Vacuum distillation furnace and method for producing high purity copper

Abstract

The application belongs to the technical field of nonferrous metallurgy, and particularly discloses a vacuum distillation furnace and a method for preparing high-purity copper. The vacuum distillation furnace comprises an evaporation furnace, a condensation furnace and an air duct. The upper part and the bottom part of the evaporation furnace body of the evaporation furnace are respectively provided with a feeding opening and a slag discharge opening. The evaporation furnace body is provided with a heating unit and a top cover at the top end. The top end of the condensation furnace body is provided with a vacuum pipe, and the upper part and / or the middle part of the condensation furnace body are respectively provided with a plurality of chromium plates from top to bottom. The condensation furnace body is sequentially and intermittently provided with a side heating structure, a condensation plate and a condensation collection plate below the bottom chromium plate. The top of the evaporation furnace body is provided with an air outlet, and the top of the condensation furnace body is provided with an air inlet above the top chromium plate. The air duct is connected with the air outlet of the evaporation furnace and the air inlet of the condensation furnace. The method comprises the steps of raw material heating, air duct control, steam impurity removal and high-purity copper collection. The application has the characteristics of compact structure, low energy consumption, high rectification efficiency, good impurity removal effect and high purity of rectification products.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-ferrous metallurgy, in particular to a vacuum distillation furnace with compact structure, low energy consumption, high rectification efficiency, good impurity removal effect and high purity of rectification products, and a method for preparing high-purity copper. BACKGROUND

[0002] High-purity copper is widely used in electronic, communication, superconducting, aerospace and other cutting-edge technology fields due to its low resistivity and high electromagnetic properties, and has achieved good results.

[0003] At present, the main high-purity copper refining technologies include electrolytic refining, electron beam melting, directional solidification, anion exchange and zone melting. Among them, electrolytic refining is effective for almost all impurities except oxygen, and is strict in requirements for electrolyte; electron beam melting is mainly effective for impurity elements with higher saturated vapor pressure than copper, such as Ag, Se, Te, S, Bi, Pb, etc., and has limited effect on other elements; anion exchange method removes impurity ions in copper solution through ion exchange, and then evaporates the solution to obtain high-purity CuCl2 and reduces it to obtain high-purity copper, which has a complex process flow and is difficult to mass-produce large copper ingots; zone melting is mainly effective for impurities with a segregation coefficient far from 1, but has limited effect on impurities with a segregation coefficient close to 1, and has low purification efficiency; directional solidification is mainly used for copper continuous casting and single crystal preparation, but for some metal and non-metal impurities with a segregation coefficient close to 1, multiple directional solidification is needed for purification, which will significantly increase the production cost and cause great environmental pressure.

[0004] Vacuum distillation is a common metallurgical method for smelting, refining and purification under reduced pressure, mainly by utilizing the difference in boiling points and saturated vapor pressures of different metals. The existing vacuum distillation furnace is mainly in the form of single hearth, which heats the metal at the bottom and controls the temperature difference in the vertical direction to obtain liquid metals with different boiling points. Since it needs to be distilled in a vacuum state, the furnace needs to be cooled and opened for charging and discharging, which not only cannot continuously process materials, but also has low processing efficiency and high energy consumption, and it is difficult to remove impurity elements with boiling points close to copper, resulting in poor purification effect. Therefore, in the prior art, a chromium volatilization hole plate is arranged between the condensing disc and the evaporation chamber of the furnace chamber, the high-temperature steam flows through the through holes of the hole plate, the gas passage is narrowed, the gas flow is increased, the amount of mist released per unit time is increased to reduce the particle size, and the impurity elements such as Fe, Si, Mn, Al and Cl react with the chromium hole plate at high temperature to generate reaction products adsorbed on the hole plate to remove impurities and improve purity, but the problems of non-continuous material processing, low processing efficiency and high energy consumption still exist.

[0005] In order to solve the problem that the single-hearth vacuum distillation furnace cannot realize large-batch metal distillation, the prior art adopts a horizontal structure to connect the distillation chamber and the condensation chamber side by side to form a double-hearth structure, and graphite electrodes are arranged inside the distillation chamber and the condensation chamber for heating, then a vapor passage is arranged between the distillation chamber and the condensation chamber and a ceramic mesh plate is arranged inside the vapor passage, so as to form a certain temperature gradient in the vapor passage to improve the purity of the product; however, since the graphite electrode heating limits the addition and removal of materials in a molten state, the application range is limited, and the condensation efficiency is low and the separation of multiple metals cannot be realized by condensing high-temperature vapor through the condensation wall in the condensation chamber. Therefore, in the prior art, the evaporation furnace and the condensation furnace are separated to form a double-hearth structure, and the middle part of the evaporation furnace and the condensation furnace is connected by a gas passage with different forms, which not only reduces energy consumption, but also separates substances with different boiling points through the gas passage with different structures, so as to realize efficient separation and rectification; and the condensation furnace adopts a multi-stage condensation chamber design on the side heating upper part to increase the temperature gradient change, so that different metals can be condensed and collected in the corresponding condensation chamber to realize the separation and collection and purification of multiple metals. However, since the structure of the gas passage is fixed, the gas passage with the corresponding structure can only be selected and used before the furnace is opened, and the opening size of the gas passage cannot be flexibly adjusted and closed during the vacuum distillation process, so that dynamic and efficient rectification cannot be realized, and the evaporation furnace and the condensation furnace cannot be completely isolated due to the inability to close the gas passage, so that continuous high-temperature distillation cannot be realized; and the fixed structure of the gas passage requires multiple gas passages, which increases the cost and management difficulty. In addition, since the gas passage connects the middle part of the evaporation furnace and the condensation furnace, the high-temperature vapor in the evaporation furnace needs a guide structure and additional heating structure to flow into the passage, and the vapor is also easy to accumulate in large quantities at the top of the evaporation furnace, thereby increasing the complexity of the structure and causing an increase in energy consumption. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides a vacuum distillation furnace with compact structure, low energy consumption, high rectification efficiency, good impurity removal effect and high purity of rectification products, and a method for preparing high-purity copper based on the vacuum distillation furnace.

[0007] The vacuum distillation furnace of the present application is realized as follows: comprising an evaporation furnace, a condensation furnace and a gas passage, the evaporation furnace comprises an evaporation furnace body, the upper part and the bottom part of the evaporation furnace body are respectively provided with a charging port and a slag discharge port which can communicate with the inside and outside, the side part, the upper part and / or the bottom part of the evaporation furnace body are provided with a heating unit, and the top end of the evaporation furnace body is detachably provided with a top cover.

[0008] The condensing furnace comprises a condensing furnace body, a vacuum pipe is arranged at the top end of the condensing furnace body and communicates with a vacuum system, a plurality of transverse chromium plates are arranged at the upper portion and / or the middle portion of the condensing furnace body in a spaced manner from top to bottom, and a side heating structure, a condensing plate and a condensing collection plate are sequentially and spacedly arranged below the bottom chromium plate.

[0009] The top of the evaporation furnace body is provided with an air outlet, the top of the condensing furnace body is provided with an air inlet above the top chromium plate, and the air duct communicates the air outlet of the evaporation furnace with the air inlet of the condensing furnace.

[0010] Further, a controllable opening and closing mechanism is arranged in the air duct, and the air inlet of the condensing furnace body is further provided with a baffle which is inclined into the condensing furnace body and extends upward.

[0011] Further, the bottom and the side of the baffle are sealed with the inner wall of the condensing furnace body, and the top end of the baffle leaves an opening with a smaller cross-sectional area than the air duct in the top wall of the condensing furnace body.

[0012] Further, the opening and closing mechanism is a double-door type rotating structure with two halves, and the opening and closing mechanism rotates to one side of the condensing furnace.

[0013] Further, the chromium plates in the condensing furnace body are staggered from top to bottom, and a plurality of through holes are arranged on the chromium plates in a spaced manner.

[0014] Further, at least two layers of condensing plates are staggered from top to bottom below the side heating structure in the condensing furnace body, and a condensing system is arranged on the outer wall of the condensing furnace body at the position of the condensing plates.

[0015] Further, the top end of each chromium plate in the condensing furnace body does not exceed the middle line of the furnace cavity of the condensing furnace body, and the top end of each condensing plate in the condensing furnace body exceeds the middle line of the furnace cavity of the condensing furnace body.

[0016] The method for preparing high-purity copper based on the vacuum distillation furnace comprises the steps of raw material heating, air duct control, vapor impurity removal and high-purity copper collection, and the specific contents are as follows:

[0017] A, raw material heating: copper raw material is added into the evaporation furnace through the feeding port, then the opening and closing mechanism is opened to connect the evaporation furnace and the condensing furnace, the vacuum system is controlled through the vacuum pipe to perform overall vacuumization, after completion, the heating unit is opened to heat the copper raw material, and the heating rate is controlled to melt the copper raw material;

[0018] B, airway control: during the process of melting and heating the copper raw material, the opening and closing mechanism is closed to isolate the evaporation furnace from the condensation furnace, then the vacuum system continues to control the vacuum degree of the condensation furnace until it stops, then the steam begins to generate in the evaporation furnace, and the opening width of the opening and closing mechanism is adjusted according to the needs, so that the steam in the evaporation furnace flows into the condensation furnace;

[0019] C, steam impurity removal: the steam enters the condensation furnace and sinks with the decrease of temperature, the steam contacts the chromium plate during the sinking process, the impurity elements in the steam chemically react with the chromium at high temperature and condense on the upper surface of the chromium plate, the steam that continues to sink is heated and warmed again when reaching the side heating structure, part of the steam evaporates upward and condenses on the lower surface of the chromium plate;

[0020] D, high-purity copper collection: after the time of chemical reaction and secondary heating of the steam in the condensation furnace reaches the preset length, the side heating structure is closed, the steam continues to cool and sink and most of the steam condenses on the condensation plate to obtain high-purity copper powder, and the remaining gas condenses on the condensation collection plate to obtain high-purity copper particles.

[0021] Further, the copper raw material is electrolytic cathode copper, copper-rich alloy, copper-rich secondary resources and / or recycled copper, the vacuum degree in the evaporation furnace and / or the condensation furnace is 0.1-100 Pa, the vacuum distillation temperature in the evaporation furnace is 1100-1800℃, the vacuum distillation time is 0.5-3h, and the vacuum distillation warming rate is 5-20℃ / min.

[0022] Further, in the steam impurity removal step, after the time of the steam entering the condensation furnace reaches the preset length, the opening and closing mechanism is closed to make the steam in the condensation furnace independently complete the impurity removal and condensation until the preset length is reached; or the opening and closing mechanism is continuously opened to make the steam generated in the evaporation furnace continuously enter the condensation furnace and remove the impurities and collect the high-purity copper.

[0023] The beneficial effects of the present application are:

[0024] 1, the present application can make the high-temperature steam generated in the evaporation furnace flow naturally into the condensation furnace according to the gravity by connecting the gas outlet at the top of the evaporation furnace with the gas inlet above the top layer of chromium plate in the condensation furnace, which can not only avoid the high-temperature steam gathering at the top end of the evaporation furnace, but also reduce or even eliminate the heating guide structure for steam flow, thereby reducing the energy consumption and simplifying the structure; and the top of the evaporation furnace and the condensation furnace is connected by the gas channel, so that the temperature gradient required for steam separation, reaction and condensation can be formed. At the same time, the steam pressure can be controlled by the vacuum system at the upper part of the condensation furnace to form a pressure gradient, combined with the heating unit of the evaporation furnace and the side heating structure of the condensation furnace, so that the temperature gradient and pressure gradient controllable system is formed, which can control the reaction path of the steam flow together, thereby effectively improving the efficiency of rectification and the purity of rectification products.

[0025] 2、The application according to the difference between the melting point of copper 1083℃ and the melting point of chromium 1907℃, and utilizing the characteristics that the impurity elements Al, Cd, Bi, Ga, K, Mg, Zn, Pb, Ga, Fe, Ni, Si, Au, Cl, etc. in high-temperature steam can chemically react with chromium in the volatilization process (according to the relationship of saturated vapor pressure, most of the above impurity elements are in a gaseous state and have a large activation energy in the given distillation temperature range, and will chemically react with chromium at high temperature), by setting a multi-layer chromium plate structure in the condensing furnace, the high-temperature steam can smoothly pass through, the multi-layer structure can increase the contact area and improve the temperature gradient, so that the impurity elements react with the chromium plate multiple times and condense on the upper surface of the chromium plate, realizing the separation of impurity elements and copper; at the same time, a side heating structure is arranged below the bottom layer of chromium plate, which can increase the steam temperature of the lower layer of chromium plate and enhance the reaction ability of the impurity elements, avoid the impurity elements from being brought into the final distillation product due to insufficient reaction caused by too low temperature, and when the steam in the condensing furnace drops to the side heating structure as the temperature decreases, the side heating structure heats the steam to the required temperature, part of the steam evaporates upward and part of the steam condenses on the lower surface of the chromium plate, further improving the separation effect.

[0026] 3、The application sets an upwardly inclined baffle in the gas inlet of the condensing furnace body, so that the baffle and the top of the condensing furnace body form a converging vent passage to form a Laval nozzle effect, the gas flowing through the baffle is thus compressed and heated due to the decrease in volume and increase in pressure, so that the volatilized substances are condensed and separated when passing through the converging vent passage, and the high-boiling-point substances are guided by the inclined baffle to return to the evaporation furnace, so that the separation effect of the volatilized substances collected in the condensing furnace and the residues of the evaporation furnace is better, and the baffle structure can control the rectification time and reflux speed by controlling the opening size and length of the air passage.

[0027] 4、The application sets the opening and closing mechanism which can rotate left and right in the air channel: when the opening and closing mechanism is closed, the evaporation furnace and the condensation furnace become two independent operation spaces, so that the evaporation temperature gradient and the pressure gradient can be stably controlled, and the evaporation furnace feeding can be realized without affecting the vacuum degree of the condensation furnace to realize continuous high-temperature distillation; when the opening and closing mechanism is opened, the evaporation furnace and the condensation furnace are communicated to form a steam passage. When the opening and closing mechanism is completely opened, it is a common parallel gas flow passage, and when the left and right are opened by one quarter, that is, the middle opening air channel is half, a narrow throat structure with large front and back openings and a contraction in the middle can also be formed; the evaporation furnace of the application exists due to the high-temperature steam, and forms a gas pressure difference with the condensation furnace, the steam flows from the evaporation furnace to the condensation furnace through the air channel, the steam is compressed to form high-speed compressed gas at the narrow throat, and after passing through the narrow throat, the steam rapidly expands to form a higher flow rate of gas, thereby forming a Laval nozzle effect, realizing rapid cooling of the volatile matter in the condensation furnace, and increasing the pressure difference of the evaporation furnace at the narrow throat of the air channel, so that the steam outflow speed is accelerated; at the same time, due to the left and right opening and closing structure, the narrow throat on both sides is a slope structure, the gas is compressed and heated at the narrow throat to reach the maximum pressure, thereby facilitating the condensation and separation of high-boiling-point substances and returning to the evaporation furnace, while the low-boiling-point substances quickly pass through the narrow throat to flow to the condensation furnace to achieve the effect of separation, and finally form a dynamic and efficient rectification effect. And the opening and closing mechanism increases the pressure difference between the evaporation furnace and the condensation furnace, so that the high-boiling-point substances in the evaporation furnace are not easy to volatilize, and the low-boiling-point substances quickly pass through the air channel and are rapidly condensed in the condensation furnace, thereby realizing more accurate and effective separation of alloy materials with smaller boiling point difference.

[0028] 5、The application sets the opening and closing mechanism and the baffle in the air channel at the same time, and when the opening and closing mechanism is opened by one quarter up and down, the double-stage Laval nozzle effect can be formed with the baffle structure, further improving the dynamic and efficient rectification effect.

[0029] 6、The application sets the condensation plate, the condensation collection plate in sequence below the side heating structure of the condensation furnace, and further sets the condensation system on the side wall of the condensation furnace at the position of the condensation plate, so that the temperature of the high-temperature steam is rapidly reduced after the reaction with the chromium plate, thereby making the copper steam rapidly condensed into copper powder particles and most of the condensed copper powder particles are condensed on the condensation plate, and the remaining copper powder particles are condensed on the condensation collection plate to obtain high-purity copper powder and particles, which not only improves the condensation efficiency, but also reduces the mutual fusion of copper melt particles in the steam, effectively reducing the particle size of the copper powder.

[0030] In summary, the application has the characteristics of compact structure, low energy consumption, high rectification efficiency, good impurity removal effect, and high purity of rectification products. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The figure is a schematic diagram of the vacuum distillation furnace structure of the application;

[0032] Figure 2 A-A sectional view of Figure 1

[0033] Figure 3 B-B sectional view of Figure 1

[0034] Figure 4 Connection diagram of the evaporation furnace and the condensation furnace of the present application;

[0035] Figure 5 Connection diagram of the evaporation furnace and the condensation furnace of the present application;

[0036] In the figure: 1-evaporation furnace, 11-evaporation furnace body, 12-charging port, 13-discharge port, 14-top cover, 15-charging port end cover, 16-discharge port end cover, 2-condensation furnace, 21-condensation furnace body, 22-vacuum pipe, 23-chromium plate, 24-side heating structure, 25-condensation plate, 26-condensation collection plate, 27-condensation system, 3-air duct, 31-opening and closing mechanism, 32-shutter, 33-opening, 4-furnace shell, 5-refractory brick. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0038] As shown in Figure 1 , 2 and 3, the vacuum distillation furnace of the present application comprises an evaporation furnace 1, a condensation furnace 2 and an air duct 3. The evaporation furnace 1 comprises an evaporation furnace body 11. The upper part and the bottom of the evaporation furnace body 11 are respectively provided with a charging port 12 and a discharge port 13 which can communicate with the inside and outside. The side, upper part and / or bottom of the evaporation furnace body 11 is provided with a heating unit. The top end of the evaporation furnace body 11 is detachably provided with a top cover 14.

[0039] The condensation furnace 2 comprises a condensation furnace body 21. The top end of the condensation furnace body 21 is provided with a vacuum pipe 22 which communicates with a vacuum system. The upper part and / or middle part of the condensation furnace body 21 is provided with a plurality of transverse chromium plates 23 which are spaced apart from top to bottom. The condensation furnace body 21 is sequentially and spaced apart provided below the bottom chromium plate 23 with a side heating structure 24, a condensation plate 25 and a condensation collection plate 26.

[0040] The top of the evaporation furnace body 11 is provided with an air outlet. The top of the condensation furnace body 21 is provided with an air inlet above the top chromium plate 23. The air duct 3 communicates the air outlet of the evaporation furnace 1 with the air inlet of the condensation furnace 2.

[0041] ​​The air passage 3 is also provided with an open-close mechanism 31 which can be controlled to open and close, and the air inlet of the condensing furnace body 21 is also provided with a baffle 32 which is inclined and extends upwardly into the condensing furnace body 21.

[0042] The bottom and side of the baffle 32 are sealed with the inner wall of the condensing furnace body 21, and the top end of the baffle 32 is left with an opening 33 which has a smaller cross-sectional area than the air passage 3.

[0043] The open-close mechanism 31 is a double-door type rotating structure with two halves, and the open-close mechanism 31 rotates to open and close to one side of the condensing furnace 2.

[0044] The chromium plates 23 in the condensing furnace body 21 are staggered from top to bottom, and a plurality of through holes are arranged at intervals on the chromium plates 23.

[0045] At least two layers of condensing plates 25 are staggered from top to bottom below the side heating structure 24 in the condensing furnace body 21, and the condensing system 27 is arranged on the outer wall of the condensing furnace body 21 at the position of the condensing plates 25.

[0046] The lower part of the condensing furnace body 21 is provided with a condensing cavity which has a larger transverse dimension than the middle and upper parts of the condensing furnace body 21, the side heating structure 24 is arranged at the top end of the condensing cavity, the condensing plates 25 are arranged in the cooling cavity, the condensing system 27 is arranged on the side wall of the condensing cavity, and the condensing collection plate 26 is arranged at the bottom end of the cooling cavity.

[0047] The top end of each chromium plate 23 in the condensing furnace body 21 does not exceed the center line of the furnace cavity of the condensing furnace body 21, and the top end of each condensing plate 25 in the condensing furnace body 21 exceeds the center line of the furnace cavity of the condensing furnace body 21.

[0048] The heating unit is an electromagnetic induction heating body or a resistance wire arranged on the side of the evaporation furnace body 11.

[0049] As shown in Figure 4 and 5 The condensing furnace 2 is connected with one or more evaporation furnaces 1 through the air passage 3.

[0050] As shown in Figure 1 , 2 and 3, the method for preparing high-purity copper based on a vacuum distillation furnace of the present application comprises the steps of raw material heating, air passage control, vapor impurity removal, and high-purity copper collection, and the specific contents are as follows:

[0051] A. Raw material heating: copper raw material is added to the evaporation furnace 1 through the feeding opening 12, then the open-close mechanism 31 is opened to connect the evaporation furnace 1 with the condensing furnace 2, and the vacuum system is controlled through the vacuum pipe 22 to perform overall vacuumization, after completion, the heating unit is turned on to heat the copper raw material, and the heating rate is controlled to melt the copper raw material;

[0052] B. Airway control: during the melting and heating process of the copper raw material, the opening and closing mechanism 31 is closed to isolate the evaporation furnace 1 from the condensation furnace 2, then the vacuum system continues to control the vacuum degree of the condensation furnace 2 until it stops, and then the steam begins to generate in the evaporation furnace 1, the opening width of the opening and closing mechanism 31 is adjusted according to the need, so that the steam in the evaporation furnace 1 flows into the condensation furnace 2;

[0053] C. Steam impurity removal: the steam enters the condensation furnace 2 and sinks with the decrease of temperature, the steam contacts the chromium plate 23 during the sinking process, the impurity elements in the steam chemically react with chromium at high temperature and condense on the upper surface of the chromium plate 23, the steam that continues to sink is heated and warmed up when reaching the side heating structure 24, part of the steam evaporates upward and condenses on the lower surface of the chromium plate 23;

[0054] D. High-purity copper collection: after the time of the steam chemical reaction and secondary heating in the condensation furnace 2 reaches the preset time length, the side heating structure 24 is closed, the steam continues to cool and sink and most of it condenses on the condensation plate 25 to obtain high-purity copper powder, and the remaining gas condenses on the condensation collection plate 26 to obtain high-purity copper particles.

[0055] The copper raw material is electrolytic cathode copper, copper-rich alloy, copper-rich secondary resources and / or recycled copper, the vacuum degree in the evaporation furnace 1 and / or the condensation furnace 2 is 0.1-100 Pa, the vacuum distillation temperature in the evaporation furnace 1 is 1100-1800℃, the vacuum distillation time is 0.5-3h and the vacuum distillation heating rate is 5-20℃ / min.

[0056] In the airway control, steam impurity removal and high-purity copper collection steps, the vacuum degree value in the condensation furnace 2 is smaller than that in the evaporation furnace 1; preferably, the vacuum degree in the condensation furnace 2 is 0.1-60 Pa and the vacuum degree in the evaporation furnace 1 is 10-100 Pa.

[0057] In the steam impurity removal step, after the time of the steam entering the condensation furnace 2 reaches the preset time length, the opening and closing mechanism 31 is closed to make the steam in the condensation furnace 2 independently complete the impurity removal and condensation until the preset time length is reached; or the opening and closing mechanism 31 is continuously opened to make the steam generated in the evaporation furnace 1 continuously enter the condensation furnace 2 and remove the impurities and collect the high-purity copper.

[0058] In the high-purity copper collection step, the side heating structure 24 is closed at the same time the condensation system 27 on the side wall is opened.

[0059] The particle size of the high-purity copper particles is 1-100μm.

[0060] Example 1

[0061] As Figure 1 , 2As shown in Figs. 1-3, the electrolytic cathode copper is vacuum distilled to prepare high-purity copper particles by using the vacuum distillation furnace of the present application, and the specific process is as follows:

[0062] S100: The electrolytic cathode copper is added into the evaporation furnace 1 through the feeding port 12, then the opening and closing mechanism 31 is opened to connect the evaporation furnace 1 and the condensation furnace 2, and the whole is vacuumized to 50 Pa by controlling the vacuum system through the vacuum pipe 22, after completion, the heating unit is opened to heat the electrolytic cathode copper, and the temperature rising rate is controlled at 5-20 ℃ / min, and the temperature is raised to 1100-1800 ℃ to melt the electrolytic cathode copper.

[0063] S200: During the melting and heating process of the electrolytic cathode copper in the evaporation furnace 1, the opening and closing mechanism 31 in the gas channel 3 is closed to isolate the evaporation furnace 1 and the condensation furnace 2, then the vacuum system is continuously controlled to vacuumize the condensation furnace 2 to 10 Pa and then stop, and then after the evaporation starts in the evaporation furnace 1, the opening and closing mechanism 31 is adjusted in width according to the need to make the steam in the evaporation furnace 1 flow into the condensation furnace 2. The opening and closing mechanism 31 and the top of the evaporation furnace 1 form a converging nozzle-shaped air passage, which can form a Laval nozzle effect, the volume of the steam flowing here is reduced and the pressure is increased, and this structure makes the volatile matter pass through the gas channel 3, the gas reaches the maximum pressure at the narrow throat and is compressed and heated, the high-boiling-point substances are condensed and separated and flow back to the evaporation furnace 1, so that the separation effect of the volatile matter collected in the condensation chamber and the residues in the evaporation chamber is better. Then the gas enters the condensation furnace 2, and the opening and closing mechanism 31 can be closed after a period of time to achieve optimal control of the gas. The opening and closing mechanism 31 can also be opened to enable continuous processing of high-temperature steam.

[0064] S300: The steam flows into the condensation furnace 2 and sinks with the decrease of temperature, the Fe, Si, Mn, Al, Cl, Si, S, O, N and C impurity elements in the steam chemically react with chromium at high temperature and condense on the upper surface of the chromium plate 23, and the steam that continues to sink is heated and raised in temperature when reaching the side heating structure 24, part of the steam evaporates upward and part condenses on the lower surface of the chromium plate 23.

[0065] S400: After the time of chemical reaction and secondary heating of the steam in the condensation furnace 2 reaches the preset length, the side heating structure 24 is closed, and at the same time the condensation system 27 on the side wall of the condensation furnace 2 is opened, so that the steam quickly cools and sinks and most of it condenses on the condensation plate 25 to obtain high-purity copper powder, and the remaining steam condenses on the condensation collection plate 26 to obtain high-purity copper particles.

[0066] The above merely provides the preferred but not limiting embodiments of the present application, and any modification or substitution within the technical scope of the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A vacuum distillation furnace, comprising an evaporator (1), a condenser (2), and a gas duct (3), wherein the evaporator (1) comprises an evaporator body (11), wherein the upper part and the bottom of the evaporator body (11) are respectively provided with a feeding port (12) and a slag discharge port (13) that can communicate with the inside and outside, wherein the side, upper part and / or bottom of the evaporator body (11) are provided with a heating unit, and the top of the evaporator body (11) is detachably provided with a top cover (14). Its features The condensing furnace (2) includes a condensing furnace body (21). The top of the condensing furnace body (21) is provided with a vacuum tube (22) connected to a vacuum system. The upper part and / or middle part of the condensing furnace body (21) is provided with a number of horizontal chromium plates (23) spaced from top to bottom. The condensing furnace body (21) is provided with a side heating structure (24), a condensing plate (25) and a condensation collection plate (26) spaced from bottom to bottom below the bottom chromium plate (23). The top of the evaporator body (11) is provided with an air outlet, and the top of the condenser body (21) is provided with an air inlet above the top chromium plate (23). The air passage (3) connects the air outlet of the evaporator (1) and the air inlet of the condenser (2). The air passage (3) is also provided with an opening and closing mechanism (31) that can be controlled to open and close, and the air inlet of the condensing furnace body (21) is also provided with a baffle (32) that is inclined into the condensing furnace body (21) and extends upward. The bottom and sides of the baffle (32) are sealed to the inner wall of the condenser body (21), and an opening (33) with a cross-sectional area smaller than that of the gas passage (3) is left between the top of the baffle (32) and the top wall of the condenser body (21). The opening and closing mechanism (31) is a double-door rotating structure with two halves on the left and right sides. The opening and closing mechanism (31) rotates and opens and closes towards the condensing furnace (2) side. The chromium plates (23) inside the condensing furnace body (21) are arranged alternately from top to bottom, and the chromium plates (23) are provided with several through holes at intervals; The top of each chromium plate (23) in the condensing furnace body (21) does not exceed the center line of the furnace cavity of the condensing furnace body (21), and the top of each condensing plate (25) in the condensing furnace body (21) exceeds the center line of the furnace cavity of the condensing furnace body (21).

2. The vacuum distillation furnace according to claim 1, characterized in that... The condensing furnace body (21) has at least two layers of condensing plates (25) arranged alternately from top to bottom below the internal side heating structure (24), and the condensing furnace body (21) has a condensing system (27) on the outer wall where the condensing plates (25) are located.

3. A method for preparing high-purity copper using the vacuum distillation furnace described in claim 1 or 2, characterized in that... The process includes raw material heating, gas duct control, steam purification, and high-purity copper collection. The specific steps are as follows: A. Raw material heating: Copper raw material is added to evaporator (1) through feeding port (12), and then the opening and closing mechanism (31) is opened to connect evaporator (1) and condenser (2), and the vacuum system is controlled by vacuum tube (22) to perform overall vacuuming. After completion, the heating unit is opened to heat the copper raw material, and the heating rate is controlled to melt the copper raw material. B. Gas duct control: During the melting and heating process of copper raw materials, the opening and closing mechanism (31) is closed to isolate the evaporator (1) from the condenser (2). Then, the vacuum system is controlled to evacuate the condenser (2) to the preset vacuum level and then stops. After steam is generated in the evaporator (1), the opening width of the opening and closing mechanism (31) is adjusted as needed to allow the steam in the evaporator (1) to flow into the condenser (2). C. Steam impurity removal: Steam is introduced into the condenser (2) and sinks as the temperature decreases. During the sinking process, the steam comes into contact with the chromium plate (23). The impurity elements in the steam react with chromium at high temperature and condense on the upper surface of the chromium plate (23). The steam that continues to sink is heated again when it reaches the side heating structure (24). Some of the steam rises and condenses on the lower surface of the chromium plate (23). D. High-purity copper collection: After the steam undergoes chemical reaction and secondary heating in the condenser furnace (2) for a preset time, the side heating structure (24) is closed. The steam continues to cool down and sinks, and most of it is condensed on the condenser plate (25) to obtain high-purity copper powder. The remaining gas is condensed on the condenser collection plate (26) to obtain high-purity copper particles.

4. The method for preparing high-purity copper in a vacuum distillation furnace according to claim 3, characterized in that... The copper raw material is electrolytic cathode copper, copper-rich alloy, copper-rich secondary resources and / or recycled copper. The vacuum degree in the evaporation furnace (1) and / or condensation furnace (2) is 0.1 to 100 Pa. The vacuum distillation temperature in the evaporation furnace (1) is 1100 to 1800 °C, the vacuum distillation time is 0.5 to 3 h, and the vacuum distillation heating rate is 5 to 20 °C / min.

5. The method for preparing high-purity copper in a vacuum distillation furnace according to claim 3 or 4, characterized in that... In the steam purification step, after the steam is introduced into the condenser (2) for a preset time, the opening and closing mechanism (31) is closed so that the steam in the condenser (2) can independently complete the purification and condensation until the preset time is reached; or the opening and closing mechanism (31) is continuously opened so that the steam generated by the evaporator (1) can continuously enter the condenser (2) for purification and collection of high-purity copper.

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