Method for treating waste circuit boards and copper-containing sludge in a continuous copper smelting process

Abstract

The present invention provides a method for treating waste circuit boards and copper-containing sludge in a continuous copper smelting process. The method comprises step S1, smelting raw materials including copper-containing sludge, waste circuit boards, copper concentrate, and flux in oxygen-enriched air to obtain copper matte, smelting slag, and flue gas and dust; step S2, continuously blowing raw materials including copper matte, fuel, and slagging agent in an oxygen-containing atmosphere to obtain blister copper, blowing slag, and flue gas and dust; step S3, refining the blister copper in a rotary anode furnace to obtain anode copper, refining slag, and flue gas; and step S4, electrolyzing the anode copper to obtain copper cathode plates and anode mud. The above method is intended to simultaneously treat hazardous waste waste circuit boards and copper-containing sludge during the copper smelting process, achieving efficient and green comprehensive recovery of valuable metals such as copper, gold, and silver, thereby reducing storage and processing costs. Furthermore, the above method does not require complex pretreatment of the raw materials, which helps to further reduce costs.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous copper smelting, and in particular to a method for treating waste circuit boards and copper-containing sludge in a continuous copper smelting process. Background Art

[0002] Today's copper smelting technology is developing towards intensification, high efficiency, green environmental protection and comprehensive recycling. Continuous copper smelting processes are becoming diversified, and the technology for recycling precious metals such as gold and silver is mature and has a high recovery rate.

[0003] With the development of technology and social progress, a large number of electronic equipment have begun to be scrapped, and a large number of waste circuit boards are generated during the dismantling process. Since most waste circuit boards contain harmful elements such as lead and mercury, and the epoxy resins and flame retardants contained in their organic components will produce a large amount of carcinogenic harmful substances if they are not properly disposed of, waste circuit boards are classified as hazardous waste; but because they contain valuable metals such as copper, gold, silver, platinum, palladium, tin, nickel, and zinc, they have a high recycling value.

[0004] The sludge obtained after treating the wastewater generated during the electroplating process contains valuable metal elements such as copper, but the types and contents of sludge components produced by different processes vary greatly. Due to the production principle of copper-containing sludge and its own properties, it is listed as hazardous waste. If it is not properly disposed of, it is easy to cause pollution. However, the valuable metals it contains have high resource value.

[0005] Patent application number 202010757311.8 describes a method and apparatus for processing copper concentrate, waste circuit boards, and desulfurized gypsum in an Ausmelt furnace. This method involves disassembling the waste circuit boards to remove impurities such as iron, aluminum, and copper wire, then crushing them. The resulting waste circuit boards are then mixed with copper concentrate and desulfurized gypsum, granulated, and then smelted in an Ausmelt furnace. The desulfurized gypsum is added primarily to reduce the chlorides required for dioxin production by reacting its calcium with chlorides to form high-boiling calcium chloride. However, the disassembly process is lengthy, the equipment complex, and the investment required is high. The process is highly polluting and the processing cost is high. Summary of the Invention

[0006] The main purpose of the present invention is to provide a method for treating waste circuit boards and copper-containing sludge in a continuous copper smelting process, so as to solve the problems in the prior art of treating copper concentrate, waste circuit boards, etc., such as long disassembly process, complex equipment, large investment, serious pollution in the disassembly process and high treatment cost.

[0007] To achieve the above-mentioned object, according to one aspect of the present invention, a method for treating waste circuit boards and copper-containing sludge in a continuous copper smelting process is provided, the method comprising step S1, smelting raw materials including copper-containing sludge, waste circuit boards, copper concentrate, and flux in oxygen-enriched air to obtain copper matte, smelting slag, and flue gas and dust; step S2, continuously blowing raw materials including copper matte, fuel, and slagging agent in an oxygen-containing atmosphere to obtain blister copper, blowing slag, and flue gas and dust; step S3, refining the blister copper in a rotary anode furnace to obtain anode copper, refining slag, and flue gas; and step S4, electrolyzing the anode copper to obtain copper cathode plates and anode mud.

[0008] Furthermore, the above-mentioned step S1 also includes the step of pre-detinning and crushing the waste circuit boards, preferably the particle size of the crushed waste circuit boards is 10 to 50 mm, and preferably the tin content of the crushed waste circuit boards is 3 to 5%; preferably, step S1 also includes the step of pre-dehydrating the copper-containing sludge, and preferably the moisture content of the dehydrated copper-containing sludge is 10 to 15%.

[0009] Furthermore, the above method further comprises: subjecting the flue gas and dust in step S1 to boiler waste heat recovery treatment, dust collection, and flue gas acidification treatment in sequence to obtain exhaust flue gas, wherein the dioxin content of the flue gas and dust is preferably 0.032-0.05 ng TEQ / m 3 The dioxin content in the exhaust gas is preferably 0.008 to 0.012 ng TEQ / m 3 .

[0010] Furthermore, in the above step S1, the feed ratio of copper-containing sludge, waste circuit boards, and copper concentrate is 2-6:4-10:50-100 on a dry basis of copper-containing sludge, and the raw materials preferably further include cold material, which is 5-8wt% of the copper concentrate, and the cold material is preferably selected from any one or more of blowing slag, slag concentrate, and refined slag; the volume content of oxygen in the oxygen-enriched air is preferably 60-90%; the flux is preferably 10-15wt% of the copper concentrate, and the flux is preferably selected from any one or more of quartz stone, quicklime, dolomite, and quartz sand, and the flux is preferably quartz stone; the smelting is preferably selected from any one of bottom blowing smelting, side blowing smelting, and top blowing smelting, and the smelting is preferably carried out in a smelting furnace.

[0011] Furthermore, in the above step S1, the copper grade in the copper matte is 65-75%, the gold and silver capture rates are above 98%, and the platinum and palladium capture rates are above 99%.

[0012] Furthermore, in the above step S2, the volume content of oxygen in the oxygen-containing atmosphere is 24-34%; the fuel is preferably lump coal, the lump coal rate is preferably 0.5-1%, and the particle size of the lump coal is preferably 5-15 mm.

[0013] Furthermore, the above method also includes: subjecting the flue gas and dust in step S2 to boiler waste heat recovery treatment, dust collection, and flue gas acidification treatment in sequence to obtain exhaust flue gas, preferably returning the blowing slag to step S1 as part of the cold material, and / or returning the blowing slag to step S2 as part of the cold material; preferably, the continuous blowing is bottom blowing or multi-lance top blowing, and preferably, the continuous blowing is carried out in a blowing furnace.

[0014] Furthermore, in the above step S2, when the continuous blowing is bottom blowing, the slag-forming agent is ferrosilicon slag, and preferably the Fe / SiO2 in the ferrosilicon slag is 0.8 to 1.2:1; when the continuous blowing is multi-gun top blowing, the slag-forming agent is ferrocalcium slag, and preferably the Fe / CaO in the ferrocalcium slag is 2.3 to 2.5:1; the copper content of the blister copper is preferably greater than 98.5%, and when the smelting is bottom blowing, the total recovery rate of gold reaches more than 98%, and the total recovery rate of silver reaches more than 97%; when the smelting is side blowing, the total recovery rate of gold reaches more than 97%, and the total recovery rate of silver reaches more than 96%.

[0015] Furthermore, in the above step S3, the spent anodes, fuel and oxygen-enriched air are refined in a rotary anode furnace, preferably the spent anodes are cast waste plates and / or residual anodes, and the fuel is preferably selected from any one or more of natural gas, diesel and pulverized coal; the volume content of oxygen in the oxygen-enriched air is preferably 60-90%; the refined slag is preferably returned to step S1 as part of the cold material, and / or the refined slag is returned to step S2 as part of the cold material.

[0016] Furthermore, the total recovery rate of the copper is greater than 98%.

[0017] Applying the technical solution of the present application, the above method of the present application is intended to simultaneously treat hazardous waste waste circuit boards and copper-containing sludge during the copper smelting process, achieving efficient and green comprehensive recovery of valuable metals such as copper, gold, and silver, while reducing storage and processing costs. Specifically, by leveraging the high temperature conditions and oxygen-rich air generated by the excess heat in the copper smelting process, elemental sulfur produced by the decomposition of copper concentrate is fully utilized as a reducing agent. This reducing agent reduces copper and other valuable metal oxides in the copper-containing sludge to copper matte. The high temperature conditions of the copper smelting process are utilized to promote the combustion of organic matter in the waste circuit boards, reducing the difficulty and cost of waste circuit board disposal. Heat is also generated, thereby avoiding the need for large amounts of carbonaceous reducing agents or fuels required for separate treatment of the copper-containing sludge. Calcium in the copper-containing sludge is also utilized as a solidifying agent to solidify the chlorine in the waste circuit boards, suppressing the chlorides required for dioxin production during the flue gas cooling process, producing harmless flue gas, and effectively improving the environment. At the same time, the high temperature conditions of the copper smelting process are utilized to treat the copper-containing sludge, recovering the valuable metals while smelting other substances into pyrometallurgical slag, which becomes general solid waste. The resulting harmless tailings can be used as an additive in cement plants. As can be seen, the above method can successfully achieve the goal of large-scale, harmless, and low-cost disposal of hazardous waste, while also recovering valuable metal elements. This makes the method of treating waste circuit boards in conjunction with continuous copper smelting a green, environmentally friendly, safe, reliable, and economically efficient process. Furthermore, the above method does not require complex pretreatment of the raw materials, avoiding the problems of prior art wet treatment methods that produce waste acid and waste residue, and the need for additional fuel such as coal due to low oxygen concentration. Furthermore, it helps fully utilize the continuous copper smelting equipment and treat the aforementioned hazardous waste at a low equipment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 A schematic diagram of a treatment process flow for treating waste circuit boards and copper-containing sludge in a continuous copper smelting process according to Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] As analyzed in the background technology of this application, the existing technology for the combined treatment of copper concentrate, waste circuit boards, etc. has the problems of long disassembly process, complex equipment, large investment, serious pollution in the disassembly process and high treatment cost. In order to solve this problem, this application provides a method for the combined treatment of waste circuit boards and copper-containing sludge in a continuous copper smelting process.

[0022] In one embodiment of the present application, a method for treating waste circuit boards and copper-containing sludge in a continuous copper smelting process is provided, the method comprising: step S1, smelting raw materials including copper-containing sludge, waste circuit boards, copper concentrate, and flux in oxygen-enriched air to obtain copper matte, smelting slag, and flue gas and dust; step S2, continuously blowing raw materials including copper matte, fuel, and slagging agent in an oxygen-containing atmosphere to obtain blister copper, blowing slag, and flue gas and dust; step S3, refining the blister copper in a rotary anode furnace to obtain anode copper, refined slag, and flue gas; and step S4, electrolyzing the anode copper to obtain copper cathode plates and anode mud.

[0023] The above method of the present application is intended to simultaneously treat hazardous waste waste circuit boards and copper-containing sludge during the copper smelting process, achieving efficient and green comprehensive recovery of valuable metals such as copper, gold, and silver, and reducing storage and processing costs. Specifically, with the help of the high temperature conditions and oxygen-rich air generated by the excess heat in the copper smelting process, the elemental sulfur produced by the decomposition of copper concentrate is fully utilized as a reducing agent. The reducing agent reduces copper and other valuable metal oxides in the copper-containing sludge to copper matte. The high temperature conditions of the copper smelting process are used to promote the combustion of organic matter in the waste circuit boards, reducing the difficulty and cost of disposing of the waste circuit boards. At the same time, heat is generated, thereby avoiding the need for a large amount of carbonaceous reducing agent or fuel to treat the copper-containing sludge alone; and the calcium in the copper-containing sludge is used as a curing agent to solidify the chlorine in the waste circuit boards, inhibiting the chloride required for dioxin production during the flue gas cooling process, producing harmless flue gas, and effectively improving the environment. At the same time, the high temperature conditions of the copper smelting process are used to treat the copper-containing sludge, while recovering the valuable metals therein, and smelting other substances into pyrometallurgical slag to become general solid waste. The harmless tailings produced are used in cement plants as additives. As can be seen, the above method can successfully achieve the goal of large-scale, harmless, and low-cost disposal of hazardous waste, while also recovering valuable metal elements. This makes the method of treating waste circuit boards in conjunction with continuous copper smelting a green, environmentally friendly, safe, reliable, and economically efficient process. Furthermore, the above method does not require complex pretreatment of the raw materials, avoiding the problems of prior art wet treatment methods that produce waste acid and waste residue, and the need for additional fuel such as coal due to low oxygen concentration. Furthermore, it helps fully utilize the continuous copper smelting equipment and treat the aforementioned hazardous waste at a low equipment cost.

[0024] In one embodiment of the present application, the above-mentioned step S1 also includes the step of pre-detinning and crushing the waste circuit boards, preferably, the particle size of the waste circuit boards after crushing is 10 to 50 mm, and preferably, the tin content of the waste circuit boards after crushing is 3 to 5%; preferably, step S1 also includes the step of pre-dehydrating the copper-containing sludge, and preferably, the moisture content of the copper-containing sludge after dehydration is 10 to 15%.

[0025] The raw materials fed into the furnace in step S1 are fed into the smelting furnace through the top charging port of the smelting furnace by a belt conveyor according to the results of metallurgical calculations for smelting. Copper, nickel, gold, silver, platinum, palladium, etc. are enriched and recycled in the copper matte layer, organic matter is burned at high temperature, and other impurities participate in slag formation. Calcium in the copper-containing sludge enters the slag to fix chlorine in the waste circuit boards (copper-containing sludge also contains calcium oxides, and the calcium content in copper-containing sludge is generally 5-20wt%), thereby reducing the chlorine required for dioxin generation during the flue gas cooling process (on the one hand, common chlorides such as ferrosilicon have low boiling points and are easily volatile, resulting in a large amount of chloride required for dioxin generation during the flue gas cooling process). The present application makes full use of the calcium in the copper-containing sludge as a solidifying agent for the chlorine in the waste circuit boards to form calcium chloride with a boiling point of 1600°C (much higher than the boiling point of other chlorides), which is much higher than the copper smelting temperature (1150-1300°C). The chlorine is solidified in the slag, thereby avoiding or reducing the production of dioxins due to the presence of chlorides during the flue gas cooling process; the sulfur decomposed from the organic matter of the waste circuit boards and the copper concentrate is used to reduce the copper-nickel oxides in the copper-containing sludge, avoiding the need for a separate reducing agent for the treatment of the copper-containing sludge; the combustion of the organic matter of the waste circuit boards and the heat released by the smelting of the copper concentrate provide heat for the treatment of the copper-containing sludge, avoiding the need for a large amount of fuel for the disposal of the copper-containing sludge.

[0026] Crushing waste circuit boards to obtain the above particle size range is more conducive to increasing their contact area with other raw materials during the smelting process, thereby maximizing the separation of valuable metals from other impurities and recovering the valuable metals. Dehydrating copper-containing sludge to obtain copper-containing sludge with the above moisture content helps reduce the heat consumed by the water and improve smelting efficiency. 5-20 wt% of calcium in the copper-containing sludge is preferably used as a solidifying agent to fix the chlorine in the waste circuit boards, thereby significantly reducing the chlorine required to generate dioxins during flue gas cooling and, in turn, reducing the dioxin content in the flue gas dust. Waste circuit boards contain a relatively high tin content, and pretreatment of the waste circuit boards helps reduce their tin content. The metallic tin primarily volatilizes into the flue gas during smelting and continuous blowing. During the flue gas dust removal process, most of the metallic tin enters the white dust collected by the electrostatic precipitator for recovery.

[0027] In one embodiment of the present application, the method further comprises: subjecting the flue gas and dust in step S1 to boiler waste heat recovery treatment, dust collection, and flue gas acidification treatment in sequence to obtain exhaust flue gas, preferably with a dioxin content of 0.032 to 0.05 ng TEQ / m 3 The dioxin content in the exhaust gas is preferably 0.008 to 0.012 ng TEQ / m 3 .

[0028] The preferred method described above helps reduce the dioxin content in flue gas dust to within the aforementioned range, thereby significantly reducing the dioxin content in the flue gas dust from the source. By sequentially subjecting the flue gas dust to boiler waste heat recovery, dust collection, and flue gas acidification, not only can the heat be recovered but the dioxin content can also be further reduced, thereby ensuring that the exhaust flue gas meets emission standards and minimizing its environmental pollution. The preferred method of returning the smelting slag to step S1 as a portion of the cold material helps reduce waste slag storage, while also helping to improve waste resource utilization and reduce costs.

[0029] In one embodiment of the present application, in the above step S1, the feed ratio of copper-containing sludge, waste circuit boards, and copper concentrate is 2-6:4-10:50-100, calculated on a dry basis of copper-containing sludge. Preferably, the raw materials also include cold material, which is 5-8wt% of the copper concentrate. Preferably, the cold material is selected from any one or more of blowing slag, slag concentrate, and refined slag; preferably, the volume content of oxygen in the oxygen-enriched air is 60-90%; preferably, the flux is 10-15wt% of the copper concentrate, preferably, the flux is selected from any one or more of quartz stone, quicklime, dolomite, and quartz sand, and preferably, the flux is quartz stone; preferably, the smelting is selected from any one of bottom blowing smelting, side blowing smelting, and top blowing smelting, and preferably, the smelting is carried out in a smelting furnace.

[0030] The feed ratio of copper-containing sludge, scrap printed circuit boards, and copper concentrate facilitates more effective synergy among the three, addressing the following aspects: Leveraging the high temperature of copper concentrate, the system disposes of organic matter in scrap printed circuit boards while providing fuel for the entire process. The elemental sulfur produced by the decomposition of copper concentrate reduces copper and other valuable metal oxides in the copper-containing sludge. The type and amount of cold material help regulate and maintain the temperature of the smelting system. The type and amount of flux improve the fluidity of the melt and promote the separation of copper matte from smelting slag. By utilizing air leakage or adding secondary combustion air / oxygen-enriched air to the upper portion of the smelting furnace, the organic matter in the scrap printed circuit boards is fully burned at high temperatures in the upper portion of the molten pool, thereby reducing the production of dioxins.

[0031] Through the above preparation method of the present application, copper, nickel, gold, silver, platinum, palladium, etc. enter the copper matte, and the copper grade in the copper matte in the above step S1 is 65-75%, the gold and silver capture rate reaches more than 98%, and the platinum and palladium capture rate reaches more than 99%.

[0032] In one embodiment of the present application, in the above step S2, the volume content of oxygen in the oxygen-containing atmosphere is 24-34%; the preferred fuel is lump coal, the preferred lump coal rate is 0.5-1%, and the preferred lump coal particle size is 5-15 mm.

[0033] The preferred oxygen content in the oxygen-containing atmosphere, the particle size of the lump coal and the lump coal rate are beneficial to increasing the contact area between the two and providing sufficient heat for the system.

[0034] In some preferred embodiments of the present application, the method further comprises: sequentially subjecting the flue gas and dust from step S2 to boiler waste heat recovery, dust collection, and flue gas acidification to produce exhaust flue gas; preferably, returning the blowing slag to step S1 as part of the cold material; and / or returning the blowing slag to step S2 as part of the cold material, thereby reducing waste slag storage, improving waste resource utilization, and reducing costs. Preferably, in step S2, the continuous blowing is bottom blowing or multi-lance top blowing, preferably performed in a blowing furnace, thereby more easily refining the valuable metals in the copper matte.

[0035] In one embodiment of the present application, in the above step S2, when the continuous blowing is bottom blowing, the slag-forming agent is ferrosilicon slag, and preferably the Fe / SiO2 in the ferrosilicon slag is 0.8-1.2:1; preferably, when the continuous blowing is multi-gun top blowing, the slag-forming agent is ferrocalcium slag, and preferably the Fe / CaO in the ferrocalcium slag is 2.3-2.5:1; preferably, the copper content of the blister copper is greater than 98.5%, and preferably, when the smelting is bottom blowing, the total recovery rate of gold reaches more than 98%, and the total recovery rate of silver reaches more than 97%; preferably, when the smelting is side blowing, the total recovery rate of gold reaches more than 97%, and the total recovery rate of silver reaches more than 96%.

[0036] Copper matte is discharged intermittently or continuously through a chute into a continuous converting furnace. Continuous converting produces blister copper containing nickel, gold, silver, platinum, and palladium. Different slag types are selected according to different processes. The preferred slag-forming agent type corresponding to the above continuous converting helps to minimize impurities in the blister copper and promotes efficient separation of the blister copper and converting slag. The preferred smelting methods described above all achieve high gold and silver recovery rates, thereby fully recovering valuable metals such as gold and silver from scrap circuit boards. The calcium-to-iron ratio of the iron-calcium slag used helps separate the valuable metals from the copper matte under sufficient heat. Furthermore, the preferred calcium-to-iron ratio for slagging is 2.3:1, 2.4:1, or 2.5:1.

[0037] In one embodiment of the present application, in the above-mentioned step S3, the waste anode, fuel and oxygen-enriched air are refined in a rotary anode furnace, preferably the waste anode is a casting waste plate and / or a residual anode, and the fuel is preferably selected from any one or more of natural gas, diesel and pulverized coal; the refined slag is preferably returned to step S1 as part of the cold material, and / or the refined slag is returned to step S2 as part of the cold material.

[0038] The above rotary anode furnace refining allows copper and valuable metals such as gold, silver, platinum and palladium to be further enriched.

[0039] The environmentally friendly flue gas generated during the above continuous discharge and transportation process of copper matte and copper crude is discharged after being treated to meet the standards.

[0040] The crude copper siphoned from the converting furnace and discharged from the copper port flows alternately and continuously through chutes into two rotary anode furnaces for fire refining. Two anode furnaces are set up for alternating operation. After entering the anode furnace, the crude copper is first oxidized and then reduced to produce high-quality anode copper. The qualified anode copper produced enters the anode casting machine through the chute. The produced refined slag is discharged into the slag bag in an organized manner, and after cooling and crushing, it is returned to the smelting or converting furnace as cold material. The flue gas obtained from refining in the rotary anode furnace is discharged after meeting the standards through the flue gas treatment system.

[0041] Anode copper is electrolyzed to obtain high-purity copper cathode plates and anode mud. Gold, silver, etc. are present in the anode mud. Metals such as gold, silver, platinum and palladium are recovered from the anode mud. The platinum and palladium concentrate is sold or further refined into pure platinum and pure palladium.

[0042] In some preferred embodiments of the present application, organic matter from waste circuit boards is burned into flue gas, which is then treated and dust collected to produce acid, and other impurity elements enter the slag. The total recovery rate of copper is >98%, thereby maximizing the recovery of valuable metals in copper-containing sludge, waste circuit boards, and copper concentrate.

[0043] The smoke and dust produced during the above entire smelting process can be directly fed into the smelting furnace or can be pelletized and then fed into the smelting furnace.

[0044] The beneficial effects of the present application are further illustrated below with reference to the following embodiments and comparative examples.

[0045] Example 1

[0046] refer to Figure 1 The continuous copper smelting process shown in the figure is combined with the treatment process flow diagram of waste circuit boards and copper-containing sludge:

[0047] In step S1, the copper-containing sludge is dried to a water content of 10%, the waste circuit boards are detinned (the tin content after detinning is 3%) and crushed to 50 mm, and a bottom blowing + bottom blowing continuous blowing process is adopted. The annual processing capacity is 500,000 tons of copper concentrate, 20,000 tons of dry basis copper-containing sludge (10% water content entering the furnace), and 40,000 tons of detinned waste circuit boards. Copper concentrate, copper-containing sludge, crushed scrap circuit boards, quartz stone, and smelting slag (8% by weight of the copper concentrate) are mixed and added to a bottom-blown smelting furnace. Oxygen-enriched air (80% oxygen content) is blown into the furnace to react with the copper concentrate and burn the scrap circuit boards, providing heat for smelting. The 20% by weight of calcium in the copper-containing sludge reacts with chlorine to form calcium chloride, which fixes the chlorine in the slag, reducing the chlorine required for dioxin production during flue gas cooling. After the reaction is complete, heavy metals such as gold, silver, and platinum enter the copper matte, while the chlorine, quartz stone, iron, silicon, and calcium in the copper-containing sludge, iron in the scrap circuit boards, and iron in the copper concentrate form slag. The copper matte (copper grade of 75% and recovery rate of gold, silver, platinum, and palladium exceeding 99%) is separated from the smelting slag and settles to the bottom. The organic dioxin content in the flue gas and dust from the bottom-blown smelting furnace is 0.05 ng TEQ / m 3 After the waste heat recovery treatment of the boiler, dust collection, and flue gas acidification treatment, it enters the tail gas absorption tower for treatment and is then discharged. The dioxin content in the exhaust flue gas is 0.016ng TEQ / m 3 , in compliance with national regulations.

[0048] In step S2, 65% of the copper matte is continuously discharged into a bottom-blown continuous converting furnace in an oxygen-containing atmosphere with an oxygen content of 30%, and is converted with 5mm lump coal (lump coal ratio is 0.5%) and a slag-forming agent (ferrosilicon slag, Fe / SiO2=1:1) to obtain blister copper (98.7%), converting slag, and flue gas dust. Precious metals such as gold, silver, and platinum are enriched in the blister copper. The flue gas and dust are sequentially subjected to boiler waste heat recovery treatment, dust collection, and flue gas acid production treatment to obtain exhaust flue gas. No dioxins are generated in the flue gas and dust.

[0049] Step S3: Refining the casting waste plate, natural gas and crude copper in oxygen-enriched air (oxygen content is 60%) in a rotary anode furnace to obtain anode copper, refined slag and flue gas.

[0050] In step S4, anode copper is electrolyzed to obtain a copper cathode plate and anode mud, and precious metals such as gold, silver, platinum, and palladium are recovered from the anode mud. The total recovery rates of gold, silver, and copper are shown in Table 1.

[0051] Example 2

[0052] In step S1, the copper-containing sludge is dried to a water content of 15%, the waste circuit boards are detinned (the tin content after detinning is 5%) and crushed to 10mm, and a side-blowing + multi-gun top-blowing refining process is adopted. The annual processing capacity is 1 million tons of copper concentrate, 60,000 tons of dry-based copper-containing sludge (10% water content entering the furnace), and 100,000 tons of detinned waste circuit boards. Copper concentrate, copper-containing sludge, crushed scrap circuit boards, quartz stone, and smelting slag (5% by weight of the copper concentrate) are added to a side-blown smelting furnace after batching. Oxygen-enriched air (90% oxygen content) is blown into the side-blown smelting furnace to react with the copper concentrate and burn the scrap circuit boards, providing heat for smelting. 20% by weight of calcium in the copper-containing sludge reacts with chlorine to form calcium chloride, which fixes the chlorine in the slag, reducing the chlorine required for dioxin production during flue gas cooling. After the reaction is complete, heavy metals such as gold, silver, and platinum enter the copper matte, while chlorine, quartz stone, iron, silicon, and calcium in the copper-containing sludge, iron in the scrap circuit boards, and iron in the copper concentrate form slag. The copper matte (copper grade of 75% and recovery rate of gold, silver, platinum, and palladium exceeding 99%) separates from the smelting slag and settles to the bottom. The organic dioxin content in the flue gas and dust from the side-blown smelting furnace is 0.032 ng TEQ / m 3 After the waste heat recovery treatment of the boiler, dust collection, and flue gas acidification treatment, it enters the tail gas absorption tower for treatment and is then discharged. The dioxin content in the exhaust flue gas is 0.01ng TEQ / m 3 , in compliance with national regulations.

[0053] In step S2, 65% of the copper matte is continuously discharged into a multi-lance top-blowing converting furnace in an oxygen-containing atmosphere with an oxygen content of 34%, and is converted with 10 mm lump coal (lump coal ratio is 1%) and a slag-forming agent (ferro-calcium slag, Fe / CaO = 2.3:1) to produce blister copper (98.7%), converting slag, and flue gas dust. Precious metals such as gold, silver, and platinum are enriched in the blister copper. The flue gas dust is then subjected to boiler waste heat recovery, dust collection, and flue gas acidification treatment in sequence to produce exhaust flue gas. No dioxins are generated in the flue gas dust.

[0054] Step S3: Refining the casting waste plate, natural gas and crude copper in oxygen-enriched air (oxygen content is 60%) in a rotary anode furnace to obtain anode copper, refined slag and flue gas.

[0055] In step S4, anode copper is electrolyzed to obtain a copper cathode plate and anode mud, and precious metals such as gold, silver, platinum, and palladium are recovered from the anode mud. The total recovery rates of gold, silver, and copper are shown in Table 1.

[0056] Example 3

[0057] The difference from Example 1 is that in step S1, the feed ratio of copper-containing sludge, waste circuit boards, and copper concentrate is 6:10:100, and copper cathode plates and anode mud are finally obtained.

[0058] Example 4

[0059] The difference from Example 1 is that in step S1, the feed ratio of copper-containing sludge, waste circuit boards, and copper concentrate is 4:6:80, and copper cathode plates and anode mud are finally obtained.

[0060] Example 5

[0061] The difference from Example 1 is that in step S1, the feed ratio of copper-containing sludge, waste circuit boards, and copper concentrate is 1:4:40, and copper cathode plates and anode mud are finally obtained.

[0062] Example 6

[0063] The difference from Example 2 is that in step S2, the Fe / CaO ratio in the ferro-calcium slag is 2.3:1, and finally a copper cathode plate and anode mud are obtained.

[0064] Example 7

[0065] The difference from Example 2 is that in step S2, the Fe / CaO ratio in the ferro-calcium slag is 2.5:1, and finally a copper cathode plate and anode mud are obtained.

[0066] Example 8

[0067] The difference from Example 2 is that in step S2, the Fe / CaO ratio in the ferro-calcium slag is 2.2:1, and finally a copper cathode plate and anode mud are obtained.

[0068] Example 9

[0069] The difference from Example 1 is that in step S2, the Fe / SiO2 in the ferrosilicon slag is 1.2:1, and finally a copper cathode plate and anode mud are obtained.

[0070] Example 10

[0071] The difference from Example 1 is that in step S2, the Fe / SiO2 in the ferrosilicon slag is 1.5:1, and finally a copper cathode plate and anode mud are obtained.

[0072] Example 11

[0073] The difference from Example 2 is that, in step S1, the copper-containing sludge is dried to a water content of 15%, the waste circuit boards are detinned (the tin content after detinning is 3%) and crushed to 30mm, and a side-blowing + multi-gun top-blowing blowing process is adopted. The annual processing capacity is 1 million tons of copper concentrate, 60,000 tons of dry-based copper-containing sludge (10% water content entering the furnace), and 100,000 tons of detinned waste circuit boards. Copper concentrate, copper-containing sludge, crushed waste circuit boards, quartz stone, smelting slag (8wt% of copper concentrate) and other materials are added to the side-blowing smelting furnace after batching; oxygen-enriched air (oxygen content of 60%) is blown into the side-blowing smelting furnace to react with copper concentrate and burn waste circuit boards to provide heat for smelting. 10wt% of calcium in the copper-containing sludge reacts with chlorine to form calcium chloride to fix the chlorine in the slag, reducing the chlorine required to produce dioxins during the flue gas cooling process; after the reaction is completed, gold and silver Heavy metals such as platinum enter the copper matte, and chlorine, quartz stone, iron, silicon, calcium in copper-containing sludge, iron in waste circuit boards, and iron in copper concentrate form slag; the copper matte (copper grade is 80%, and the recovery rate of gold, silver, platinum and palladium reaches more than 99%) is separated from the smelting slag and settles at the bottom. The flue gas and dust in the side-blown smelting furnace are treated by boiler waste heat recovery, dust collection, and flue gas acid production, and then enter the tail gas absorption tower for treatment and then discharged. The exhaust flue gas obtained meets national regulations, and finally copper cathode plates and anode mud are obtained.

[0074] Example 12

[0075] The difference from Example 2 is that in step S2, 73% of the copper matte is continuously discharged into a multi-lance top-blowing converting furnace in an oxygen-containing atmosphere with an oxygen content of 24%, and is converted with 5 mm lump coal and a slag-forming agent (ferro-calcium slag, Fe / CaO=2.3:1) to obtain blister copper (99%), converting slag, and flue gas dust. Precious metals such as gold, silver, and platinum are enriched in the blister copper. The flue gas and dust are sequentially subjected to boiler waste heat recovery treatment, dust collection, and flue gas acid production treatment to obtain exhaust flue gas, wherein no dioxins are generated in the flue gas and dust.

[0076] Example 13

[0077] The difference from Example 2 is that, in step S3, the casting waste plate, natural gas and crude copper are refined in oxygen-enriched air (oxygen content is 90%) in a rotary anode furnace to obtain anode copper, refined slag and flue gas, and finally obtain copper cathode plates and anode mud.

[0078] The total recovery rates of gold, silver, and copper in Examples 1 to 13, as well as the dioxin contents in the flue gas and dust and the exhaust gas in step S1, were measured, and the results are shown in Table 1 below.

[0079] Table 1

[0080]

[0081]

[0082] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0083] The above method of the present application is intended to simultaneously treat hazardous waste waste circuit boards and copper-containing sludge during the copper smelting process, achieving efficient and green comprehensive recovery of valuable metals such as copper, gold, and silver, and reducing storage and processing costs. Specifically, with the help of the high temperature conditions and oxygen-rich air generated by the excess heat in the copper smelting process, the elemental sulfur produced by the decomposition of copper concentrate is fully utilized as a reducing agent. The reducing agent reduces copper and other valuable metal oxides in the copper-containing sludge to copper matte. The high temperature conditions of the copper smelting process are used to promote the combustion of organic matter in the waste circuit boards, reducing the difficulty and cost of disposing of the waste circuit boards. At the same time, heat is generated, thereby avoiding the need for a large amount of carbonaceous reducing agent or fuel to treat the copper-containing sludge alone; and the calcium in the copper-containing sludge is used as a curing agent to solidify the chlorine in the waste circuit boards, inhibiting the chloride required for dioxin production during the flue gas cooling process, producing harmless flue gas, and effectively improving the environment. At the same time, the high temperature conditions of the copper smelting process are used to treat the copper-containing sludge, while recovering the valuable metals therein, and smelting other substances into pyrometallurgical slag to become general solid waste. The harmless tailings produced are used in cement plants as additives. As can be seen, the above method can successfully achieve the goal of large-scale, harmless, and low-cost disposal of hazardous waste, while also recovering valuable metal elements. This makes the method of treating waste circuit boards in conjunction with continuous copper smelting a green, environmentally friendly, safe, reliable, and economically efficient process. Furthermore, the above method does not require complex pretreatment of the raw materials, avoiding the problems of prior art wet treatment methods that produce waste acid and waste residue, and the need for additional fuel such as coal due to low oxygen concentration. Furthermore, it helps fully utilize the continuous copper smelting equipment and treat the aforementioned hazardous waste at a low equipment cost.

[0084] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for treating waste circuit boards and copper-containing sludge in a continuous copper smelting process, characterized in that: The method comprises: Step S1: Smelting raw materials including copper-containing sludge, waste circuit boards, copper concentrate, and flux in oxygen-enriched air to obtain copper matte, smelting slag, and flue gas and dust; the feed ratio of the copper-containing sludge, the waste circuit boards, and the copper concentrate is 2-6: 4-10: 50-100, calculated on a dry basis of the copper-containing sludge; the copper grade in the copper matte is 65-75%, the gold and silver capture rates reach above 98%, and the platinum and palladium capture rates reach above 99%; Step S2, continuously blowing the raw materials including the copper matte, fuel, and slagging agent in an oxygen-containing atmosphere to obtain blister copper, blowing slag, and flue gas and dust; Step S3, refining the blister copper in a rotary anode furnace to obtain anode copper, refined slag and flue gas; and Step S4: electrolyzing the anode copper to obtain a copper cathode plate and anode mud.

2. The method according to claim 1, characterized in that The step S1 also includes the steps of pre-detinning and crushing the waste circuit boards.

3. The method according to claim 2, characterized in that The particle size of the crushed waste circuit boards is 10-50 mm.

4. The method according to claim 2, characterized in that The tin content of the crushed waste circuit boards is 3-5%.

5. The method according to claim 2, characterized in that The step S1 also includes the step of pre-dehydrating the copper-containing sludge.

6. The method according to claim 5, characterized in that The moisture content of the copper-containing sludge after dehydration is 10-15%.

7. The method according to claim 1 or 2, characterized in that The method further includes: subjecting the flue gas and dust in step S1 to boiler waste heat recovery treatment, dust collection, and flue gas acid production treatment in sequence to obtain exhaust flue gas.

8. The method according to claim 7, characterized in that The dioxin content of the flue gas and dust in step S1 is 0.032-0.05 ng TEQ / m 3 .

9. The method according to claim 7, characterized in that The dioxin content in the exhaust gas in step S1 is 0.008-0.012 ng TEQ / m 3 .

10. The method according to claim 1, characterized in that In step S1, the raw materials further include cold material, and the cold material is 5-8 wt% of the copper concentrate.

11. The method according to claim 10, characterized in that The cold material is selected from any one or more of blowing slag, slag concentrate, and refined slag.

12. The method according to claim 10, characterized in that In step S1, the volume content of oxygen in the oxygen-enriched air is 60-90%.

13. The method according to claim 10, characterized in that The flux is 10-15 wt% of the copper concentrate.

14. The method according to claim 10, characterized in that The flux is selected from any one or more of quartz stone, quicklime, dolomite and quartz sand.

15. The method according to claim 14, characterized in that The flux is quartz stone.

16. The method according to claim 10, characterized in that The smelting is selected from any one of bottom blowing smelting, side blowing smelting and top blowing smelting.

17. The method according to claim 10, wherein: The smelting is carried out in a smelting furnace.

18. The method according to claim 1, wherein In step S2, the volume content of oxygen in the oxygen-containing atmosphere is 24-34%.

19. The method according to claim 18, characterized in that In step S2, the fuel is lump coal.

20. The method according to claim 19, characterized in that The lump coal rate of the lump coal is 0.5-1%.

21. The method according to claim 19, wherein The particle size of the lump coal is 5-15 mm.

22. The method according to claim 1, wherein The method further comprises: The flue gas and dust in step S2 are sequentially subjected to boiler waste heat recovery treatment, dust collection, and flue gas acid production treatment to obtain exhaust flue gas.

23. The method according to claim 22, characterized in that The blown slag is returned to step S1 as part of the cold material, and / or the blown slag is returned to step S2 as part of the cold material.

24. The method according to claim 22, characterized in that The continuous blowing is bottom blowing or multi-lance top blowing.

25. The method according to claim 22, wherein The continuous blowing is carried out in a blowing furnace.

26. The method according to claim 1, wherein In the step S2, when the continuous blowing is bottom blowing, the slagging agent is ferrosilicon slag.

27. The method according to claim 26, characterized in that The Fe / SiO2 in the ferrosilicon slag is 0.8~1.2:

1.

28. The method according to claim 1, wherein When the continuous blowing is multi-lance top blowing, the slagging agent is ferro-calcium slag.

29. The method according to claim 28, characterized in that The Fe / CaO in the ferro-calcium slag is 2.3-2.5:

1.

30. The method according to claim 1, wherein The copper content of the crude copper is greater than 98.5%.

31. The method according to claim 1, wherein When the smelting is bottom-blowing smelting, the total recovery rate of gold reaches more than 98%, and the total recovery rate of silver reaches more than 97%.

32. The method according to claim 1, wherein When the smelting is side-blowing smelting, the total recovery rate of gold reaches more than 97%, and the total recovery rate of silver reaches more than 96%.

33. The method according to claim 1, wherein In step S3, the spent anode, fuel and oxygen-enriched air are subjected to the rotary anode furnace refining.

34. The method according to claim 33, wherein The spent anodes are cast waste plates and / or scrap anodes.

35. The method according to claim 33, wherein The fuel in step S3 is selected from any one or more of natural gas, diesel, and pulverized coal.

36. The method according to claim 33, wherein The volume content of oxygen in the oxygen-enriched air in step S3 is 60-90%.

37. The method according to claim 33, wherein The refined slag is returned to the step S1 as part of the cold material, and / or the refined slag is returned to the step S2 as part of the cold material.

38. The method according to claim 1, wherein The total recovery rate of copper is >98%.

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