RU2385954C2 - Method of oxidation of sulphide minerals - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method of sulphide minerals oxidation includes feeding of pulp with sulphide minerals and oxidising agent into reactor with following its blending and outlet of oxidised composition from reactor. During blending of pulp and oxidising agent in internal chamber of reactor in turbulent conditions it is implemented mechanical activation of surface of solid phase of pulp and disperse of oxidising agent. Outlet of oxidised compositions from internal chamber into external chamber of reactor is implemented under action of pressure created by inlet flow of pulp through openings overlapped in top part of internal chamber by regulator of pulp outlet. Additionally liquid phase of pulp is continuously circulates from external chamber into internal chamber of reactor. Oxidation rate of sulphide minerals is regulated by means of changing of oxidising agent concentration in pulp ensured b changing of its amount form 3000 up to 15000 mg·l/h at activation of pulp in reactor.

EFFECT: invention provides reduction of sulphur content in treatment products of mineral raw material directed to following enrichment or metallurgical redistribution, increasing of reactor productivity.

1 dwg, 3 tbl, 3 ex

Description

The invention relates to the field of mineral processing, ecology, in particular the oxidation of sulfide minerals, and can also be used in metallurgy and chemical industry.

A known method of processing copper sulfide raw materials, including the oxidative treatment of raw materials simultaneously with two separation streams, the processing of raw materials with a particle size of less than 0.1 mm is carried out in a suspended layer in the prechamber with oxygen supply in an amount of up to 65% of theoretically necessary for the complete oxidation of the entire mass of sulfur, iron and impurities of the supplied material to oxides, and the remainder with a particle size of less than 0.1-50 mm is melted together with fluxes in the chamber [1].

The disadvantage of this method is the combination of the oxidation and smelting of the sulfide concentrate, which does not allow for a further enrichment cycle to produce rich concentrates of valuable components. In addition, the oxidation of sulfide raw materials during the combustion of oxygen in the prechamber leads to the formation of a significant amount of exhaust gas mixtures, which is a technologically and environmentally unsafe process.

The closest in technical essence is the method of oxidation of sulfide compounds, including the supply of pulp with sulfide minerals and an oxidizing agent to the reactor, followed by mixing and removal of the oxidized compounds from the reactor [2].

The disadvantages of this method are the destruction of the composition and physico-chemical properties of sulfide compounds during the oxidation process in several stages: oxidation → transfer of the liquid phase of the chemical compounds into the solid phase → dissolution of the solid phase in the liquid → withdrawal of the liquid oxidized phase from the reactor, accompanied by different rates, and also high cost of the method and low productivity. In addition, flammable and explosive substances such as acetone and ammonium nitrate are used in the oxidation of chemical compounds.

The objective of the invention is to reduce the sulfur content in the products of enrichment to a value at which it is possible to obtain high-quality products at metallurgical enterprises, and reduce sulfur emissions into the environment, as well as increase the productivity of the process of oxidation of sulfide minerals.

This is achieved by the fact that in a method comprising feeding pulp with sulfide minerals and an oxidizing agent to the reactor, followed by mixing and withdrawing the oxidized compounds from the reactor, while mixing the pulp and the oxidizing agent in the inner chamber of the reactor in a turbulent mode at Re> 2000, the surface of the solid is mechanically activated the pulp phase and dispersion of the oxidizing agent, and the oxidized compounds are removed from the inner chamber to the outer chamber of the reactor under the action of pressure created by the incoming pulp stream through the holes covered in the upper part of the inner chamber by a pulp output regulator made, for example, in the form of rods connected to a moving mechanism, while the oxidation state of sulfide minerals is controlled by changing the concentration of the oxidizing agent in the pulp by changing its amount from 3000 - 15000 mg / h upon activation of the pulp in the reactor and / or the duration of the oxidation of sulfide minerals in the inner chamber by changing the amount of pulp continuously circulating between the outer and inner chambers p actor.

The use of the inner and outer chambers of the reactor allows simultaneous oxidation of sulfide minerals by mechanochemical activation in the inner chamber and the separation of the pulp into solid (oxidized phase) and liquid phase (recycled water) in the outer chamber.

The mechanical activation of the surface of the oxidized solid phase due to the creation of a turbulent pulp regime with a velocity gradient of 5000-40000 s ^-1 in the inner chamber of the reactor allows increasing the oxidation state of sulfide minerals by self-abrasion of their surface, as well as achieving a high dissolution rate of ozone in water with agitators, which are both dispersants.

The input and output of the pulp from the inner chamber of the reactor is controlled by the pressure created by the incoming pulp stream through the adjustable openings of the inner chamber, which makes it possible to control the duration of the oxidation of sulfide minerals in the inner chamber.

The use of the liquid phase of the pulp, continuously circulating from the outer chamber to the inner chamber of the reactor, allows to reduce oxidizer losses and to achieve the maximum possible turnover of the reactor process water.

The drawing shows a schematic diagram of a reactor for implementing the method of oxidation of sulfide minerals.

The reactor consists of external and internal chambers 1, 2, pipes 3 and 4 for feeding the pulp with sulfide minerals and feeding the oxidizing agent into the inner chamber 2 of the reactor, two dispersing mixers 5, 6 installed on the pipe 4 in the inner chamber 2, the feed control system and output pulp from the inner chamber 2, including the feed control of the original pulp, made, for example, in the form of a damper 7 installed at the inlet of the pipe 3, and the pulp output regulator, made in the form of rods 8, overlapping holes 9 in the upper part of the inner chamber 2 pos COROLLARY, e.g., a moving mechanism 10 and the pump 11 for circulation of the clarified liquid pulp phase from the outer chamber into the inner chamber 1 of the reactor 2 through slurry pipeline 12. Each impeller-disperser consists of several perforated plates mutually offset through the same angle. The inner chamber 2 is equipped with a hinged emergency hatch 13 for unloading the solid phase of the pulp. A crane 14 is installed at the base of the external chamber 1 to collect and withdraw the oxidized solid phase from the reactor. The amount of sulfur in the oxidized product is determined by a spectrophotometric analyzer in the laboratory.

The method is as follows.

Initial pulp in the ratio T: L = 1.5: 2 is simultaneously fed into the inner chamber of reactor 2 through a pipe 3 and an oxidizing agent, such as ozone, through a pipe 4. In this chamber, the pulp is mixed with an oxidizing agent by means of dispersing mixers 5, 6, creating turbulent movement of the pulp. As a result, the surface of the oxidized solid phase of the pulp is mechanically activated, which increases the degree of oxidation of sulfide minerals and also provides a high dissolution rate of the reaction products in the pulp with the formation of hydrated complexes of sulfuric acid and elemental sulfur. This leads to a change in the pH of the liquid phase in the inner chamber, and therefore, intensifies the process of oxidation of the solid phase. The optimal mode of oxidation of sulfide minerals is also provided by changing the concentration of ozone in the inner chamber 2 in an amount of from 3000 to 15000 mg · l / h for a given amount of the initial pulp in this chamber. If the sulfur content in the solid phase of the pulp exceeds 0.5%, it is necessary to increase the duration of the activation process of sulfide minerals by regulating the supply and withdrawal of pulp from the inner chamber 2 and / or to intensify this process by changing the speed of rotation of the dispersing agitators 5, 6. To reduce oxidizer losses during reactor operation and to maintain the achieved pH in the inner chamber 2, the clarified liquid phase of the pulp in the outer chamber 1 is continuously circulated from it to the inner chamber 2 of the reactor through tion pump 11 through the slurry pipeline 12. Thus there is a circulation reactor process water in a closed loop. During commissioning, unloading of the solid phase of the pulp from the inner chamber 2 is carried out through the hatch 13. Oxidation products under the influence of gravitational forces are deposited on the basis of the outer chamber 1, which are removed from the reactor through the valve 14. In the process of oxidation of the solid phase of the pulp, the content is continuously monitored sulfur in the oxidized product to ensure optimal reactor operation.

Thus, this method allows to improve the quality of mineral processing products sent for further enrichment or metallurgical processing, reducing their sulfur content to 0.06%.

Example 1

The method of oxidation of sulfide minerals is carried out under standard thermodynamic conditions. The oxidation modes of sulfide minerals using an oxidizing agent - ozone in the inner chamber 2 of the reactor are presented in tables 1, 2.

As a result of the mechanochemical activation of sulfide minerals, the oxidation of sulfides occurs, with the formation of elemental sulfur and iron oxides:

for pyrite

The indicators of the oxidation process of magnetite concentrate containing pyrite at the inlet and outlet of the reactor are presented in table 1.

Table 1 Indicators at the entrance at the exit The degree of conversion,% S,% 0.25 0,061 75.3 The amount of ozone produced by the ozonizer, mg · l / h 3000 - PH value 7.0 5.9 - The frequency of rotation of the agitators, dispersants, rpm 5000 - Temperature ° C 20.3 22.1 - Activation time, min 7 -

Example 2

The method of oxidation of a magnetite concentrate containing monoclinic pyrrhotite was carried out under similar conditions and conditions shown in table 2.

As a result of the mechanochemical activation of monoclinic pyrrhotite, a mixture of new phases is formed:

The indicators of the oxidation process of magnetite concentrate containing monoclinic pyrrhotite at the inlet and outlet of the reactor are presented in table 2.

table 2 Indicators at the entrance at the exit The degree of conversion,% S,% 0.183 0.06 67.2 The amount of ozone produced by the ozonizer, mg · l / h 7000 - PH value 7.0 6.2 - The frequency of rotation of the agitators, dispersants, rpm 10,000 - Temperature ° C 21.3 22.1 - Activation time, min 10 -

Example 3

The method of oxidation of sulfide minerals is carried out under standard thermodynamic conditions. The oxidation modes of sulfide minerals using an oxidizing agent - compressed oxygen supplied to the inner chamber 2 of the reactor are presented in table 3.

As a result of mechanochemical activation of a concentrate concentrate obtained from gold-bearing ores, in which sulfur is represented by sulfides, in particular argentite, containing 11.9% sulfur, they are oxidized, with the formation of water-soluble sulfates:

for argentite:

In this case, sulfur leaves the concentrates before they are smelted into the pulp together with sulfates, and silver recovery is achieved by chlorination with precipitation of silver chlorides, electrolysis, etc.

The indicators of the oxidation process of a concentrate concentrate containing argentite at the inlet and outlet of the reactor are presented in table.3.

Table 3 Indicators at the entrance at the exit The degree of conversion,% S,% 3.45 0.1 0.97 The amount of oxygen supplied from the oxygen cylinder through the gearbox, mg · l / h 3000 - PH value 7.0 6.9 - The frequency of rotation of the agitators, dispersants, rpm 5000 - Temperature ° C 20.3 22.1 - Activation time, min 7 -

Based on the results obtained on the oxidation of sulfide minerals, it should be noted that this method of oxidation of sulfide minerals allowed to reduce the sulfur content in mineral processing products to 0.06% and to increase the performance of the oxidation reactor by reducing and intensifying the oxidation process of sulfide minerals.

Information sources

1. RF patent No. 2298587, class. СВВ 15/00 dated 12/27/2005.

2. RF patent No. 2309009, according to cl. B01J 19/18, B01J 3/04, C02F 1/72 dated 08/30/2005 (prototype).

Claims (1)

A method of oxidizing sulfide minerals, including feeding pulp with sulfide minerals and an oxidizing agent to the reactor, followed by mixing and withdrawing the oxidized compounds from the reactor, characterized in that when mixing the pulp and the oxidizing agent in the inner chamber of the reactor in a turbulent mode, the surface of the pulp solid phase is mechanically activated and oxidizer dispersion, and the oxidized compounds are removed from the inner chamber to the outer chamber of the reactor under the influence of pressure generated by the incoming sweat lump of pulp through openings blocked in the upper part of the inner chamber by a pulp discharge regulator, while the oxidation state of sulfide minerals is controlled by changing the concentration of oxidizing agent in the pulp by changing its amount from 3000 to 15000 mg l / h upon pulp activation in the reactor, and the pulp phase is continuously circulated from the outer chamber to the inner chamber of the reactor.

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