RU2108403C1 - Method for production of copper-phosphorus alloying composition - Google Patents

Abstract

FIELD: nonferrous metallurgy, in particular, production of copper-phosphorus alloys. SUBSTANCE: method includes melting of copper under layer of slag and subsequent pouring of melt overheated 150-200 C above copper melting point into ladle on whose bottom elemental phosphorus is loaded and isolated from the surface with solid copper and metal melt is saturated with phosphorus in ladle. Liquid copper-slag ratio in slag-metal melt is maintained equal to 1:((0.05-0.10). Ratio of solid copper isolating the surface of elemental phosphorus loaded onto ladle bottom to liquid copper contained in slag-metal melt is (0.05-0.10):1. EFFECT: higher efficiency. 1 tbl

Description

 The invention relates to non-ferrous metallurgy, in particular to a technology for producing copper-phosphorus ligatures, which are used for deoxidation of copper, non-ferrous metal alloys and as solders.

 A known method [1] for producing a copper-phosphorus alloy, in which phosphorus is placed in an inverted crucible, mounted on a rod, by which it is introduced into molten copper and held until the reaction is completed. The method does not allow to obtain alloys with a high (more than 6%) phosphorus content, has a low productivity, is not used in industrial conditions.

 The known method [1], according to which the molten copper in metered portions enters a sealed reactor with elemental phosphorus. The method allows to obtain ligatures with a phosphorus content of up to 15 wt.%. The tightness of the reactor and the high partial pressure of phosphorus in it lead to an explosive process. In practice, not applicable.

 A known method [2], in which the vapor of phosphorus obtained by sublimation of phosphorus in electric furnaces from phosphate rock is introduced into molten copper. The method is complicated in hardware design and has difficult working conditions due to the use of gaseous phosphorus.

 A known method in which copper and phosphorus-containing waste phosphorus production is melted in an inert atmosphere [3] or with a reducing agent in air [4]. The methods are characterized by a high content of impurities in the ligature and a low yield of metal.

A known method for producing a copper-phosphorus alloy by melting a mixture consisting of copper and phosphorus [5]. Chips or copper scraps are mixed with red phosphorus and placed in a hermetically sealed iron pipe. The pipe is heated to 300 ^o C and maintained at this temperature for 4-6 hours. The formation of a copper-phosphorus alloy in this case occurs as a result of a diffusion process at relatively low temperatures without any fumes of phosphorus. In this way an alloy is obtained with a phosphorus content of up to 24-28%. The method is characterized by low productivity.

A known method for the production of copper-phosphorous alloy [5] (adopted as an analogue and prototype), in which copper is melted under a layer of slag. A mixture of soda ash and fluorspar is used as flux (approximately 8 kg of soda ash is consumed per 1000 kg of copper). Melted and superheated at 70 - 120 ^o C above the melting temperature, the copper is separated from the slag, covered with a layer of dry, well-burned charcoal and poured into a ladle lined with refractory clay. Previously, red phosphorus is loaded onto the bottom of the bucket, compacted, covered with a layer of dry wood sawdust 30-50 mm thick. Plates of copper or phosphorous copper are placed on the sawdust in the middle of the bucket for even distribution of liquid copper when it is drained into the bucket. After the complete dissolution of phosphorus in molten copper, the finished alloy is poured into flat open cast iron molds with a large number of pinches.

 The production of a copper-phosphorus alloy in this way is associated with loss of phosphorus on waste (the degree of assimilation of phosphorus is less than 85%) and a strong gas contamination of the workshop atmosphere.

 The objective of the invention is the creation of an environmentally friendly technology for the production of copper-phosphorus alloy by increasing the degree of use of phosphorus and reducing losses of phosphorus with gases.

This object is achieved in that in a method for producing copper-phosphorus ligature, comprising melting copper under a slag layer, followed by pouring the superheated melt into a ladle, to the bottom of which elemental phosphorus is loaded, insulated from the surface with solid copper, and the metal melt is saturated with phosphorus in the ladle, according to invention, wherein as the melt poured into a ladle are used resulting in the melting of copper under the layer of slag slag-metal melt is overheated at 150-200 ^o C above the melting point of copper, with maintaining m in it the ratio of liquid copper to slag 1: (0.05-0.10), respectively, while the ratio of solid copper insulating elemental phosphorus loaded to the bottom of the ladle from the surface to liquid copper contained in the slag metal melt is (0.05 -0.10): 1.

 New in the proposed technical solution is the simultaneous discharge of copper and slag from the furnace into elemental phosphorus and solid copper, thereby creating a reaction zone sealed and isolated from the surrounding atmosphere, as well as temperature ranges and component ratios ensuring the formation of a solid slag layer on the surface of the copper melt in the bucket before the reaction of copper and phosphorus.

 The expression of a positive effect (in comparison with the prototype) is a high 07.5-99.4% absorption of phosphorus by copper and less - up to 0.2% loss of phosphorus with gases.

 In the proposed technical solution, a higher absorption of phosphorus by copper and a decrease in its loss with gas is achieved due to the temperature regime and the sequence of crystallization of slag and melting of solid copper, which is determined by the ratio of components in the reaction space.

Initially, MO grade copper in the form of viber bars or cathodes (pure copper waste can be used) is melted in the furnace together with fluxes to produce slag based on the CaO-SiO ₂ -Na ₂ O system (preferably 10-20% Na ₂ , 20-30% CaO and 45-60% SiO ₂ ) with a melting point of 1100-1200 ^o C. As a flux, a block silicate, limestone, calcined lime, quartz sand and soda are used. The presence of slag in the furnace reduces the loss of copper during smelting. The number of fluxes is taken so that the ratio of liquid copper to slag corresponds to a ratio of 1: (0.05-0.10). This ratio is determined by the conditions for the saturation of copper with phosphorus during the discharge of melts from the furnace into the ladle. So reducing the amount of slag (slag / copper less than 0.05) does not provide a continuous coating layer of slag in the ladle. When the slag / copper ratio is more than 0.1, a thick slag layer in the ladle reduces the processability - the casting of the ligature into the molds becomes more complicated, and product losses increase.

The melting temperature - overheating of the melts at 150-200 ^o C above the melting point of copper, is determined by the need to drain the products from the furnace into the ladle in liquid form, separate the slag and copper into the ladle (settling), heat the ladle and melt the solid copper that covers the phosphorus layer, during which the temperature decreases by 100-150 ^o C. A decrease in the temperature of the superheat does not provide the temperature regime of saturation of copper with phosphorus, the degree of assimilation sharply decreases. The use of slag metal melts overheated above 200 ^o C above the melting point of copper to obtain a master alloy leads to premature melting of solid copper, the release of phosphorus to the surface of the melt, its intense oxidation in air, which also significantly reduces the degree of assimilation of phosphorus.

 An important role in the process is performed by solid copper, which insulates the surface of phosphorus in the ladle. The need to load it is associated with a small (in comparison with copper) specific gravity of phosphorus and its possible float to the surface with an insufficient amount of solid copper. Excess solid copper eliminates the reaction of liquid copper and phosphorus. The regulated ratio of solid copper in the ladle to liquid copper supplied to the ladle prevents reactions from occurring before the slag solidifies, thereby sealing the reaction volume. When the ratio of solid copper in the ladle to liquid copper is less than 0.05: 1, the incubation period is insufficient for the slag to solidify before the start of the reaction, and more than 0.1: 1 - it slows down the onset of reactions up to its complete cessation. In both cases, the degree of phosphorus uptake is reduced.

 It should be noted that all phosphorus that has surfaced on the melt surface or remains unreacted in the ladle (crucible), subsequently burns when it comes into contact with the atmosphere in the ladle or molds when casting the ligature into ingots. In all cases, not only the degree of phosphorus utilization is reduced, but the surrounding atmosphere is significantly polluted. Therefore, the creation of an environmentally friendly technology for the production of copper-phosphorus ligatures is an important and urgent task. No attempt has been found in patent and technological ligature to solve this problem by saturating liquid copper with phosphorus under a slag layer.

It should also be noted that the presence of heated slag above the reaction zone prevents the release of phosphorus oxide (P ₂ O ₅ ) into the atmosphere, the formation of which is possible due to the reaction of oxygen dissolved in liquid copper with phosphorus or ligature, as well as the oxidation of phosphorus by an oxygen-containing gas located between particles of solid phosphorus.

 The proposed method for the production of copper-phosphorus ligatures can be implemented by melting copper and fluxes in an arc, reflective or induction furnace, followed by overflow of the melts into a lined ladle (crucible) with elemental phosphorus loaded into it.

 The invention is tested and tested in the production of copper-phosphorus alloys of grades MF 9-11 according to GOST 4515-81.

 Information confirming the possibility of carrying out the invention.

Copper (MO) in the form of viber bars was smelted in a DSP-0.5 arc steelmaking furnace. Silicate block (2Na ₂ O-SiO ₂ ), silica sand (96% SiO ₂ ) and calcined lime (86% CaO) were taken as fluxes. The number of copper and fluxes loaded into the furnace is given in the table, experiment 1. Slag composition 60% SiO ₂ , 20% Na ₂ O and 20% CaO, which, according to the melting diagram, corresponds to its melting point 1100 ^o C. Upon reaching the furnace temperature 1230 ^o C (150 ^o C above the melting point of copper) slag metal melt (slag / liquid copper ratio is 0.1) was transferred from the furnace to a ladle lined with dinas, to the bottom of which 50 kg of elemental phosphorus was loaded in powder form (99.2% P, 0 , 54 P ₂ O ₅ ), top coated with plates of metallic copper with a total mass of 30 kg (ratio of copper in ladle / liquid and copper is 0.07). After the slag-metal melt was drained from the furnace into the ladle for 25 minutes, the mass was kept in the ladle, after which a hole was punched in the slag crust and copper-phosphor ligature was poured into the molds through it. The composition of the ligature was determined by chemical methods for the content of copper, phosphorus and impurities. The resulting ligature contained 9.6% phosphorus, 89.9% copper and 0.5% impurities. The degree of phosphorus utilization was 97.5%, and the loss of phosphorus with gases was 0.2%.

 The results of other experiments (tables) showed that the developed method allows to obtain ligatures of brands MF 9-11. The degree of assimilation of phosphorus is at least 97.5%. Losses of phosphorus with gases do not exceed 0.2-0.3%. The degree of phosphorus utilization was determined as the ratio of the amount of phosphorus in the ligature to the mass of the loaded phosphorus taking into account its purity, and the loss of phosphorus with gas as the difference between the loaded phosphorus and the assimilated ligature and slag.

 Outside the scope of the claims, the degree of phosphorus uptake is less than 76.4%, moreover, in experiments 9 and 10, unreacted phosphorus remained at the bottom of the bucket, and in experiments 7, 8 and 11, phosphorus was ejected and burned on the melt surface.

Claims (1)

A method of producing a copper-phosphorus ligature, comprising floating copper under a slag layer, followed by pouring the superheated melt into a ladle, on the bottom of which elemental phosphorus is loaded, insulated from the surface with solid copper, and saturation of the metal melt with phosphorus in the ladle, characterized in that it is merged into the melt ladle uses the slag-metal melt obtained by melting copper under a slag layer, which is superheated 150-200 ^° C higher than the melting temperature of copper, while maintaining the ratio of liquid copper to slag 1: (0.05 - 0.10) s responsibly, in this case, the ratio of solid copper insulating elemental phosphorus loaded to the bottom of the ladle from the surface to liquid copper contained in the slag-metal melt is (0.05 - 0.10): 1.

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