SU1421787A1 - Method of preparing secondary lead material to electric melting - Google Patents

Abstract

The invention is intended for the preparation of secondary lead raw materials for electric smelting. The aim of the invention is to protect the environment by eliminating the transfer of gummy organic substances to waste gases and reducing growth. Secondary lead raw materials, circulating dust (not less than 15%) and fluxes are mixed, dried to a residual moisture content of not more than 8%, and sulphite-yeast brewing with a density of 1.12-1.18 g / cm in quantity is applied to the granulator. 2.5-4% by dry weight. The rolled mixture is subjected to heat treatment to a residual moisture content of not more than 3% by blowing the coolant, for example air heated by flue gases, with a temperature of not more than 180 C from the bottom up through a layer of pellets when heated to a temperature not more than 130 P. 4 z.p, f-ly, 3 tab . "

Description

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This invention relates to non-ferrous metallurgy and can be used in the preparation of fine-grained secondary lead raw materials for smelting.

The purpose of the invention is to protect the environment by eliminating the release of gummy organic substances into waste gases and reducing dust-borne matter.

The method is carried out as follows.

Secondary lead raw materials, circulating materials (not less than 15%) and fluxes of the mixture in a given ratio are dried in a three-way drum to a residual moisture content of not more than 8% and shaken with the use of an aqueous solution of yeast-free yeast brew (SLW) with a density of 1 5, 12 -1.18 g / cm, set in the amount of 2.5-4.0% by dry mass. The pelleted charge from the granulator enters by gravity into the furnace unit, for example, an sintering machine, in which it is subjected to heat treatment to a residual moisture content of not more than 3% by blowing heat-transfer material, n (air heated by furnace) i) with a temperature of no more upwards through a two-strata layer of granules when heated to a temperature of not more than 1 30 ° С

After heat treatment, the granulated mixture is sent to electric smelting, and dusty gases are cleaned to remove g from dust.

Example I. The starting materials for the tests are:

sulphate-oxide part of battery scrap containing 9%: lead 68-71 copper 0, zinc 0.1-0.4; iron 0, 52-05b; sulfur 5.8-6.6 (total „) silicon dioxide I, 15-1.43; calcium oxide 0.63-0584; organic 4.5-5.5;

lead cake composition,%; lead 12-18.15 copper 0.35-0.6; zinc 4.5-5.2; iron 10.2-17.6; sulfur 10.64 - 12.69 (total); silica 10.3-17.5; calcium oxide 1-2;

. dust composition,%: lead 49,0-5554; copper 0,23-0,4 /; zinc 1.91-2.95; iron 0.17-2.67; cepai 7.28-9.44 (COMMON); silicon dioxide 0,23-1,28; calcium oxide 0.80-1.41.

limestone to a particle size of minus 6 mm and cocTaBaj% t calcium oxide 52.0-54.0 silicon dioxide iron OJ-O, 3.

0

Rolling is subjected to the mixture of the following composition,%:

Sulfate oxide portion62.5

Lead Cake 27.5

Known to 10.0

A reverse lead drink was added to the mixture in the amount of 5–20% and the mixture was thoroughly mixed using a grab bridge crane. The prepared mixture was dried in a tumble dryer with a diameter of 1.4 m and a length of 8 m and subjected to pelleting. A 5-cup granulator with a diameter of 2 m. At the same time as the mixture, an aqueous solution of a sulphite-yeast brew with a density of 1.12-1.18 g / cm was supplied to the pan granulator. Consumption of SDB is 0 l l 2,0-4,5% to the mixture by dry weight

Heat treatment of the granulated mixture was carried out on a continuously operating sintering machine with an area of 0.55 m blast chambers with heat-blown blower (heated air) bottom at a height of 120 mm pellets on the pallets and a speed of 50 mm / min. Of the heat carrier was 150 -190 С and heating of the granules led to a temperature of 90-150 С

In the process of drying the initial mixture, its pelleting and heat treatment of the granules, periodic sampling was carried out to determine their moisture content, grain size distribution and crush strength.

During heat treatment of the charge, the dust removal and the content of resinous substances in the exhaust gases were determined.

The tabLo shows the effect of the heat treatment temperature of the granulated mixture on the content of resinous organic matter in the vapor-gas phase (20% recycled dust added to the mixture; the initial humidity of the mixture was 15.2%; the humidity of the mixture before oxidation was 8%; the consumption of sulphite-yeast brew 2.5%; residual moisture of granules 1%; durability of heat-treated granules for crushing 13.1 kg / granule)

The display2 shows the effect of circulating dust consumption on the granulometric composition of the rounded charge (initial moisture content of 15.2%; moisture content of the charge before pelleting 8%; consumption of dry cooling material is 2.5% by dry weight; heat carrier temperature during heat treatment is 165 C; heating of granules during heat treatment 110 ° C; moisture content of the granules after

five

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five

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heat treatment 2%; granule strength 10.2 kg / granule)

Table 3 shows the test results for determining the consumption of the PSB of the steam pipe and the crush strength of the granules after heat treatment (added to the charge 20% of the circulating fluid; the moisture content of the initial slurry is 14.9%; the temperature of the coolant is 165 ° C; the heating temperature of the material is 90 ° C;

For comparison, tests were carried out in a known manner on the same composition of the initial mixture: drying the mixture in a tumble dryer, rolling it on a pan granulator using water, sintering the granulated mixture on an sinter machine.

From the data of Table 1-3, it can be seen that the heat treatment of the pre-dried granulated mixture with the addition of recycled dust and sulphite-yeast bark, compared with the known method, excluded the gummy organic substances into the gas phase and reduced dust removal. This will allow cleaning the gases and eliminating harmful emissions. substances into the environment.

Example2.3a balance period for 55 hours of continuous operation. processed 27589 kg of the charge. Test results: Amount of added circulating ingredient,%, to blend20

The moisture content of the mixture in the drying drum,%:

ho drying15,3

after drying7.8

Consumption of SDB,% of the dry weight of the mixture, 3.0 Content of granules with a particle size of + 10 mm in the granulated. Charge,% 61.7 Temperature, ° С: heat carrier during heat treatment of pellets 165 for heating pellets

during software heat treatment Consumption of heat carrier (air heated by flue gases), nm h1028

per 1 kg of dry granules 2.1. Humidity of granules,%: before heat treatment 10.87 after heat treatment 2.07 Specific productivity, t / m day: dry granules 21.9 in moisture content 2.21 Strength of dry granules in crushing, kg / granule 10.8

Pyshevynos,%

,, mass of charge1,2

Content of resinous organic matter in exhaust gases, mg / nm

According to the proposed method, the discharge of organic matter by the sintering of the charge as a result of pyrolysis of plastic components 1 {X5 to the atmosphere makes it possible to clean the gases from the pier, the dust removal during heat treatment and during their transportation is eliminated; cleaning the gas tract from a mixture of dust and resinous organic matter, improves sanitary conditions at workplaces.

In addition, during the subsequent electric smelting of the granulated charge, which has been heat treated, the productivity of the furnaces increases, the metal losses are reduced due to the reduction of dust removal, the consumption of electrical energy, electrodes and solid reducing agent is reduced due to an increase in the gas permeability of the granulated charge.

Claims (4)

Invention Formula 1 o A method of preparing secondary lead raw materials for electrical heating, including mixing lead containing raw materials, recycled materials and fluxes, coating with a binder and subsequent heat treatment of the granules, characterized in that, in order to protect the environment by eliminating the gummy resinous organic substances in waste gaseous gases and reduction of heat removal, heat treatment of the granules is carried out with a heat carrier with a temperature not exceeding 180 ° C and when the temperature of the granules is not higher than 130 ° C, 2. Method of pop, 1, characterized in that after mixing the mixture is dried to a moisture content of not more than 8% 3. The Popp method, 1 and 2, is distinguished by the fact that circulating dust in an amount of not less than 15% is introduced into the mixture. Sintering (agglomeration) of granulated mixture (known method) 735 620 810 Heat treatment of granulated mixture 150. 90 No 165 BY 180 130 190 150 4. Method according to any one of claims 1 to 3, characterized in that as a binder, a sulfite yeast brewing agent is used in an amount of 2.5-4% of the blend by dry weight. 5, the method according to claims 1-4, characterized in that the heat treatment of the granules is carried out to a residual humidity not more than 3%, 1 Table The mixture is caked, organic pyrolysis is underway The mixture does not ignite Not ten The mixture ignites spontaneously, organic pyrolysis occurs Sintering mix (pelleting on water) (known method) Sintering the mixture (a known method) 10 4.3 The mixture is sintered with improvement organic resin Heat treatment of granulated mixture table 2 Table 3