Method of controlling process of biooxidation of sulphide concentrates

FIELD: chemistry.

SUBSTANCE: method includes controlling flow of air fed for biooxidation and the rate of mixing in a tub where biooxidation is carried out, based on concentration of divalent iron ions in a pulp, while ensuring a near zero concentration value. When the concentration of divalent iron ions in the pulp increases to more than 0.5-1.0 g/dm3, the flow of air fed for biooxidation and the rate of mixing are increased. In the absence of divalent iron ions in the pulp, the flow of air fed for biooxidation and the rate of mixing are reduced until traces of divalent iron ions appear to a near zero concentration.

EFFECT: simple, accurate and fast control of the process of biooxidation of sulphide concentrates, high redox potential and efficiency of biooxidation of sulphide concentrates, low power consumption of biooxidation.

2 ex

 

The invention relates to hydrometallurgy of non-ferrous and noble metals, namely the extraction of metals from sulphide ores and dressing products, in particular products and wastes from mining and metallurgical industries, mineral waste, including concentrates, middlings and tailings, slag, sludge, cinders, etc. the Invention can be used for the extraction of copper, zinc, Nickel, etc. in the leaching solution, followed by extraction of metals from solution, for opening the gold, silver and other precious metals, finely disseminated in sulphide for the purpose of increasing their removal in subsequent processes.

Biooxidation of sulfide ores and concentrates is the least costly and not environmentally stressful way of leaching and the opening of the metals, as is carried out at atmospheric pressure, a primary oxidant, ferric ions Fe(III) in sulfuric acid formed in the reaction zone the oxidation of ions of Fe(II) aerobic autotrophic or mixotrophy zhelezookisnye bacteria.

One of the main parameters that determine the speed and efficiency of bacterial oxidation of ferrous iron and sulphide oxidation ferric ions, is the flow of air or other oxygen-containing gas, in particular who�ear, enriched with oxygen and/or carbon dioxide. For the dissolution of oxygen and carbon dioxide on the oxidation air is dispersed through the aerators under stirring device, so the dissolution of oxygen and air consumption biooxidation depend on the intensity of mixing design and speed of rotation of the mixing devices.

The air flow in the biooxidation of sulphide concentrates and the intensity of mixing is determined at the design stage and is not regulated by changes in the composition of sulfide concentrates, the content of the solid phase, performance (load), etc.

In the most familiar ways of biooxidation of gold-bearing sulphide concentrates with the participation Glazovskaya mesophilic bacteria "BIOX@process" (US No. 4822413, publ. 04.06.1987) and thermotolerant bacteria "BacTech@process (AU No. 652231, publ. 21.10.1992) total airflow is constant and does not adjust when you change the mineral composition of the concentrate, the content of solid phase in the leaching speed of the process and environment parameters.

In the methods of processing of sulphide copper-zinc products (RU # 2203336, publ. 05.03.2002 and RU №2005113258, publ. 20.10.2006) using bacteria, the intensity of aeration and mixing of specified volumetric mass transfer coefficient for oxygen in the range of 200-800 h-1without specifying how e�about handling.

In the method of processing of primary gold sulfide ores BIONORD (RU # 2256712 SS 11/00, 3/18, publ. 20.07.2005) aeration of the pulp in the bio-oxidation is carried out with compressed air with constant specific flow rate of 0.5 m3/m3.

In the method for processing refractory gold-arsenic ores and concentrates BIOS (EN 2234544, publ. 20.08.2004) the use of aerators, providing at constant air flow rate oxygen concentration in the slurry is not less than 2-3 mg/l, and does not take into account the activity of the biomass on the oxidation of iron.

The closest analogue is a method of controlling the process of biooxidation of sulphide concentrates (EA 200800805, publ. 30.10.2008), including regulation of the flow rate of the air supplied to the oxidation, and energy on electric mixers, i.e. the intensity of mixing in the tank, where biooxidation conducted on the basis of the measurement or calculation of oxygen consumption depending on the mineral composition of sulphide concentrate.

Determination of oxygen consumption by this method is not really characterizes the necessary amount of oxygen for bio-oxidation of iron and sulfide concentrates. Oxygen consumption calculated on the basis of the calculation depending on the composition of the sulfide material and the expected rate of oxidation, can be used in the design of the aeration system d�I estimate the marginal and average values of air flow rate, as only partially reflects the real conditions of biooxidation, for example does not take into account important indicator of biooxidation as the activity of the biomass in the oxidation of iron.

Oxygen consumption based on the measurements supplied to the reactor of oxygen, the dissolved oxygen concentration in the environment and the oxygen concentration in the exiting gas is not precisely determines the necessary amount of oxygen for the oxidation. For example, a high concentration of dissolved oxygen indicates that oxygen consumption is small and it can be reduced, but at the same time is a sign of good conditions of mass transfer in gas-liquid, and may be the reason for the low activity of the biomass and the rate of biooxidation, compounded by reducing the flow of oxygen.

Used energy consumption per unit mass of sulphide material does not reflect the effectiveness of biooxidation. The implementation of this method is complicated, as it requires a large amount of instrumentation and controls, application for determination of control parameters sealing bioreactors.

The technical result achieved by the present invention is more simple, precise and operational management of the process of biooxidation of sulphide concentrates with the participation Glazovskaya microorganisms. Additional re�ulticom the implementation of the method can be increased redox potential and effectiveness of biooxidation of sulphide concentrates, and reducing energy consumption for biooxidation.

Said technical result management process of biooxidation of sulphide concentrates with the participation Glazovskaya of microorganisms is achieved by regulating the flow rate of the air supplied into the slurry in the oxidation, and the rate of mixing of the pulp in the VAT, depending on the concentration of ions of bivalent iron in the slurry, thus increasing the concentration of divalent iron in the pulp than 0.5-1.0 g/DM3airflow and agitation of the pulp increases, and in the absence of ions of bivalent iron in the pulp flow and the mixing speed is reduced to the appearance of traces of ions of bivalent iron.

Oxygen is used by aerobic bacteria as acceptor in the chain of electron transfer in the oxidation of iron, and for the oxidation of ions of bivalent iron to trivalent, which is the oxidant of sulfide.

The oxidation reaction of iron from divalent to trivalent, with the participation of oxygen (1) catalyzed zhelezookisnye bacteria has a greater velocity compared to the speed of other reactions that occur during the bio-oxidation of sulfide minerals, for example reactions of oxidation of arsenopyrite and pyrite (2), (3), so the presence of ferrous iron in the liquid phase of biocycle�I indicates the deficit of dissolved oxygen.

With a lack of dissolved oxygen in the process of biooxidation slowed and stopped, resulting in the solution appears ferrous iron, whose concentration increases with the increase in the deficit of oxygen, redox potential decreases, the rate of sulphide oxidation is reduced.

The lack of oxygen in the bio-oxidation may be a consequence of low income, and low mass-transfer characteristics of gas-liquid, and can be removed by increasing the flow of oxygen-containing gas or the rate of mass transfer gas-liquid, for example by increasing the degree of dispersion of oxygen-containing gas by increasing the mixing speed.

When you change the mineral composition of sulphide concentrates, the content of solid phase in the slurry bio-oxidation, performance, etc. the presence or absence of divalent iron in the pulp signals the need to regulate the flow of oxygen, or dissolved due to the mixing intensity.

By increasing the concentration of divalent iron in the pulp than 0.5-1.0 g/DM3for effective bio-oxidation air consumption biooxidation should be increased to the disappearance of bivalent iron.

If too much air flow� on biooxidation occurs coalescence of air bubbles, accelerate their recovery and exit from the apparatus and the reduction of dissolved oxygen and carbon dioxide, worsening conditions of work of agitators, stirrers "choke" in the formation of the cork gas mode, as a result, the bio-oxidation are reduced.

In the absence of divalent iron in the pulp of biooxidation of the air flow in the biooxidation and the mixing speed can be reduced, and as a result reduce energy costs by biooxidation.

Regulation of air flow rate and stirring speed on the concentration of divalent iron in the slurry is simple and sufficiently accurate method of controlling the process of biooxidation of sulphide concentrates and allows you to control promptly.

Managing the process of biooxidation of sulphide concentrates regulation of air flow rate and stirring speed, which provides the necessary amount of oxygen for bio-oxidation of iron and life of bacteria, but not significantly exceeding this amount can improve process efficiency and reduce operating costs for aeration.

The invention is illustrated by examples of the method.

Example 1.

Management of bio-oxidation of sulphide gold concentrate flotation beneficiation particle size is 100% of the class minus 0.074 mm, containing pyrrhotite 27%, �arsenopyrite 20%, the antimonite 7% pyrite 15% involving the Association Glazovskaya bacteria by regulating the flow of air in six vats with mechanical stirring and bubbling of air, depending on the concentration of ions of bivalent iron in the slurry reduces the flow of air as compared to the design performance in the first vats 1.2 times, in the 5th Chan 2.0 times, 6 Chan 2.4 times. The total air flow for biooxidation of the concentrate decreased 1.6-fold, respectively and decreased the cost of electricity for aeration.

The extent of biooxidation of gold-bearing sulphide concentrate was as follows: pyrrhotite and arsenopyrite 98-99%, antimonite 74%, pyrite 63%, the recovery of gold from Keck bio-oxidation cyanidation increased by 2.1% compared to the control experiment without a control process of biooxidation depending on the concentration of ions of bivalent iron in the pulp.

Example 2.

For bio-oxidation was used stale zinc-containing tailings of flotation beneficiation of size 65% class - 0,044 mm, containing 5.6% of zinc, 12,96% sulfur and 11.6% of iron, the main ore minerals are pyrite 25-30%, sphalerite 7-8%, pyrrhotite 7-10% and markesic, arsenopyrite, chalcopyrite, Galena - only 5-7%. Bio-oxidation of the zinc flotation tailings was carried out in continuous mode the cascade of three successive vats with mechanical paramashiva�education and aeration air, with the participation of the Association of mesophilic Glazovskaya bacteria in an aqueous solution of sulfuric acid at a pH of 1.5-2.1, the concentration of ferric iron 10,5-15,0 g/l, the solids content of 40%.

Managing the process of biooxidation of mill tailings by changing the speed of agitation of the pulp in vats depending on the concentration of iron ions in the pulp, with the appearance of ferrous iron in the pulp to a concentration of 1.0 g/l of the rotation speed of the stirrer was gradually increased from 350 to 400 rpm, and in the absence of ions of bivalent iron in the slurry, the speed of rotation of the agitator gradually decreased until the appearance of traces of iron ions. In the result management process for 98 hours of biooxidation of the extraction of zinc in the solution is increased compared to the control experiment was 2.7%.

A method of controlling the process of biooxidation of sulphide concentrates with the participation Glazovskaya of microorganisms, including regulation of the flow rate of the air supplied into the slurry in the oxidation, and the rate of mixing of the pulp in the VAT, characterized in that the flow rate of the air supplied to the pulp in biooxidation, and agitation of the pulp is adjusted depending on the concentration of ions of bivalent iron in the slurry, thus increasing the concentration of divalent iron in the pulp than 0.5-1.0 g/DM3the flow rate of the air supplied to the oxidation, and agitation of the pulp increases, and in the absence of ions of bivalent iron in the slurry, the flow rate of the air supplied to the oxidation, and the mixing speed is reduced to the appearance of traces of ions of bivalent iron.



 

Same patents:

FIELD: mining.

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FIELD: metallurgy.

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14 cl, 1 tbl, 1 ex

FIELD: chemistry.

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EFFECT: selective extraction of iridium from chloride solutions of platinum-group metals.

2 cl, 4 tbl, 4 ex

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