SU990844A1 - Method for processing zinc-bearing materials by rolling - Google Patents

Description

This invention relates to non-ferrous metallurgy, in particular to methods. processing of zinc-containing raw materials

There is a method of processing zinc-containing materials by valving, including blending them with coking and reducing firing obtained

charge tl3 "

However, a well-known method requires a high consumption of expensive coke - up to 35-55% by weight of zinc-containing raw materials, which leads to an increase in the cost of the process.

The high consumption of coke is associated with the fact that a considerable part of it (up to 30%) is consumed to absorb the liquid phase formed in the high-temperature zone, i.e. does not participate directly in the process of reduction of lead and zinc oxides to metals.

There is also known a method of processing zinc-containing pulpwood, including 1C blending them with coal and coking and reducing roasting of the resulting mixture C. However, the known method does not provide a significant reduction in coke, since coal burns out at an early stage of entrenching and therefore

can not serve as a sink. liquid

phases.

The purpose of the invention is to reduce the consumption of coke.

The goal is achieved by the fact that according to the method of processing zinc-containing materials by valance, including blending them with

10 with charcoal and coke and reduction firing of the resulting mixture, the loops are carried out using coke and spent thermal insulation of graphitization furnaces with a particle size of 2-10 mm.

15

In addition, the waste heat insulation of graphitization furnaces is introduced in an amount of 1.5-10% of the weight of the charge.

Claims (2)

The waste heat insulation, 20 as an absorber of the liquid phase, has the advantages of coking during velcevania, due to which partial replacement of coke in the charge is possible while maintaining the furnace productivity and product quality at the same level 25. The waste heat insulation compared with coking is characterized by an increased adsorption capacity for the liquid (molten) phase. This is due to the fact that poris30. The density and specific surface of particles are thermally insulated higher than coke. The adsorption capacity of stone coking coal O fraction, 5-6 mm is 11.5 mg / g, and in the spent heat insulation of the same fractional composition 15.4 mg / g. In addition, waste heat insulation is also characterized by reduced reactivity with respect to metal oxides, oxygen, and carbon dioxide. With reactivity, it is 0.55-0.8 and 0.9-2.7 for thermal insulation and coke, respectively. In connection with the noted features, thermal insulation is a very effective substitute for coke, in particular, the part of it that absorbs the liquid phase. To be used in the charge, the Weltzp thermal insulation needs to be clifed with a sifter less than 2 mm, containing mineral impurities, and a large fraction of more than 10 m. A fraction less than 2 mm turns into sublimates, which makes it difficult for them to further hydrometallurgical recycling. As for the vertex size limit (10 mm), it is chosen from the conditions that ensure good contact of the charge components and thermal insulation. Thermal insulation particles less than 10 mm in size are better and more evenly distributed in the charge, they more intensively reduce metal oxides and more fully absorb the molten part of the charge, as a result of which the elevation process is accelerated. In addition, the established limits on the size of thermal insulation guarantee its lower consumption. The size of the zinc-containing components of the mixture is usually 10-15 mm. When introducing spent thermal insulation into the charge for processing zinc-containing materials and graphitization furnaces, the process of valtzing proceeds in the following mode. The first third of the length of the furnace, counting from the charging end (temperature to), is followed by the processes of drying, heating and partial reduction of metal oxides. At the same time, 8–10% of coke burns (the burn-out rate is 0.35–0.48 kg / m of the furnace length), which ensures the heat output of the furnace by about 3-5%. A minor part of it goes to the restoration of zinc compounds. Due to its low content in the mass to be treated and its low reactivity, the waste heat insulation practically does not burn out and does not waste on restoration. In the reaction zone (maximum temperature IBOO C), reduction processes are developed and terminated. Their flow is mainly provided by coking, both in, due to its higher reactivity, and in quantity, in the charge. Particles of thermal izo-, ltion are also involved in the reduction of oxides. However, their main role is to absorb the liquid phase. This is due to the higher adsorption capacity of heat insulating particles than that of coke particles. It is important to note that the amount of waste thermal insulation introduced into the velcevana furnace is dependent on the degree of its development in the process of graphitization. If the reactivity of waste thermal insulation and coke is significantly different, for example, by a factor of 2 to 3, then only partial replacement of coke, which is consumed to absorb the liquid phase, is possible. A further increase in the thermal insulation content in the charge leads to a decrease in furnace performance, due to the deterioration of metal oxide reduction. In the case where the reactivity of the waste thermal insulation and coke are close, a complete replacement of coke consumed for absorption of the liquid phase is possible. Examples The tests are carried out in a Veltsev kiln having a length of 5 m and an internal diameter of 0.8 m. The charge components are zinc cake (wt.%; Zinc 21.1; lead 1.9; cadmium 0.3; copper 3,3 ; iron 24.5, sulfur 6.5), toxic (wt.%: carbon 84.6; ash 12.8; d ee 1,2) and waste heat insulation of graphitization furnaces (wt.%: carbon 72.4 ; ash 18.8; volatile - absent). Before being fed into the furnace, thermal insulation is classified with a screening fraction of less than 2 mm and more than 10 mm. The reactivity of coke is 0.93, and the waste heat insulation is 0.64. The test results are presented in the table. As can be seen, with the introduction of 2% waste heat insulation of graphitization furnaces of the 2-10 mm fraction into the charge, the consumption of coke, related to the weight of zinc cake, is reduced by 2.7 abs.% Compared to the KOHT trial experiment 1. At the same time, no visible deviations from the normal mode of valtzing were found: the furnace performance (in sublimation), the quality of sublimates do not differ from the usual ones. The application of the proposed method of processing zinc-containing materials by valching allows one to exclude from the process that part of the deficient coke which is consumed for the absorption of the forming liquid phase. In addition, it becomes possible to use significant amounts of waste from electrode production, in particular, waste heat insulation of graphitization furnaces, which are not completely recovered in this time. Claim 1. Method of processing zinc-containing materials by valchting, including blending them with coal and coking and restoring roasting of the resulting mixture, characterized in that, in order to reduce the consumption of coke, veel-cutting is performed using a mixture of coke and spent thermal insulation, graphite furnaces; with a particle size of 2-10 mm. 2. A method according to claim 1, characterized in that the waste heat insulation of graphitization furnaces is introduced in an amount of 1.5-10% of. weight of the charge. Sources of information taken into account in the examination 1. N. Gudima, V. Shane. A brief guide to metallurgy of non-ferrous metals. M., Metallurgy, 1975, p.328. 2. Lakernik M.M. , Pakhomova G.N. Zinc and cadmium hydrometallurgists. M., Metallurgists, 1969, p. 398-400.