SU1488336A1 - Method of fuming lead-zinc slags - Google Patents

Description

The invention relates to non-ferrous metallurgy and can be used2

BUT to extract metals from slags by fusing. The goal is to increase the process performance and reduce costs. The method includes a two-stage blown slag melt with a carbonaceous reducing agent mixed with air, oxidizing lead and zinc vapors over the slag bath and trapping sublimates. Moreover, the first stage is carried out in a neutral mode with an air excess factor of 0.95-1.0, the second - in a reductive mode with an air excess factor of 0.8-0.9, and Each stage _{with a} purge is carried out in different sections of a dust collector.

The invention relates to non-ferrous metallurgy, in particular, to methods for extracting metals from metallurgical slags.

The purpose of the invention is to increase the productivity of the process and reduce costs.

The proposed method is characterized by the fact that the fuming process is carried out in one unit in two stages neutral with an excess air ratio of 0.95-1.0 for stripping lead and reducing with an excess air ratio of 0.8-0.9 for stripping zinc, and trapping sublimates at each stage of the purge is carried out in different sections of the dust collector.

The implementation of the method involves the use of two single slag-sublimation furnaces, which can significantly reduce costs during operation and repair.

The neutral purge mode in the first stage of the process provides a high rate of lead stripping with limited evaporation from the zinc melt and prevents thickening of the melt due to the formation of netite.

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Reduction in excess ratio

air below 0.95 reduces speed

lead stripping as lead is reduced to metallic 3

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anatomy that leads to a decrease in pro-. performance.

An increase in the excess air ratio above 1.0 contributes to the distillation of lead, but leads to the formation of magnetite due to slag over-oxidation, which leads to thickening of the melt, a decrease in the absorption of the blast and, consequently, to a decrease in productivity. | θ

The reduction mode of the purge in the second stage intensifies the reduction of zinc oxide and increases its evaporation rate, while completely suppressing the formation of magnetite.

Reducing the coefficient of excess air at the reduction stage below 0.8 leads to a decrease in the temperature of combustion of carbonaceous fuel, which causes a decrease in temperature, melt and worsens the conditions of distillation.

An increase in the excess air coefficient above 0.9 reduces the rate of zinc oxide reduction, and, consequently, the rate of its distillation, i.e. process performance.

Separate trapping of lead and zinc sublimates is achieved by the fact that part of the dust collector sections are assigned to the first stage of the process, i.e. It is included only for the time of capturing lead sublimates, and some sections are assigned to the second stage of the process, i.e. turns on only on. zinc trapping time. ^ 5 At that, separate sections of the dust collector, if necessary, can be used at both stages of the process to obtain a certain amount of collective lead-zinc sublimates. The number of sections assigned to each stage of the purge is determined by the volume of gas to be cleaned at this stage, their temperature and dustiness and throughput of a particular group of sections.

The process is as follows.

80-100 tons of molten lead-zinc / coke slag are poured into a slag-raising furnace from a shaft furnace for the smelting reduction of lead sinter or from heated slag settlers and purge it in a neutral blow mode at an excess air ratio of 0.95 for 30-40 minutes -1.0. At this time part

dust collector sections (for example, half of their total number) are open to trap lead voids. • New, and the rest closed. Then, at the end of the neutral stage of purging, the group of dust collector sections that captured lead sublimates overlap, and the group of sections is opened to trap zinc sublimates and lead to the second, reconstructive stage of blowing during 80-90 minutes with an excess air ratio of 0.8 to 0.9. At the end of the second stage of the purge, the blown slag is drained from the furnace and the dust collector sections are freed from sublimates into separate hoppers for lead and zinc sublimates, after which the purge cycle is repeated. The total duration of both stages of the process is 120–130 min.

With limited capacity of the dust collector, the total number of its sections may be insufficient to divide them into two groups for autonomous maintenance of each stage of the process. In this case, a dust collection scheme with partial selection is used, which involves the operation of some sections continuously during both stages of blowing to obtain collective lead-zinc sublimates.

So, in the case when the total number of sections of the dust collector is equal to six to ensure the required degree of purification of the gas stream entering after purging, at least four sections need to work. To do this, at the neutral stage of purging include sections No. 1,2,3,4, and at the recovery stage - sections No. 3,4,5,6. In sections 1 and 2, lead sublimates are caught, in sections 5 and 6, zinc sublimates, and in sections 3 and 4, collective lead-zinc sublimates.

Example 1. In the slag overheating furnace pour 86 tons of pork containing 2.3% lead and 16.3% zinc. The first, neutral stage of purging is carried out for 40 minutes with an air excess factor of 1.0, and the second, recovery stage - within * 80 minutes with an air excess factor of 0.9. Lead sublimates are captured in the first four sections of bag filters of the URFM-2 type dust collection unit,

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and the capture of zinc sublimates — stages — zinc sublimates, and in sections four of the same sections Nos. 3 and 4 in stages 1 and 2 - count

installation. 4.3 g of lead sublimates containing 38.62 lead and

31.52 zinc and 16 tons of zinc sublimates containing 71.42 zinc and 1.62 lead.

Example 2. In the slag distillation furnace pour 95 tons of pork containing 1.72 lead and 15.52 zinc. At the first stage of purging (40 minutes), the coefficient of excess air is 1.0, at the second (80 minutes) it is 0.8. The scheme for collecting dust from sublimates is similar to Example 1. • 3.3 tons of lead sublimates were obtained, 15 containing 37.32 lead and 34.52 zinc and 17 tons zinc sublimation containing 72.72 zinc and 1.22 lead.

Example 3. In the slag distillation furnace pour 86 tons of pork containing 20 1,482 lead and 14,62 zinc. At the first stage of purging (35 minutes), the excess air ratio is 0.95, at the second (80 min) it is 0.9. The scheme for catching sublimates is similar to Example 1. 2.6 tons of lead sublimates containing 35.92 lead and 33.72 zinc and 14 tons of zinc sublimates containing 72.962 zinc and 1.32 lead were obtained.

Example 4. 95 tons of slag containing 1.82 of lead and 16.62 of zinc are poured into the slag-slug 30 furnace. At the first stage of blowing (35 minutes), the excess air ratio is 0.95, at the second (80 minutes) it is 0.8. The scheme for capturing voz-35 gons is similar to Example 1. 3.2 t of lead sublimates were obtained containing 352 lead and 36.942 zinc and

18.5 tons of zinc sublimates containing 74.22 zinc and 1.52 lead. 40

Example 5. 86 tons of pork containing 1,542 lead and 14,32 zinc are poured into the slag overheating furnace. At the first stage of purging (40 minutes), the excess air ratio is 0.97, at the second 45 (80 minutes) - 0.85. The scheme for capturing sublimates is similar to Example 1. 2.6 tons of lead sublimates were obtained containing 36.22 lead and 30.762 zinc and

13.5 zinc sublimates containing βθ

72.52 zinc and 1,452 lead.

Example 6. The method is carried out in the conditions of example 1 except that the capture of sublimates is carried out in six sections of the dust collector. In sections 1 and 2 of the catch, lead sublimates are poured in the first neutral stage of the purge; in sections 5 and 6, the second, reducing stage

selective lead-zinc sublimates. 2.1 tons of lead sublimates containing 38.62 lead and 31.52 zinc, 8 tons of zinc sublimates containing 71.42 zinc and 1.62 lead and 10 tons of lead-zinc sublimates containing 9.42 lead and 63, were obtained 52 zinc.

Example 7. The method is carried out in the conditions of example 5, except that the capture sublimates is carried out in six sections of the dust collector.

In section 1, lead sublimates are caught at the first stage of purging, zinc sublimates are captured in section 6 of the second stage of purging, and collective lead-zinc sublimates are captured in sections Nos. 2,3,4 and 5. 0.7 tons of lead sublimates containing 36:, 22 lead and 30.72 zinc, 3.4 tons of zinc sublimates with a content of 72.52 zinc and 1.452 lead and 12.3 tons of lead-zinc sublimation with a content of 6.952 lead and 63.82 zinc.

The use of the proposed method of slag fuming provides, in comparison with the known methods, an increase in the extraction of lead and a reduction in the cost of purging.

The proposed method of fuming slags allows to obtain zinc sublimates containing 71-742 zinc (89-932 zinc oxide) and 1-22 lead, which, without any further processing, can be used as a starting product in a number of industries, for example, for the manufacture of paints on zinc based. Production of high-quality zinc sublimates allows to exclude the costs of additional purification of sublimates, i.e. reduce the cost of the process as a whole.

Claims (1)

Claim Method of fuming of lead-zinc spackles, including two-stage blowing of slag melt with carbonaceous reducing agent mixed with air, oxidation of lead and zinc vapors above the slag bath, cooling of gases and separate trapping of lead and zinc sublimates, which is caused by the fact that, in order to increase productivity 7 1488336 eight process and reduce costs, the first stage of the purging process is conducted in a neutral mode with an air excess factor of 0.95-1.0, the second stage is carried out in the same unit in a recovery mode with an air excess factor of 0.8-0.9 for the distillation of zinc, and trapping sublimates at each stage of the purge produced in different sections of the dust collector, and separate sections can be used at both stages of the purge.