RU2520292C1 - Processing of sulphide copper-lead-zinc materials - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: proposed method comprises locating of concentrate into converter and its oxidative smelting. First, matte is poured into converter to blow it with coal-air mix at coal consumption of 500 kg per ton of matte at coal-to-air ratio of 0.35 kg/m³. Concentrate is loaded on fused matte surface to blow it with air enriched with oxygen to 25 vol. % to complete smelting of concentrate. Quartz and lime flux are loaded to proceed with blowing to produce the slag and matter rich in copper, both are, now, discharged by 70% to resume melt blowing with coal-air mix.

EFFECT: simplified process.

2 tbl, 7 ex

Description

The invention relates to the field of non-ferrous metallurgy, in particular to the metallurgy of copper, and can be used in copper smelters that process sulfide polymetallic concentrates.

Copper-lead-zinc sulfide concentrates are the product of the enrichment of the same ore. The complex composition of the ores, the thin intergrowth of the minerals of copper, lead and zinc often do not allow to obtain high-quality copper, lead and zinc concentrates suitable for processing by standard technologies. In this case, it is more expedient to produce collective concentrate in the presence of an effective technology for its metallurgical processing.

A known method of processing copper zinc-containing materials (US Pat. RU No. 2364640 C1, IPC C22B 15/06, publ. 08/20/2009), including pouring matte into a converter, converting it by blowing air in two stages with the addition of air to the second stage with fuel, loading copper zinc-containing materials into the converter and obtaining rich matte or blister copper and zinc sublimates in the exhaust gases. In this case, the loading of copper zinc-containing materials is carried out at the second stage of conversion after the discharge of slag and the appearance of the first portions of metallic copper.

The disadvantage of this invention is the inevitability of heterogenization (thickening) of the melt in the converter due to the oxidation of iron concentrate to magnetite, since the melting is carried out without the addition of fluxes. In addition, lead will not be sublimated in the form of sulfide or oxide, but will be reduced by metallic copper to metal and will eventually turn into blister copper, which will extremely negatively affect its quality and cause serious difficulties in subsequent refining.

,A known method of processing sulfide materials (US Pat. SU No. 1591499 C, IPC C22B 13/02, publ. 08/10/1999), containing lead, copper and zinc, including firing and smelting in suspension in a mixture with fluxes, working products crushed by a carbon reducing agent at a stoichiometric oxygen consumption for the oxidation of lead, zinc, and iron at an oxygen consumption of 1 kg of sulfur in the mixture $$0.7\left(\mathrm{one}-P\frac{C_{Cu}}{C_S}\right)$$

,

where P = 0.65-1.3; C _Cu and C _S — copper and sulfur content in the mixture (wt.%), Selective reduction of lead oxides from the dispersed melt in the carbon-containing reducing agent layer, carbon thermal reduction of zinc, copper recovery, characterized in that in order to increase the recovery of copper and lead in the rough metal due to a more complete separation of lead and copper between the products of smelting, the main flux is introduced into the firing-melting in the amount of 0.41-0.56 kg CaO per 1 kg of iron and 1.4-2.0 kg CaO per 1 kg of silicon dioxide in mixtures form a homogeneous oxysulfide melt, from torogo reduced lead and zinc, and copper is then removed.

The disadvantage of this invention is the inevitable “smearing” of lead by smelting products (lead, matte, slag, dust), since the authors ’goal - to extract lead in the form of metal as much as possible - can be achieved with the maximum oxidation of lead sulfide to oxide. This is possible only with a high oxygen flow rate with blast, and hence a high temperature in the charge-oxygen melting torch. Under these conditions, the high vapor pressure of sulfide and lead oxide will lead to a significant transition into the gas phase.

The closest in technical essence is the method of processing copper-lead-zinc concentrate by pyroselecting in a converter (Babadzhan A. A. Pyrometallurgical selection. M .: Metallurgy, 1968, 298 pp.), Which includes loading lump coke into an empty converter, feeding it to air blast through tuyeres, loading on coke and smelting of copper-lead-zinc concentrate with distillation of lead into the gas phase in the form of volatile sulfide and oxide. If you encounter difficulties with the melting of the concentrate, the matte is poured into the converter.

The disadvantage of this method is the difficulty of its implementation in terms of loading into the converter and kindling coke on the tuyeres, as well as melting the concentrate on it. During the coke ignition period, the off-gas converter gases contain a lot of carbon monoxide, and elemental sulfur, carbon disulfide and sulfur dioxide are added to it during the period of concentrate melting and oxidation. A sharp change in the composition of the gas, the need for afterburning elemental sulfur, carbon monoxide and carbon disulfide compounds significantly complicate its utilization in sulfuric acid production. In addition, melting is carried out without the addition of fluxes, which, ultimately, leads to the oxidation of slag, saturation with magnetite and heterogenization (thickening). The author of the method proposes to deal with this careful pouring of the matte into the converter, however, this operation is unsafe and can lead to an emergency ejection of the melt from it.

The technical result of the present invention is the elimination of difficulties in smelting associated with the disposal of complex in the composition of the Converter gases, as well as with the heterogeneous melt in the Converter.

The technical result is achieved in a method for processing sulfide copper-lead-zinc concentrate, which includes loading the concentrate into the converter and its oxidative smelting. Initially, the matte is poured into the converter and blown with a carbon-air mixture with a coal consumption of 500 kg / t matte with a volumetric ratio of coal to air 0.35 kg / m ³ , the concentrate is loaded onto the surface of the molten matte, after which the matte is blown with oxygen enriched air up to 25 vol .%, until the concentrate is completely melted, quartz and lime fluxes are loaded and purging is continued to ensure slag and copper-rich matte are obtained, the resulting slag and copper-rich matte are drained by 70% and the processing process is resumed by purging melt with a carbohydrate mixture.

The essence of the proposed method is as follows: initially, the matte is poured into the converter in an amount sufficient to immerse blowing tuyeres into it. Then, a carbon-air mixture is fed into the matte melt through them. After heating the melt to 1200-1250 ° C, copper-lead-zinc concentrate in the amount of 500-600% by weight of the matte is loaded onto its surface. The matte is purged with oxygen-containing blast until the concentrate is completely melted, after which quartz and lime fluxes are loaded. The melt is blown continuously to obtain slag and matte rich in copper.

At all stages of the concentrate processing, there are no conditions for a drastic change in the composition of the exhaust gases. They always contain sulfur dioxide and minimal amounts of carbon monoxide, elemental sulfur and carbon disulfide compounds. This is ensured by the constant presence in the converter of sulfides in the form of matte and concentrate, as well as a certain ratio of oxygen, carbon and sulfur supplied to the converter.

Examples of the method

Processing of copper-lead-zinc concentrate was carried out in a combined smelting-converting unit (SFC), which is a 140-ton horizontal converter with a diameter of 3.95 m and a length of 16.6 m, with a neck (2 × 3 m) shifted to the end for removal gas, equipped with a system for supplying the mixture to the surface of the melt through a special loading hole with a diameter of 400 mm

The blast required to conduct the melting process in an amount of 27-32 thousand nm ³ / h is supplied through a tuyere belt of 24 tuyeres with a nominal diameter of 47 mm.

Concentrate and fluxes are fed from feed hoppers to the SPK unit through the feed opening. Fine coal or carbon-containing material is blown through the tuyeres with a pneumatic chamber pump.

Rich matte and slag are poured through the neck into ladles and sent for further processing: matte is converted to blister copper, and the slag is planned to be sent to further decontaminate and recover zinc and lead residues by electric melting, followed by fuming.

The exhaust gases from the throat of the SPK unit through the vaporizer with vapor-cooled and a dust chamber enter the thermosiphon cooler and then to the bag filter for fine cleaning. After cleaning, the gases are sent to the sulfuric acid workshop.

Table 1 The chemical compositions of the starting materials, wt.% Material Si Pb Zn Fe S SiO ₂ CaO FROM Cu-Pb-Zn Concentrate 9.1-13.1 18.9-24.4 10.9-21.4 5.5-19.5 19.0-30.7 1,5-10,1 0.5-2.0 - Matte source 26.0-30.0 1.1-3.0 2.5-3.5 36.0-40.0 23.5-25.0 - - - Quartz - - - 4.0-5.7 1.0-1.5 68.0-71.0 2.7-3.3 - Lime - - - 0.4 0.27 0.82 69.01 - Coal - - - 0.5-0.8 0.2 0.6-1.5 0.3-0.4 91-92

table 2 The chemical compositions of matte and slag, wt.% Material Si Pb Zn Fe S SiO ₂ CaO Matte rich 50-77.8 1.3-10.6 0.5-1.5 0.9-9.3 10,4-17,1 0.11-12.8 0.01-3.0 Slag 1.15-5.73 2.1-4.7 5,6-12,7 34.3-44.9 1.3-4.0 18.6-22.1 2.3-6.0

Example 1

30 tons of matte were poured into the SEC unit and the melt was blown with a carbon-air mixture with a coal content of 0.35 kg / m ³ and with a coal consumption of 500 kg / t of matte. In the process of blowing the melt with air enriched with oxygen up to 25% vol., 100 tons of concentrate were loaded, and after its melting 16 tons of quartz and 4 tons of lime. The purge was carried out to obtain slag and rich matte.

After the slag and matte were drained, 30-35 tons of melt were set aside in the SEC unit, and the entire cycle, starting with the supply of the air-carbon mixture, was repeated again.

The average content of sulfur dioxide in the exhaust gases, the samples of which were taken under a dust cover periodically throughout the entire processing process, amounted to 7-9% vol. During the processing, melt heterogenization was not observed, after the discharge of the melts in the aggregate, no accumulation of refractory unmelted residues was noted.

Example 2

30 tons of matte were poured into the SEC aggregate and the melt was blown with a carbon-air mixture with a coal content of 0.3 kg / m ³ and with a coal consumption of 500 kg / ton of matte. In the process of blowing the melt with air enriched with oxygen up to 25% vol., 100 tons of concentrate were loaded, and after its melting 16 tons of quartz and 4 tons of lime. The purge was carried out to obtain slag and rich matte.

During the purging process, the melt temperature did not exceed 1150 ° С, slag formation proceeded with poor flux uptake, after the slag and matte were drained, insoluble quartz flux remained in the converter, the slag melt turned out to be oxidized, with a magnetite content of more than 30%.

Example 3

30 tons of matte were poured into the SEC unit and the melt was blown with a carbon-air mixture with a coal content of 0.4 kg / m ³ and with a coal flow rate of 500 kg / t of matte. In the process of blowing the melt with air enriched with oxygen up to 25% vol., 100 tons of concentrate were loaded, and after its melting 16 tons of quartz and 4 tons of lime. The purge was carried out to obtain slag and rich matte.

During the purging process, the melt temperature increased to 1300 ° С, there were no problems with slag formation and melt heterogenization, however, increased wear of the protective skull on the refractory masonry in the vicinity of the tuyere belt was noted.

Example 4

30 tons of matte were poured into the SEC unit and the melt was blown with a carbon-air mixture with a coal content of 0.35 kg / m ³ and with a coal consumption of 450 kg / t of matte. In the process of blowing, the melt with air enriched with oxygen up to 25% vol., Loaded 100 tons of concentrate, and after its melting 16 tons of quartz and 4 tons of lime. The purge was carried out to obtain slag and rich matte.

During the purging process, the melt temperature did not exceed 1150 ° С, slag formation proceeded with poor flux uptake, after the slag and matte were drained, insoluble quartz flux remained in the converter, the slag melt turned out to be oxidized, with a magnetite content of more than 30%.

Example 5

30 tons of matte were poured into the SEC unit and the melt was blown with a carbon-air mixture with a coal content of 0.35 kg / m ³ and with a coal consumption of 550 kg / t of matte. In the process of blowing the melt with air enriched with oxygen up to 25% vol., 100 tons of concentrate were loaded, and after its melting 16 tons of quartz and 4 tons of lime. The purge was carried out to obtain slag and rich matte.

During the purging process, the melt temperature increased to 1300 ° С, there were no problems with slag formation and melt heterogenization, however, increased wear of the protective skull on the refractory masonry in the vicinity of the tuyere belt was noted.

Example 6

30 tons of matte were poured into the SEC unit and the melt was blown with a carbon-air mixture with a coal content of 0.35 kg / m ³ and with a coal consumption of 500 kg / t of matte. In the process of blowing the melt with air enriched with oxygen up to 25% vol., 100 tons of concentrate were loaded, and after its melting 16 tons of quartz and 4 tons of lime. The purge was carried out to obtain slag and rich matte.

When melting the melts by 60%, the processing of the next portion of the charge was lengthened and the smelting capacity decreased by 10%.

Example 7

30 tons of matte were poured into the SEC unit and the melt was blown with a carbon-air mixture with a coal content of 0.35 kg / m ³ and with a coal consumption of 500 kg / t of matte. In the process of blowing the melt with air enriched with oxygen up to 25% vol., 100 tons of concentrate were loaded, and after its melting 16 tons of quartz and 4 tons of lime. The purge was carried out to obtain slag and rich matte.

When melting the melts by 80%, the amount of the processed portion of the charge decreased by about 15% due to insufficient heat.

Thus, the implementation of the proposed method for the processing of sulfide copper-lead-zinc materials within the parameters specified in the claims allows to eliminate difficulties during smelting associated with the disposal of converter gases of complex composition, as well as with the heterogeneity of the melt in the converter.

Claims (1)

A method of processing sulfide copper-lead-zinc concentrate, which includes loading the concentrate into the converter and its oxidative smelting, characterized in that the matte is initially poured into the converter and blown with a carbon-air mixture with a coal flow rate of 500 kg / t matte with a volumetric ratio of coal to air 0, 35 kg / m ^3, the concentrate was charged on the surface of molten matte, the matte is then purged with oxygen enriched air up to 25 vol.%, to completely melt the concentrate was charged quartz and limestone flux and continue n oduvku ensuring the slag and matte rich in copper obtained rich slag and copper matte is added to 70% and the process is resumed with the processing of melt blowing uglevozdushnoy mixture.