RU2407811C1 - Procedure for re-melting copper scrap and production of brass and bronze and furnace for implementation of this procedure - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: procedure consists in charging pressed blocks of scrap into crucible of furnace, in heating charged raw material to temperature exceeding temperature of melt by 100°C, and in casting copper melt into moulds. Also, height of copper melt in the crucible of the furnace is maintained at 1000 mm. At copper melt casting first the upper layer of copper melt corresponding to 5-10 % of weight of total melt in the crucible of the furnace is cast into a ladle or chute wherefrom melt is cast into moulds to receive weight of 500 kg. Further, 80-90 % of copper melt is cast from the middle part of the crucible of the furnace into the moulds for production of ingots of 19-25 kg weight. Finally, copper melt left on the bottom of the furnace crucible and corresponding to 5-10 % of while weight of melt is cast into the ladle or chute. The furnace consists of a case, of lining out of a refractory brick, of the crucible for re-melting raw material charged into the furnace, of a removable cover of the crucible, and of three notches positioned at crucible height. Also, the lower notch is positioned at the level of the bottom of the furnace crucible, the middle notch is at height of 80 mm from the bottom of the furnace and the upper notch is at height of 900 mm from the bottom of the furnace. The furnace is equipped with gas dead-end burners arranged in chambers separated from crucible space with brickwork out of refractory brick. Channels are made along whole height of brickwork.

EFFECT: production of high quality copper, brass and bronze with low capital expenditures and low prime cost of products.

3 cl, 2 dwg, 1 tbl

Description

The present invention relates to the field of non-ferrous metallurgy, in particular to a method for smelting copper scrap, producing brass and bronze, and to a furnace device for implementing this method.

A known method and installation for processing cages or waste non-ferrous metals and their alloys (RU 2007101902 A, 09/10/2008. Bull. 25, C22B 1/216 (2006, 01), Cruz A.K., Bender O.V.), consisting in loading scrap or dross into a horizontal rotary kiln, melting and rotating heated material, and removing liquid metal. Heating is carried out in an atmosphere of noble gases, or nitrogen, or hydrogen, or methane, or carbon monoxide, or carbon dioxide, or oxygen, or air, or mixtures thereof using an open convective electric arc. The electrode performs the function of a cathode in a direct current electric circuit, and recycled material or scrap, or the bottom of the furnace capacity, is used as an anode. Contaminated scrap or waste containing organic materials is treated without using a convective arc, and the organics formed are removed from the furnace.

The disadvantages of the known method and installation for the treatment of cages or non-ferrous metal wastes are complex hardware design, which includes an additional facility for trapping and neutralizing organic vapors. The process of separation of the resulting non-ferrous metal melt and its impurities is not provided. The furnace design does not provide for periodic cleaning of the inner surface of the lining from layering impurities (nastilya).

All these shortcomings lead to an increase in capital and operating costs.

Known rotary melting furnace for processing non-ferrous metal waste (RU 2171437 C1, 07.27.2001, F27B 7/00, C22B 7/00, 21/00, Sharud A.N., Makarov E.F.), containing a cylindrical body, burner a device, a tap hole for draining molten metal and a tap hole for draining slag located on the cylindrical part of the body on one axis.

The disadvantages of the known rotary kiln are increased energy costs (electricity, natural gas) per ton of product obtained, a small utilization rate of the useful volume of the furnace (0.35), and complicated hardware design.

All these shortcomings lead to an increase in capital and operating costs.

The closest analogue with respect to the claimed method of smelting copper scrap and obtaining brass and bronze and a furnace for implementing the method is the method of primary processing of complex scrap and mixed non-ferrous metal waste and installation for its implementation (RU 2082784 C1, 27.06 / 1997, C22B 7/00 , F27B 1/09, Popov G.P., Shamarin B.V., Kudimov A.G., Kirichenko V.F.) The method includes fragmentation of the feedstock, transportation, firing with burning of combustible materials with the removal of gases for cleaning, melting with separation of products, slag and ash. The heat treatment of the feedstock is carried out in an inert atmosphere, first at 800 - 900 ° C with the separation of lead and aluminum, and then at 1200 - 1250 ° C with the separation of copper using gold and silver. The installation contains a fragmentation unit of the feedstock. An electric firing and melting furnace, equipped with a device for moving fragments of the feedstock and removing molten non-ferrous metals and a cooling chamber in communication with the firing and melting furnace, comprises a device for neutralizing and purifying gases. The installation is equipped with a closed rail system.

The advantages of the prototype include the fact that the method and installation allow the primary processing of complex scrap and complex waste, as well as the fact that it provides for the melting and separation of non-ferrous metals.

The disadvantages of the method and installation are the complexity and cumbersome technology and design of the installation, when the non-ferrous metal melt drains from the inclined pallet, the trolleys will be captured by impurities and contaminate the product, significant capital and operating costs are required.

The objectives of the invention are to improve the quality of the products obtained, reduce losses of raw materials containing non-ferrous metals, reduce energy costs (electricity, natural gas), create safe working conditions, reduce the cost of manufactured products, simplify the design of the furnace, simplify the process operations.

These tasks are achieved in that the height of the copper melt in the crucible of the furnace is maintained equal to 1000 mm, while in casting the molten copper, the upper layer of copper melt, which is equal to 5-10% of the total melt in the crucible of the furnace, is first poured into the ladle or trough , from which the melt is poured into the molds to obtain a mass of 500 kg, then 80-90% of the copper melt from the middle part of the crucible of the furnace is poured into the molds to obtain ingots weighing 19-25 kg, and the copper melt remaining at the bottom of the crucible of the furnace is finally drained, comprising 5 -10% of the total mass of the melt in the bucket or the trough from which the melt is poured into the molds to obtain blocks weighing 500 kg The casting of a melt of copper, brass or bronze is carried out after holding it for one hour when the set temperature of the melts is reached.

The non-ferrous metal blocks obtained by draining the melt from the top of the crucible of the furnace, and the non-ferrous metal blocks obtained by draining the melt remaining at the bottom of the crucible of the furnace are accumulated and then separately re-melted in the same furnace.

The furnace is shown in FIG. 1 (front view) and FIG. 2 (top view). The furnace includes: a steel casing of the furnace (not shown), a lining of the furnace (FIGS. 1 and 2, item 1), chambers for gas dead-end burners (FIGS. 1 and 2, position 2), gas dead-end burners (FIG. 1 and 2, pos. 3), supports of dead-end burners (Fig. 1, pos. 4), nozzles for introducing natural gas into dead-end burners (Fig. 1, pos. 5), nozzles for discharging combustion products of natural gas (Fig. 1, pos. 6), channels for outputting natural gas combustion products from gas blind burners through pipelines to the exhaust pipe (Fig. 1, pos. 7), furnace crucible (Fig. 1, 2, pos. 8), channels in the furnace crucible for races non-ferrous metals or alloys thereof from the crucible space to the chamber space and vice versa (Fig. 1, 2, item 9), a tap hole for draining non-ferrous metal melt or their alloys contaminated with lightweight impurities into a special bucket or trough (Fig. 1, pos. .10), a tap hole for draining a non-ferrous metal melt or their alloys into a bucket or trough (Fig. 1, item 11), a tap hole for draining a non-ferrous metal melt or their alloys contaminated with heavy impurities in a bucket or trough (Fig. 1, pos. 12), the crucible cover of the furnace (Fig. 1, pos. 13), rings for removing the cover of the crucible of the furnace during loading og raw materials (figure 1, item 14).

The furnace has three slots located along the height of the crucible of the furnace in the following order:

- lower notch (figure 1, item 12) - at the bottom of the crucible bottom of the furnace;

- the average letka (figure 1, item 11) is located at a height of 80 mm from the bottom of the crucible furnace;

- the upper notch (figure 1, position 10) is located at a height of 900 mm from the bottom of the crucible of the furnace.

The channels in the furnace crucible (FIGS. 1, 2, item 9) provide the flow of the non-ferrous metal melt from the furnace crucible to the chambers, and thereby provide intensive heat transfer from gas dead ends to the non-ferrous metal melt in the furnace crucible. The same channels provide convection from non-ferrous metal melt in the chambers and crucible of the furnace from the bottom up.

The set of features of the proposed technical solution - the method of smelting copper scrap and producing brass or bronze and a furnace for implementing the method - differs from the prototype and should not be explicitly studied from the prior art, therefore, the author believes that the method and furnace for implementing the method are new and have inventive level.

The method of smelting copper scrap and producing brass and bronze and a furnace for implementing the method allow the production of copper, brass or bronze at cost, reduce energy costs (electricity, natural gas), create safe working conditions, obtain high-quality copper, brass and bronze with minimum capital and operating costs.

The method of smelting copper scrap and obtaining brass and bronze is as follows.

To implement the method, the furnace shown in Figs. 1 and 2 is used. Scrap of copper is subjected to selection to remove flammable substances (wood, plastic, rubber) and pressed into blocks weighing 500 kg. Remove the lid from the crucible of the furnace and load copper scrap blocks into it using a crane beam and special grippers. If you need to get brass or bronze, then in the crucible of the furnace also using a crane beam and a stand with an open bottom, load the ingots of copper and zinc in a certain mass ratio to obtain brass or ingots of copper and tin in a certain mass ratio to obtain bronzes. The raw materials are loaded into the furnace in such a way that the resulting copper, brass or bronze melts have a height in the crucible of the furnace equal to 1000 mm.

The lid (Fig. 1, pos. 13) is mounted on the crucible. Turn on deadlock gas burners (Fig. 1, item 3). The crucible of the furnace (Fig. 1, 2, item 8) is heated until the copper scrap or feedstock is completely melted to obtain brass or bronze. The heating of the melt of copper, brass or bronze is continued until the melt temperature is reached 100 ° C higher than the melting temperature of copper, brass or bronze and the melt is held at this temperature for 1 hour. After that, the upper layer of the molten copper, or brass, or bronze is poured through the notch (Fig. 1, item 10) into a special bucket or trough, from which the melt is sent to the molds with the formation of blocks weighing 500 kg.

These blocks of copper, or brass, or bronze are contaminated with lightweight impurities and therefore must be remelted. Then the middle layer of the molten copper, or brass, or bronze, containing minor impurities in the form of intermetallic compounds, is poured through the notch (Fig. 1, item 11) into the molds with the formation of ingots weighing 19-25 kg.

These ingots are used as commercial products. And, finally, the melt layer of copper, or brass, or bronze, remaining at the bottom of the crucible of the furnace, is poured through the notch (Fig. 1, item 12) into the molds with the formation of blocks weighing 500 kg. The lower layer of molten copper, or brass, or bronze is contaminated with heavy impurities and therefore must be remelted.

When copper and tin ingots are loaded into the crucible in certain mass ratios to obtain bronzes or copper and zinc ingots in certain mass ratios to produce brass, the mixing of bronze or brass melts will be carried out by convection of the melts through the underlying channels in the laying of the crucible from the space chambers for dead-end gas burners into the crucible space of the furnace and the upper layers of the melt; in the upper layers, the melt will flow through the upper channels of the crucible masonry into the dead-end gas chambers approx.

This movement of the melt flows will continue until the temperatures of the melts in the chambers and crucible of the furnace are equalized. This phenomenon is explained by the fact that the surface temperatures of dead-end burners in the lower part are higher than in the upper part. Convection of copper melts, or brass, or bronzes facilitates the distribution of lightweight impurities in the upper part, heavy in the lower part of the furnace crucible and the homogenization of the composition of the melts in the middle part of the crucible.

The results of the technological process of the proposed method for remelting scrap copper are presented in the table.

Claims (3)

1. A method of smelting copper scrap, comprising loading pressed blocks of copper scrap into a crucible of a furnace, heating the loaded scrap to a temperature above the melting point of 100 ° C, casting copper melt into molds, characterized in that the height of the copper melt in the crucible of the furnace is maintained at 1000 mm, in this case, when casting a copper melt, the upper layer of copper melt, which is equal to 5-10% of the mass of the total melt in the furnace crucible, is first poured from the crucible into a ladle or trough, from which the melt is poured into molds to obtain blocks weighing 500 kg, then 80- 90% melt di from the middle part of the crucible of the furnace into the molds to obtain ingots weighing 19-25 kg and finally pour the copper melt remaining at the bottom of the crucible furnace, comprising 5-10% of the total mass of the melt, into a ladle or trough, from which the melt is poured into the molds for obtaining blocks weighing 500 kg 2. The method according to claim 1, characterized in that after adjusting the temperature of the copper melt to a predetermined value in the crucible of the furnace, it is held for one hour until the melt is cast into the molds. 3. A furnace for smelting scrap of copper, containing a casing, refractory brick lining, a crucible for smelting scrap loaded into the furnace, a removable crucible lid, characterized in that it is capable of maintaining the height of the melt in the crucible of 1000 mm, has three slots located along the height of the crucible of the furnace, while the lower notch is located at the bottom of the crucible of the furnace, the average notch is at a height of 80 mm from the bottom of the furnace and the upper notch is at a height of 900 mm from the bottom of the furnace, and is equipped with gas dead-end burners located in chambers separated from the space tig For the furnace, masonry made of refractory bricks, in which channels are made along its entire height.

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