantage of bacterial oxidation of sulfide minerals as a preliminary operation before sorption cyanidation is its economic efficiency (low capital and operating costs) with higher metal recovery, as well as environmental safety and the absence of environmental pollution by harmful emissions.

Known technology is known (Mshet, R.S. VetBn: §rgshdeg-Ug1ad, 1997) in which for the biooxidation of sulphide concentrates the consortium AshyyobasShik sa1yik, Berkrtpish kr., 8 and 1 £ obaschik kr. and the archaea of Rettoract, oxidizing sulfide gold-bearing minerals, sulfur and ferrous iron at a temperature of 45-50 ° C. The work (patent CA 2282848, C22B 3/18, 09/20/1999) describes a method for biooxidizing sulfide concentrates with a consortium of chemolithotrophic microorganisms Thiobacterium gioglo.xhapn, Thiobacterium gioglobacterium, Thiocheniculonides.

The closest topic is the work (patent of the Russian Federation No. 2332455 C2, application 2006128677/13, application. 07.08.2006, publ. 08.28.2008, bull. No. 24). The consortium proposed by the authors of the patent has a high oxidative activity with respect to sulfide minerals. The main disadvantages include the high dependence of the oxidative activity of the consortium on the pH of the pulp (the working range of the consortium's pH is below pH 1.4), as well as a narrow optimal temperature range (45-50 ° C).

The objective of the invention is to obtain a consortium of mesophilic and moderately thermophilic chemolithotrophic microorganisms that oxidize sulfide minerals.

The problem was solved by isolating strains of mesophilic and moderately thermophilic microorganisms that dominate in ore deposits of the Akmola region, with a high content of arsenic and the creation of a consortium based on them. The mesophilic microorganisms are represented by the strains of AShSHyuAsYyik (Yoo.xShapk AT100, deposited in KazNIIPPP LLP under the number V-501, ASHYObOasShik GettookhShapk AR102, deposited in KazNIIPPP LLP under the number B-502, ASHYObOpNo KazpNo KazpNoGo KazpNoShpNoKoSpOnGoNoGoNoGoNoGoKoGo. thermophilic microorganisms are represented by the strain §1GobasShik ShegshokShyoyohShapk KR-5, deposited in KazNIIPPP LLP under the number V-511, Certificate of deposit dated 15.11.2013 Depository of the Kazakh Scientific Research Institute of Food and Food Processing LLP howling industry 050060, Almaty, pr. Gagarina, 238 G.

The technical result consists in combining in a consortium of iron-oxidizing and sulfur-oxidizing bacteria, capable of growing at a wide temperature range (30-60 ° C), capable of acidifying the pulp with the subsequent activation of the entire oxidative potential of the consortium. In the process of their growth, these microorganisms further reduce the pH of the medium (1.0-2), thereby creating favorable conditions for the growth of acidophilic sulfur-oxidizing and iron-oxidizing bacteria. The use of acid-forming bacteria, more resistant to relatively high pH values (4.5-5.0), can significantly reduce the consumption of sulfuric acid during vat leaching.

The main characteristics of bacteria are determined.

Ashyyobasyyk ShuokhShapk AT100 was isolated from the mine water of the gold-bearing Zholymbet deposit in the Waxmann environment. Strain AT100 has the following characteristics.

Morphological signs.

This is a gram negative bacterium. Cells are small, rod-shaped, single and double. The cell size is 0.5x 1.0-4.0 microns. They do not form a dispute.

Cultural signs.

On a mineral nutrient medium with elemental sulfur forms a turbidity.

Physiological and biochemical properties.

Aerobe. Constructive exchange autotrophic. Organic matter inhibits growth. The energy for autotrophic carbon dioxide fixation is obtained through the oxidation of reduced sulfur compounds. Growth on an environment with elemental sulfur occurs without adaptation. The growth of bacteria and the oxidation of inorganic substrates occurs in the temperature range 15-35 ° C. The optimum growth temperature is 1 028575 et 29 ± 1 ° C. The optimal initial pH during growth on elemental sulfur is 4.0. The maximum decrease in pH on a medium with sulfur is up to 1.4.

Ac1bOiObasShik Geggoohlbai8 strain 02 was isolated from the mine water of the Quartzitic Gorki deposit on 9K medium. Strain ΆΡΊ02 has the following characteristics.

Morphological signs.

This is a gram-negative microorganism. Cells - small sticks, single and double. The cell size is 0.5x 1.0-4.0 microns. They do not form a dispute.

Cultural signs.

On a mineral liquid nutrient medium with ferrous iron (Fe8O ₄ x 7H ₂ O) forms turbidity, a small precipitate and the appearance of a brown color due to the oxidation of ferrous iron into oxide. On a mineral nutrient medium with elemental sulfur forms a turbidity.

Physiological and biochemical properties.

Aerobe. Constructive exchange autotrophic. Organic matter inhibits growth. The energy for the autotrophic fixation of carbon dioxide is obtained through the oxidation of ferrous iron, sulfides and reduced sulfur compounds. Growth on a medium with elemental sulfur occurs after preliminary adaptation. The growth of bacteria and the oxidation of energy substrates occurs at a temperature of 15-35 ° C. The optimum growth temperature is 29 ± 1 ° C. The optimal pH during growth on ferrous iron and sulfide minerals is 1.9 ± 0.1. The pH limits during the oxidation of Fe ²⁺ and sulfide minerals are 1.4-2.4. The optimal initial pH during growth on elemental sulfur is 4.0.

Ac1yylobaschi8 Gegohohlbaik strain LR108 was isolated from gold-bearing ore concentrate of the Zholymbet deposit. Strain ΛΡ108 has the following characteristics.

Morphological signs.

This is a small gram-negative stick. Cells are short, slightly thickened, single and double. The cell size is 0.6 x 1.0-3.0 microns. They do not form a dispute.

Cultural signs.

On a mineral liquid nutrient medium with ferrous iron (Fe8O ₄ x 7H ₂ O) forms turbidity, a small precipitate and the appearance of a brown color due to the oxidation of ferrous iron into oxide. On a mineral nutrient medium with elemental sulfur forms a turbidity.

Physiological and biochemical properties.

Aerobe. Constructive exchange autotrophic. Organic matter inhibits growth. The energy for the autotrophic fixation of carbon dioxide is obtained through the oxidation of ferrous iron, sulfides and reduced sulfur compounds. Growth on a medium with elemental sulfur occurs after preliminary adaptation. The growth of bacteria and the oxidation of energy substrates occurs at a temperature of 15-35 ° C. The optimum growth temperature is 29 ± 1 ° C. The optimal pH during growth on ferrous iron and sulfide minerals is 1.9 ± 0.1. The pH limits during the oxidation of Fe ²⁺ and sulfide minerals are 1.4-2.4. The optimal initial pH during growth on elemental sulfur is 4.0.

8GlObaschik 1bgtoki1yooohlbaik, strain KR-5, was isolated from ore from the Orlovka deposit (mine) on 9K8 medium.

8 and 1 Gobaschik 1 gtoki1boooh1baik, strain KM1, has the following characteristics.

Morphological signs.

Represent gram-positive sticks. Cells with rounded ends. The cell size is 0.6-0.8 x 1.0-6.0 microns. Cells are single, double and in short chains. Form spores. When growing on a medium with sulfur, it can form inclusions.

Cultural signs.

On a nutrient mineral medium with 4 g / l Pe ²⁺ forms a turbidity and the appearance of an orange color due to the oxidation of ferrous iron into oxide. On a mineral nutrient medium with elemental sulfur, it forms turbidity and sedimentation of sulfur.

Physiological and biochemical properties.

Aerobe. Mixotrophic constructive metabolism (in addition to autotrophic fixation of CO ₂ , insignificant additives of organic substances are required). They get energy due to the oxidation of ferrous iron, sulfide minerals and reduced sulfur compounds. Autotrophic growth is very weak. Growth on an environment with elemental sulfur occurs without adaptation. The growth of bacteria and the oxidation of energy substrates occurs at a temperature of 35-50 ° C. The optimum growth temperature is 50 ± 1 ° C. The optimal pH during growth on ferrous iron and sulfide minerals is 1.9 ± 0.1. The pH limits during the oxidation of Fe ²⁺ and sulfide minerals are 1.5-2.4. The optimal initial pH during growth on elemental sulfur is 3.0.

The invention is illustrated by the following specific examples.

Example No. 1.

The biooxidation of arsenopyrite flotation concentrate was carried out in 750 ml rocking flasks. A 100 ml pulp with a density of 10% (W: T ratio 9: 1), previously acidified to a pH of 1.8-2.0, was inoculated with a consortium. Biooxidation was carried out in a thermostatically controlled mode at

- 2 028575

35 ° C with vigorous stirring (180 rpm) for 4 days. Elemental and mineralogical analysis of ore are presented in table. 1 and 2, respectively. The dynamics of ore oxidation was evaluated by the content of sulfide sulfur. The ore oxidation curve is shown in FIG. one.

Table 1

The determined element, g / t Ai ^A yo Ai (consolidated) 1 Az Re 8 (sulfide) 24.7 7.3 2.3 12753.6 67485.1 68349.1

table 2

As a result, the complete oxidation of sulfide minerals was observed for 140 hours. After cyanidation of the bio-cake, 94.2% of the gold passed into the solution.

Example No. 2.

The biooxidation of arsenopyrite flotation concentrate was carried out in 750 ml rocking flasks. A 100 ml pulp with a density of 10% (W: T ratio 9: 1), previously acidified to a pH of 1.8-2.0, was inoculated with a consortium. Biooxidation was carried out in a thermostatic mode at 45 ° C with vigorous stirring (180 rpm) for 4 days. The elemental and mineralogical composition of the concentrate corresponded to example No. 1. The dynamics of ore oxidation was evaluated by the sulfide sulfur content. The ore oxidation curve is shown in FIG. 2.

Example No. 3.

The biooxidation of arsenopyrite flotation concentrate was carried out in 750 ml rocking flasks. A 100 ml pulp with a density of 10% (W: T ratio 9: 1), previously acidified to a pH of 1.8-2.0, was inoculated with a consortium. Biooxidation was carried out in a thermostatic mode at 50 ° C with vigorous stirring (180 rpm) for 4 days. The elemental and mineralogical composition of the concentrate corresponded to example No. 1. The dynamics of ore oxidation was evaluated by the content of sulfide sulfur. The ore oxidation curve is shown in FIG. 3.

More than 90% of sulfides were oxidized by 80 hours.

Example No. 4.

The biooxidation of arsenopyrite flotation concentrate was carried out in 750 ml rocking flasks. A 100 ml pulp with a density of 10% (W: T ratio 9: 1, pH 3.7) was inoculated with a consortium. Biooxidation was carried out in a thermostatic mode at 45 ° C with vigorous stirring (180 rpm) for 4 days. The elemental and mineralogical composition of the concentrate corresponded to Example No. 1. During the biooxidation, we monitored changes in the pH of the medium and the content of sulfide sulfur. The curves corresponding to the dynamics of pH and sulfide sulfur are shown in FIG. 4, 5.

The consortium is able to oxidize sulfide flotation concentrate without prior acidification of the pulp. At 30 hours, pulp pH decreased to 1.4. At 110 hours, more than 90% of sulfide sulfur was oxidized. The percentage of free gold was 94.3%.

Claims (1)

CLAIM Consortium chemolithotrophic microorganisms deposited at LLP KazNIIPPP to vat leaching refractory sulfide ores comprising mesophilic bacteria strains AsTsIYoasShik OioohDasch B-501, B-AsMIYoasShsh GeggoohDasch 502 AsShShyuasShik GeggoohDasch V508 strain and moderately thermophilic bacteria §i1GoasShi8 1egto8i1yyooh1yai8 B-511.