Method and system for treating copper-containing sludge

Abstract

The present invention discloses a method and system for treating copper-containing sludge, the method comprising: drying the copper-containing sludge to obtain dried copper-containing sludge and flue gas; smelting the dried copper-containing sludge, copper slag, flux or iron tailings, and reducing agent to obtain matte, tailings, and high-temperature flue gas. The method makes full use of the complementarity of the components of copper-containing sludge and copper slag, significantly reduces the amount of flux and reducing agent used, and at the same time eliminates the sulfiding agent, significantly improves the depletion effect of copper slag, and realizes the resource recycling of multiple metals such as copper, nickel, lead, zinc, tin, etc. in copper-containing sludge and copper slag, and also significantly reduces the solid waste content.

Description

Technical Field

[0001] The present invention belongs to the technical field of copper-containing sludge treatment, and in particular, relates to a method and a system for treating copper-containing sludge. Background Art

[0002] The copper-containing sludge after the electroplating process wastewater treatment contains a large amount of valuable metal elements (such as copper, nickel, tin, etc.), but the types and contents of components in the sludge produced by different processes vary greatly. Generally, the sludge with a high copper content (10-20wt%) can be dried, dehydrated and added with a certain amount of flux before entering the blast furnace for reduction smelting. The resulting black copper, matte and other products can enter the main copper smelting process. The copper content of the tailings is generally about 0.8wt%, and the smelting slag is mainly FeO-SiO2-CaO. When treating copper-containing sludge with low CaSO4, only a small amount of flux needs to be added to adjust the composition to obtain the target slag type. However, sulfuric acid is often used in the electroplating process and is neutralized with cheap lime. Therefore, the sludge generally contains a large amount of calcium sulfate. For this type of high-calcium, low-silicon, and low-iron copper-containing sludge, the relevant process needs to add a large amount of flux such as silica and iron ore. The amount of flux added exceeds 50% of the total mass of the dry sludge, which significantly increases the slag volume. The method of mixing with other high-silicon sludge will reduce the copper content in the raw material, and the mixing ratio is low and the processing capacity is small. Therefore, the existing process for treating high-calcium, low-silicon, and low-iron copper-containing sludge consumes a lot of raw materials and energy, and has poor feasibility.

[0003] The slag produced during the bottom blowing copper smelting process is mainly FeO-SiO2, with a high copper content (about 5wt%). It is generally treated by flotation and electric furnace reduction. The resulting matte is returned for blowing, and the tailings are stored or used as building materials. The flotation method requires the copper slag to be slowly cooled, and then the copper concentrate is separated through processes such as crushing, grinding, flotation, filter pressing, and thickening. The resulting abandoned slag contains about 0.3wt% copper; while when the electric furnace is used for reduction and depletion, the slag is mainly composed of a binary slag system of FeO-SiO2, and flux (such as lime, silica, etc.), a reducing agent and a sulfiding agent (such as pyrite) need to be added to the molten pool to achieve the purpose of reduction and sulfidation. The resulting tailings contain 0.5-1.0wt% copper, but the addition of flux will lead to problems such as increased processing costs and large slag volume, so flux is generally added less or not.

[0004] In the related art, there is a process of mixing copper slag, copper-containing sludge and a reducing agent, then reducing and smelting to obtain alloys and ferrochrome slag, and then recovering various valuable metals in the alloy through electrolytic treatment. The copper-containing sludge treated by this process basically does not contain CaSO4, and can only treat copper-containing sludge with a main composition similar to that of copper slag. The raw material adaptability is poor, and it cannot treat high-calcium, low-silicon, and low-iron copper-containing sludge. There is also a process of pre-mixing copper-containing sludge with flux and reducing agent, and then smelting at high temperature to obtain metal melt and copper slag, but the raw materials used in this process contain almost no sulfur, no matte is produced, and the total mass of flux and reducing agent consumption is almost the same as the mass of dry sludge treated, which not only consumes a large amount of flux and reducing agent, but also leads to an increase in the total amount of slag, and has poor feasibility.

[0005] Therefore, the existing technology for treating copper-containing sludge needs to be further improved. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one object of the present invention is to provide a method and system for treating copper-containing sludge. The method makes full use of the complementarity of the components of copper-containing sludge and copper slag, significantly reduces the amount of flux and reducing agent used, and at the same time eliminates the sulfiding agent, significantly improves the depletion effect of copper slag, and realizes the resource recycling of various metals such as copper, nickel, lead, zinc, tin, etc. in copper-containing sludge and copper slag, and also significantly reduces the solid waste content.

[0007] In one aspect of the present invention, the present invention provides a method for treating copper-containing sludge, wherein CaO / SiO2>3, Fe / CaO<0.67 in the copper-containing sludge. According to an embodiment of the present invention, the method comprises:

[0008] Drying the copper-containing sludge to obtain dried copper-containing sludge and flue gas;

[0009] The dried copper-containing sludge, copper slag, flux and reducing agent are smelted to obtain matte, tailings and high-temperature flue gas.

[0010] According to the method for treating copper-containing sludge in an embodiment of the present invention, the dried copper-containing sludge is used in combination with copper slag, and assisted by flux or iron tailings and reducing agent. FeO and SiO2 in the copper slag can form a FeO-SiO2-CaO ternary slag system under the joint action of CaSO4, reducing agent and flux or iron tailings in the copper-containing sludge, and the sulfur element in the copper-containing sludge can promote the enrichment of Cu, Ni, Sn and the like in the copper slag and the copper-containing sludge into matte, so that the produced matte can be used in the main process of copper smelting, and the copper content in the obtained tailings can be reduced to below 0.5wt%, which can be used as a raw material for building materials. The obtained smoke is rich in lead, zinc and tin, which is conducive to subsequent recycling. Thus, the method makes full use of the complementarity of the components of copper-containing sludge and copper slag, significantly reduces the amount of flux and reducing agent used, and eliminates the sulfiding agent, significantly improves the depletion effect of copper slag, and realizes the resource recycling of copper, nickel, lead, zinc, tin and other metals in copper-containing sludge and copper slag. The grade of the obtained matte is 40-60%, the copper recovery rate exceeds 96%, and the contents of copper, nickel, lead, zinc and tin in the tailings are respectively lower than 0.5wt%, 0.1wt%, 0.1wt%, 0.6wt% and 0.3wt%, which also significantly reduces the total mass of solid waste. The mass of the obtained tailings only accounts for 40-60% of the total mass of copper-containing sludge and copper slag. In the embodiment of the present invention, iron tailings can also be used instead of flux, and the iron tailings itself is a solid waste, wherein SiO2 can replace silica flux, and iron can replace iron element in copper slag. Using iron tailings instead of flux can not only provide a new treatment method for iron tailings solid waste, but also help to adjust the slag composition.

[0011] In addition, the method for treating copper-containing sludge according to the above embodiment of the present invention may also have the following additional technical features:

[0012] In some embodiments of the present invention, the TFe content in the copper-containing sludge is 2-10wt%, the CaO content is 15-30wt%, the SiO2 content is 0-5wt%, the Al2O3 content is 0-3wt%, the Cu content is greater than 10wt%, the Ni content is 0-0.5wt%, the Sn content is 0-1wt%, the S content is greater than 10wt%, and the C content is 2-10wt%, calculated on a dry basis of the copper-containing sludge.

[0013] In some embodiments of the present invention, the mass ratio of the copper-containing sludge to the copper slag and the flux reducing agent is 100:10-50:2-10:5-10, or the mass ratio of the copper-containing sludge to the copper slag, iron tailings and reducing agent is 100:10-50:5-30:5-10, calculated on a dry basis of the copper-containing sludge;

[0014] In some embodiments of the present invention, the sum of the masses of the flux and the reducing agent is no more than 15% of the sum of the masses of the copper-containing sludge and the copper slag, and the mass of the copper-containing sludge is calculated as wet material.

[0015] In some embodiments of the present invention, the copper slag is bottom-blown copper smelting slag.

[0016] In some embodiments of the present invention, the copper slag contains 35-45wt% TFe, 0-5wt% CaO, 20-30wt% SiO2, 0-3wt% MgO, 0-5wt% Al2O3, 1-5wt% Cu, 0-1wt% Pb, 0-5wt% Zn and 1-3wt% S.

[0017] In some embodiments of the present invention, the reducing agent is selected from at least one of coal and coke.

[0018] In some embodiments of the present invention, the flux is silica.

[0019] In some embodiments of the present invention, the iron tailings contain 10-20wt% TFe, 1-5wt% CaO, 50-75wt% SiO2, 1-5wt% MgO and 1-10wt% Al2O3.

[0020] In some embodiments of the present invention, the tailings contain CaO / SiO2=0.7-1.1, Fe / SiO2=0.5-1.2, Fe 3+ / Fe 2+ =0.09-0.11.

[0021] In some embodiments of the present invention, the temperature of the smelting process is 1250-1450°C.

[0022] In some embodiments of the present invention, the method for treating copper-containing sludge further comprises: using the high-temperature flue gas to dry the copper-containing sludge.

[0023] In some embodiments of the present invention, the method for treating copper-containing sludge further comprises: subjecting the flue gas to dust collection treatment to obtain flue dust containing lead, zinc and tin.

[0024] In yet another aspect of the present invention, the present invention provides a system suitable for the above-mentioned method for treating copper-containing sludge. According to an embodiment of the present invention, the system comprises:

[0025] A drying device, the drying device having a copper-containing sludge inlet, a dried copper-containing sludge outlet and a flue gas outlet;

[0026] A smelting device, wherein the smelting device has an inlet for dried copper-containing sludge, a copper slag inlet, a flux or iron tailings inlet, a reducing agent inlet, a matte outlet, a tailings outlet and a high-temperature flue gas outlet, and the inlet for dried copper-containing sludge is connected to the outlet for dried copper-containing sludge.

[0027] According to the system for treating copper-containing sludge of an embodiment of the present invention, by using copper-containing sludge in combination with copper slag, and supplemented with flux or iron tailings and reducing agent, FeO and SiO2 in the copper slag can form a FeO-SiO2-CaO ternary slag system under the joint action of CaSO4, reducing agent and flux or iron tailings in the copper-containing sludge, and the sulfur element in the copper-containing sludge can promote the enrichment of Cu, Ni, Sn and the like in the copper slag and the copper-containing sludge into matte, so that the produced matte can be used in the main process of copper smelting, and the copper content in the obtained tailings can be reduced to below 0.5wt%, which can be used as a raw material for building materials, and the obtained smoke is rich in lead, zinc and tin, which is conducive to subsequent recycling. Therefore, the system makes full use of the complementarity of the components of copper-containing sludge and copper slag, significantly reduces the use of flux and reducing agent, saves sulfiding agent, significantly improves the depletion effect of copper slag, and realizes the resource recycling of copper, nickel, lead, zinc, tin and other metals in copper-containing sludge and copper slag. The grade of the obtained matte is 40-60%, the copper recovery rate exceeds 96%, and the contents of copper, nickel, lead, zinc and tin in the tailings are less than 0.5wt%, 0.1wt%, 0.1wt%, 0.6wt% and 0.3wt%, respectively. Furthermore, the system only combines the drying device with the smelting device to treat the copper-containing sludge, which significantly reduces the equipment investment and operation costs.

[0028] In addition, the system for treating copper-containing sludge according to the above embodiment of the present invention may also have the following additional technical features:

[0029] In some embodiments of the present invention, the high-temperature flue gas outlet is connected to the drying device.

[0030] In some embodiments of the present invention, the system for treating copper-containing sludge further includes: a dust collecting device having a smoke inlet and a smoke outlet containing lead, zinc and tin, and the smoke inlet is connected to the smoke outlet.

[0031] In some embodiments of the present invention, the drying device is selected from at least one of a rotary kiln and a tunnel kiln.

[0032] In some embodiments of the present invention, the smelting device is a depleted electric furnace.

[0033] In some embodiments of the present invention, the dust collecting device is a multi-stage dust removal device.

[0034] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0036] Figure 1 is a schematic flow chart of a method for treating copper-containing sludge according to an embodiment of the present invention;

[0037] Figure 2 is a schematic flow chart of a method for treating copper-containing sludge according to another embodiment of the present invention;

[0038] Figure 3 is a schematic flow chart of a method for treating copper-containing sludge according to another embodiment of the present invention;

[0039] Figure 4 is a side view of the system structure for treating copper-containing sludge according to one embodiment of the present invention;

[0040] Figure 5 is a side view of the system structure for treating copper-containing sludge according to another embodiment of the present invention;

[0041] Figure 6 yes Figure 5 A top view of the system for treating copper-containing sludge;

[0042] Figure 7 It is a side view of the system structure for treating copper-containing sludge according to another embodiment of the present invention. DETAILED DESCRIPTION

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0044] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In one aspect of the present invention, the present invention provides a method for treating copper-containing sludge, wherein CaO / SiO2>3, Fe / CaO<0.67, that is, the copper-containing sludge described in the present application is high-calcium, low-silicon, low-iron type copper-containing sludge, and the Cu, Fe, Ca, S, and C in the copper-containing sludge are mainly in the form of sulfate (CuSO4), ferrous silicate (Fe2SiO4), calcium sulfate (CaSO4), sulfate (SO4 2- ), organic matter (C x H y O z ) form. According to an embodiment of the present invention, reference Figure 1 , the method comprising:

[0046] S100: Drying of copper-containing sludge

[0047] In this step, the copper-containing sludge is dried to reduce the moisture in the copper-containing sludge, so as to obtain the dried copper-containing sludge and flue gas. It should be noted that before drying, the copper-containing sludge can be pre-treated, such as filtering, drying and other processes, to preliminarily remove the moisture in the copper-containing sludge. Further, the moisture content of the copper-containing sludge used for drying is not particularly limited, and those skilled in the art can select it according to actual needs, such as about 30wt%. As a result, it is beneficial to save energy consumption during drying treatment, and the energy consumption of pre-treatment is not too high, which is beneficial to reduce overall energy consumption. Further, the temperature of the drying treatment is not particularly limited, and those skilled in the art can select it according to actual needs, such as 600°C.

[0048] According to one embodiment of the present invention, the content of each component in the copper-containing sludge is not particularly limited, such as the content of TFe can be 2-10wt%, the content of CaO can be 15-30wt%, the content of SiO2 can be 0-5wt%, the content of Al2O3 can be 0-3wt%, the content of Cu can be greater than 10wt%, the content of Ni can be 0-0.5wt%, the content of Sn can be 0-1wt%, the content of S can be greater than 10wt%, and the content of C can be 2-10wt%, calculated on a dry basis of the copper-containing sludge.

[0049] S200: Smelting the dried copper-containing sludge, copper slag, flux or iron tailings, and reducing agent

[0050] In this step, the dried copper-containing sludge, copper slag, flux or iron tailings, and reducing agent are smelted to obtain matte copper, tailings, and high-temperature flue gas. The inventors found that during the smelting process, FeO and SiO2 in the copper slag can form a FeO-SiO2-CaO ternary slag system under the joint action of CaSO4, reducing agent, and flux in the copper-containing sludge, and the sulfur element in the copper-containing sludge can promote the enrichment of Cu, Ni, Sn, etc. in the copper slag and the copper-containing sludge into matte copper, so that the produced matte copper can be used in the main process of copper smelting, and the copper content in the obtained tailings can be reduced to less than 0.5wt%, which can be used as a raw material for building materials, and the obtained smoke is rich in lead, zinc, and tin, which is conducive to subsequent recycling. That is, the smelting makes full use of the complementarity of the components of copper-containing sludge and copper slag, significantly reduces the amount of flux and reducing agent used, and eliminates the sulfiding agent, significantly improves the depletion effect of copper slag, and realizes the resource recycling of copper, nickel, lead, zinc, tin and other metals in copper-containing sludge and copper slag. The grade of the obtained matte is 40-60%, the copper recovery rate exceeds 96%, and the contents of copper, nickel, lead, zinc and tin in the tailings are respectively less than 0.5wt%, 0.1wt%, 0.1wt%, 0.6wt% and 0.3wt%. In the embodiment of the present invention, iron tailings can also be used instead of flux. The iron tailings itself is a solid waste, and SiO2 can replace silica flux, and iron can replace iron element in copper slag. Using iron tailings instead of flux can not only provide a new treatment method for iron tailings solid waste, but also help adjust the slag composition.

[0051] According to one embodiment of the present invention, the mass ratio of copper-containing sludge to copper slag, flux or iron tailings, and reducing agent is not particularly limited, and those skilled in the art can select it according to actual needs. For example, the mass ratio of copper-containing sludge to copper slag, flux, and reducing agent can be 100:10-50:2-10:5-10, or the mass ratio of copper-containing sludge to copper slag, iron tailings, and reducing agent can be 100:10-50:5-30:5-10, calculated on a dry basis of copper-containing sludge. Specifically, the mass ratio of copper-containing sludge to copper slag, flux, and reducing agent can be 100: 10 / 20 / 30 / 40 / 50: 2 / 4 / 6 / 8 / 10: 5 / 6 / 7 / 8 / 9 / 10, or the mass ratio of copper-containing sludge to copper slag, iron tailings, and reducing agent can be 100: 10 / 20 / 30 / 40 / 50: 5 / 10 / 15 / 20 / 25 / 30: 5 / 6 / 7 / 8 / 9 / 10. Further, the sum of the mass of the flux and the reducing agent may not be greater than 15% of the sum of the mass of the copper-containing sludge and the copper slag, and the copper-containing sludge is calculated as wet material. The inventors have found that because the components in the copper-containing sludge and the copper slag are complementary, the amount of flux and reducing agent used is significantly reduced, avoiding the problem of solid waste volume increase caused by a large amount of flux ratio, and the tailings slag type can also be optimized under the above-mentioned flux usage, reducing the copper content in the tailings. Specifically, the amount of flux and reducing agent used can be selected and added according to the content of each component in the copper-containing sludge and copper slag to promote the recovery of valuable metal elements.

[0052] According to another embodiment of the present invention, the copper slag can be bottom-blown copper smelting slag to achieve the recycling of solid waste, and the Fe in the copper slag mainly exists in the form of FeO and Fe3O4, and the Cu mainly exists in the form of Cu2S and metal Cu. Further, the content of each component in the copper slag is not particularly limited, such as the content of TFe in the copper slag can be 35-45wt%, the content of CaO can be 0-5wt%, the content of SiO2 can be 20-30wt%, the content of MgO can be 0-3wt%, the content of Al2O3 can be 0-5wt%, the content of Cu can be 1-5wt%, the content of Pb can be 0-1wt%, the content of Zn can be 0-5wt%, and the content of S can be 1-3wt%. The copper slag is smelted together with the above-mentioned copper-containing sludge. The components in the copper slag can complement the components in the copper-containing sludge to form a FeO-SiO2-CaO ternary slag system. At the same time, it can also promote the enrichment of Cu, Ni, Sn and the like in the copper slag and the copper-containing sludge into matte, so that the copper content in the obtained tailings can be reduced to below 0.5wt%, and the obtained smoke is rich in lead, zinc and tin.

[0053] According to another embodiment of the present invention, the specific types of reducing agent, flux or iron tailings are not particularly limited. For example, the reducing agent can be selected from at least one of coal and coke, and the flux can be silica. The inventors found that the reducing agent can promote the reduction of calcium sulfate to CaS. When the reducing agent is present during the smelting process, Fe2O3 in the copper slag can react with CaS, 2CaS+Fe2O3+C=2CaO+2FeS+CO, and the produced FeS enters the matte phase. CaO combines with SiO2 in the flux or iron tailings to form calcium silicate, which can adjust the basicity of the slag and improve the slag melting performance. Further, the content of each component in the iron tailings is not particularly limited. For example, the content of TFe can be 10-20wt%, the content of CaO can be 1-5wt%, the content of SiO2 can be 50-75wt%, the content of MgO can be 1-5wt%, and the content of Al2O3 can be 1-10wt%. In the embodiments of the present invention, iron tailings are used instead of flux. The iron tailings itself is a kind of solid waste. SiO2 in the iron tailings can replace silica flux, and iron can replace the iron element in copper slag. Using iron tailings instead of flux can not only provide a new treatment method for iron tailings solid waste, but also help to adjust the slag composition.

[0054] According to another embodiment of the present invention, the method for treating copper-containing sludge of the present application is adopted, and the ratio of raw materials is controlled so that CaO / SiO2=0.7-1.1, Fe / SiO2=0.5-1.2, Fe 3+ / Fe 2+ =0.09-0.11. The inventors found that within this composition range, the slag has good properties, mainly in that the slag has a lower melting point and a lower viscosity, which can reduce the smelting temperature, is conducive to the separation of the slag and the matte, and the dissolved copper content in the slag is low.

[0055] According to another embodiment of the present invention, the temperature of the smelting process can be 1250-1450° C. Specifically, during the smelting process, the temperature near the high-temperature flue gas outlet can be controlled in a higher range, such as 1250-1450° C., to promote the volatilization of lead, zinc, and tin, while the composition of the matte and tailings near the matte and tailings outlet tends to be stable, and the temperature thereof can be controlled in a lower range, such as 1250-1300° C.

[0056] According to the method for treating copper-containing sludge in an embodiment of the present invention, copper-containing sludge is used in combination with copper slag, and assisted by flux and reducing agent. FeO and SiO2 in the copper slag can form a FeO-SiO2-CaO ternary slag system under the joint action of CaSO4, reducing agent and flux in the copper-containing sludge, and the sulfur element in the copper-containing sludge can promote the enrichment of Cu, Ni, Sn and the like in the copper slag and the copper-containing sludge into matte, so that the produced matte can be used in the main process of copper smelting, and the copper content in the obtained tailings can be reduced to below 0.5wt%, which can be used as a raw material for building materials. The obtained smoke is rich in lead, zinc and tin, which is conducive to subsequent recycling. Therefore, the method makes full use of the complementarity of the components of copper-containing sludge and copper slag, significantly reduces the use of flux and reducing agent, eliminates the sulfiding agent, significantly improves the depletion effect of copper slag, and realizes the resource recycling of various metals such as copper, nickel, lead, zinc, tin, etc. in copper-containing sludge and copper slag. The grade of the obtained matte is 40-60%, the copper recovery rate exceeds 96%, and the contents of copper, nickel, lead, zinc and tin in the tailings are less than 0.5wt%, 0.1wt%, 0.1wt%, 0.6wt% and 0.3wt%, respectively.

[0057] According to an embodiment of the present invention, referring to Figure 2 In order to recover the heat of high-temperature flue gas, promote the thermal energy utilization rate of the process, and reduce the energy consumption of drying copper-containing sludge, the above-mentioned method for treating copper-containing sludge further includes: using high-temperature flue gas to dry copper-containing sludge.

[0058] According to an embodiment of the present invention, referring to Figure 3 , the above method for treating copper-containing sludge further comprises:

[0059] S300: Collect dust from flue gas

[0060] In this step, the flue gas is subjected to dust collection treatment to obtain dust containing lead, zinc and tin. The inventors have found that the high-temperature flue gas obtained by smelting is rich in lead, zinc and tin. The high-temperature flue gas can be subjected to waste heat recovery and dust collection treatment to obtain dust with lead, zinc and tin contents greater than 5wt%, 30wt% and 20wt%, respectively. The dust can be used for lead, zinc and tin smelting, avoiding waste of resources and increasing profits.

[0061] In another aspect of the present invention, the present invention provides a system suitable for the above-mentioned method for treating copper-containing sludge, wherein CaO / SiO2>3, Fe / CaO<0.67 in the copper-containing sludge, that is, the copper-containing sludge described in the present application is high-calcium, low-silicon, low-iron type copper-containing sludge, and the Cu, Fe, Ca, S, and C in the copper-containing sludge are mainly in the form of sulfate (CuSO4), ferrous silicate (Fe2SiO4), calcium sulfate (CaSO4), sulfate (SO4 2- ), organic matter (C x H y Oz ) form. According to an embodiment of the present invention, reference Figure 4 The system includes: a drying device 100 and a smelting device 200.

[0062] According to an embodiment of the present invention, the drying device 100 has a copper-containing sludge inlet 101, a dried copper-containing sludge outlet 102 and a flue gas outlet 103, and is suitable for drying the copper-containing sludge to obtain dried copper-containing sludge and flue gas. It should be noted that the specific type of the drying device is not particularly limited, such as at least one of a rotary kiln and a tunnel kiln. Further, before drying, the copper-containing sludge can be pre-treated, such as performing filter pressing, drying and other processes to preliminarily remove the moisture in the copper-containing sludge. Further, the moisture content of the copper-containing sludge used for drying is not particularly limited, and those skilled in the art can select it according to actual needs, such as about 30wt%. As a result, it is beneficial to save energy consumption during drying treatment, and the energy consumption of pre-treatment is not too high, which is beneficial to reduce overall energy consumption. Further, the temperature of the drying treatment is not particularly limited, and those skilled in the art can select it according to actual needs, such as 600°C.

[0063] According to one embodiment of the present invention, the content of each component in the copper-containing sludge is not particularly limited, such as the content of TFe can be 2-10wt%, the content of CaO can be 15-30wt%, the content of SiO2 can be 0-5wt%, the content of Al2O3 can be 0-3wt%, the content of Cu can be greater than 10wt%, the content of Ni can be 0-0.5wt%, the content of Sn can be 0-1wt%, the content of S can be greater than 10wt%, and the content of C can be 2-10wt%, calculated on a dry basis of the copper-containing sludge.

[0064] According to an embodiment of the present invention, the smelting device 200 has a dried copper-containing sludge inlet 201, a copper slag inlet 202, a flux inlet 203, a reducing agent inlet 204, a matte outlet 205, a tailings outlet 206 and a high-temperature flue gas outlet 207. The dried copper-containing sludge inlet 201 is connected to the dried copper-containing sludge outlet 102 and is suitable for smelting the dried copper-containing sludge with copper slag, flux and reducing agent to obtain matte, tailings and high-temperature flue gas. The inventors found that during the smelting process, FeO and SiO2 in the copper slag can form a FeO-SiO2-CaO ternary slag system under the joint action of CaSO4, reducing agent and flux in the copper-containing sludge, and the sulfur element in the copper-containing sludge can promote the enrichment of Cu, Ni, Sn and the like in the copper slag and the copper-containing sludge into matte, so that the produced matte can be used in the main process of copper smelting, and the copper content in the obtained tailings can be reduced to below 0.5wt%, which can be used as a raw material for building materials. The obtained smoke is rich in lead, zinc and tin, which is conducive to subsequent recycling. That is, the smelting fully utilizes the complementarity of the components of copper-containing sludge and copper slag, significantly reduces the use of flux and reducing agent, and eliminates the sulfiding agent, significantly improves the depletion effect of copper slag, and realizes the resource recycling of copper, nickel, lead, zinc, tin and other metals in copper-containing sludge and copper slag. The grade of the obtained matte is 40-60%, the copper recovery rate exceeds 96%, and the contents of copper, nickel, lead, zinc and tin in the tailings are less than 0.5wt%, 0.1wt%, 0.1wt%, 0.6wt% and 0.3wt%, respectively. It should be noted that the specific type of the smelting device is not particularly limited, such as a depletion electric furnace. The depletion electric furnace equipment occupies a small area and has high processing efficiency.

[0065] Furthermore, in order to recover the heat of high-temperature flue gas, improve the thermal energy utilization rate of the process, and reduce the energy consumption of drying copper-containing sludge, refer to Figure 5 and Figure 6 The high-temperature flue gas outlet 207 can be connected to the drying device 100 .

[0066] According to one embodiment of the present invention, the mass ratio of copper-containing sludge to copper slag, flux and reducing agent is not particularly limited, and those skilled in the art can select according to actual needs. For example, the mass ratio of copper-containing sludge (on a dry basis) to copper slag, flux and reducing agent can be 100:10-50:2-10:5-10, specifically, it can be 100:10 / 20 / 30 / 40 / 50:2 / 4 / 6 / 8 / 10:5 / 6 / 7 / 8 / 9 / 10, or the mass ratio of copper-containing sludge (on a dry basis) to copper slag, iron tailings and reducing agent can be 100:10-50:5-30:5-10, specifically, it can be 100:10 / 20 / 30 / 40 / 50:5 / 10 / 15 / 20 / 25 / 30:5 / 6 / 7 / 8 / 9 / 10. Furthermore, the sum of the mass of the flux and the reducing agent may not be greater than 15% of the sum of the mass of the copper-containing sludge and the copper slag, and the copper-containing sludge is calculated on a wet basis. The inventors found that because the components in the copper-containing sludge and the copper slag are complementary, the amount of flux and reducing agent used is significantly reduced, avoiding the problem of solid waste volume increase caused by a large amount of flux ratio, and under the above-mentioned flux usage, the tailings slag type can also be optimized to reduce the copper content in the tailings. Specifically, the amount of flux and reducing agent used can be selected and added according to the content of each component in the copper-containing sludge and the copper slag to promote the recovery of valuable metal elements.

[0067] According to another embodiment of the present invention, the copper slag can be bottom-blown copper smelting slag to achieve the recycling of solid waste, and the Fe in the copper slag mainly exists in the form of FeO and Fe3O4, and the Cu mainly exists in the form of Cu2S and metal Cu. Further, the content of each component in the copper slag is not particularly limited, such as the content of TFe in the copper slag can be 35-45wt%, the content of CaO can be 0-5wt%, the content of SiO2 can be 20-30wt%, the content of MgO can be 0-3wt%, the content of Al2O3 can be 0-5wt%, the content of Cu can be 1-5wt%, the content of Pb can be 0-1wt%, the content of Zn can be 0-5wt%, and the content of S can be 1-3wt%. The copper slag is smelted together with the dried copper-containing sludge. The components in the copper slag can complement the components in the copper-containing sludge to form a FeO-SiO2-CaO ternary slag system. At the same time, it can also promote the enrichment of Cu, Ni, Sn and the like in the copper slag and the copper-containing sludge into matte, so that the copper content in the obtained tailings can be reduced to below 0.5wt%, and the obtained smoke is rich in lead, zinc and tin.

[0068] According to another embodiment of the present invention, the specific types of reducing agent and flux are not particularly limited. For example, the reducing agent can be selected from at least one of coal and coke, and the flux can be silica. The inventors found that the reducing agent can promote the reduction of calcium sulfate to CaS. When the reducing agent is present during the smelting process, Fe2O3 in the copper slag can react with CaS, 2CaS+Fe2O3+C=2CaO+2FeS+CO, and the produced FeS enters the matte phase. CaO combines with SiO2 in the flux or iron tailings to form calcium silicate, which can adjust the basicity of the slag and improve the slag melting performance. Further, the content of each component in the iron tailings is not particularly limited. For example, the content of TFe can be 10-20wt%, the content of CaO can be 1-5wt%, the content of SiO2 can be 50-75wt%, the content of MgO can be 1-5wt%, and the content of Al2O3 can be 1-10wt%. In the embodiments of the present invention, iron tailings are used instead of flux. The iron tailings itself is a solid waste, in which SiO2 can replace silica flux, and iron can replace the iron element in copper slag. The use of iron tailings instead of flux can not only provide a new treatment method for iron tailings solid waste, but also help to adjust the slag composition.

[0069] According to another embodiment of the present invention, the method for treating copper-containing sludge of the present application is adopted, and the ratio of raw materials is controlled so that CaO / SiO2=0.7-1.1, Fe / SiO2=0.5-1.2, Fe 3+ / Fe 2+ =0.09-0.11. The inventors found that within this composition range, the slag has good properties, mainly in that the slag has a lower melting point and a lower viscosity, which can reduce the smelting temperature, is conducive to the separation of the slag and the matte, and the dissolved copper content in the slag is low.

[0070] According to another embodiment of the present invention, the temperature of the smelting process can be 1250-1450°C. Specifically, during the smelting process, the temperature of the high-temperature flue gas outlet can be controlled in a higher range, such as 1250-1450°C, to promote the volatilization of lead, zinc and tin, while the composition of the matte and tailings near the matte and tailings outlet tends to be stable, and the temperature can be controlled in a lower range, such as 1250-1300°C. For example, when the smelting device is a depletion furnace, the high-temperature flue gas outlet and the dried copper-containing sludge inlet, copper slag inlet, flux inlet and reducing agent inlet are all located in the charging area of ​​the depletion furnace, while the matte outlet and tailings outlet are located at the discharge end of the depletion furnace. At the same time, the depletion furnace adopts electrode supplementary heating, so that it is possible to implement temperature control in the depletion furnace, and the recovery rate of valuable metals can be improved by temperature control, the smelting effect is improved and the smelting energy consumption is reduced.

[0071] According to the system for treating copper-containing sludge in an embodiment of the present invention, by using copper-containing sludge in combination with copper slag, and supplemented with flux and reducing agent, FeO and SiO2 in the copper slag can form a FeO-SiO2-CaO ternary slag system under the joint action of CaSO4, reducing agent and flux in the copper-containing sludge, and the sulfur element in the copper-containing sludge can promote the enrichment of Cu, Ni, Sn and the like in the copper slag and the copper-containing sludge into matte, so that the produced matte can be used in the main process of copper smelting, and the copper content in the obtained tailings can be reduced to below 0.5wt%, which can be used as a raw material for building materials, and the obtained smoke is rich in lead, zinc and tin, which is conducive to subsequent recycling. Therefore, the system makes full use of the complementarity of the components of copper-containing sludge and copper slag, significantly reduces the use of flux and reducing agent, saves sulfiding agent, significantly improves the depletion effect of copper slag, and realizes the resource recycling of copper, nickel, lead, zinc, tin and other metals in copper-containing sludge and copper slag. The grade of the obtained matte is 40-60%, the copper recovery rate exceeds 96%, and the contents of copper, nickel, lead, zinc and tin in the tailings are less than 0.5wt%, 0.1wt%, 0.1wt%, 0.6wt% and 0.3wt%, respectively. Furthermore, the system only combines the drying device with the smelting device to treat the copper-containing sludge, which significantly reduces the equipment investment and operation costs.

[0072] According to an embodiment of the present invention, referring to Figure 7 The above-mentioned system for treating copper-containing sludge further includes: a dust collecting device 300.

[0073] According to an embodiment of the present invention, the dust collecting device 300 has a flue gas inlet 301 and a flue gas outlet 302 containing lead, zinc and tin. The flue gas inlet 301 is connected to the flue gas outlet 103 and is suitable for collecting dust from the flue gas to obtain flue gas containing lead, zinc and tin. The inventors have found that the high-temperature flue gas obtained by smelting can obtain flue gas with lead, zinc and tin contents greater than 5wt%, 30wt% and 20wt% respectively after waste heat recovery and dust collection. The flue gas can be used for lead, zinc and tin smelting, avoiding waste of resources and increasing profits. It should be noted that the specific type of the dust collecting device is not particularly limited, such as a multi-stage dust removal device. Conventional dry dust removal devices are usually used, generally multiple dust removal devices are used in combination, a cyclone dust collector is used for coarse dust removal, and an electrostatic precipitator is used in the later stage.

[0074] It should be noted that the characteristics and advantages of the above-mentioned method for treating copper-containing sludge are also applicable to the system for treating copper-containing sludge, which will not be described in detail.

[0075] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0076] The raw materials used in the examples of this application are:

[0077] The moisture content of copper-containing sludge is 30%, and the dry basis components are 6.39wt% TFe, 6.61wt% FeO, 0.12wt% MgO, 19.88wt% CaO, 1.87wt% SiO2, 1.28wt% Al2O3, 15.18wt% Cu, 0.2wt% Ni, 0.5wt% Sn, 15.17wt% S and 4.85wt% C.

[0078] The copper slag is bottom-blown smelting furnace slag, in which the content of TFe is 44.57wt%, the content of FeO is 31.99wt%, the content of CaO is 3.29wt%, the content of SiO2 is 23.82wt%, the content of MgO is 1.42wt%, the content of Al2O3 is 2.29wt%, the content of Cu is 4.25wt%, the content of Pb is 0.41wt%, the content of Zn is 2.44wt% and the content of S is 1.46wt%.

[0079] The content of TFe in the iron tailings is 12.18wt%, the content of CaO is 4.83wt%, the content of SiO2 is 73.29wt%, the content of MgO is 3.24wt%, and the content of Al2O3 is 6.12wt%.

[0080] Example 1

[0081] The copper-containing sludge with a moisture content of 30% is dried at 600°C using a rotary kiln. After the hot material is dried, the copper-containing sludge is continuously fed into the lean electric furnace molten pool, and 30% of the total weight of the copper-containing sludge (on a dry basis) is added with copper slag, 10% of silica and 8% of crushed coal (the total amount of flux silica and reducing agent crushed coal added is 10.41% of the total mass of the treated solid waste copper-containing sludge and copper slag, and the copper-containing sludge is calculated on a wet basis, that is, the proportion of flux and reducing agent crushed coal to the total mass of the solid waste is (10% (flux) + 8% (reducing agent crushed coal)) / (100% (copper-containing sludge dry basis) ÷ 70% + 30% (copper slag) )=10.41%), the temperature of the charging point in the depleted electric furnace is controlled to be 1250-1450℃ by electrode heating, and the slag temperature is in the range of 1250~1350℃, to obtain matte, tailings and high-temperature flue gas, the obtained matte can be returned to the blowing furnace, the tailings are general solid waste and can be used as raw materials for building materials, the high-temperature flue gas is sent to the rotary kiln to dry the copper-containing sludge, the flue gas obtained by the rotary kiln is subjected to dust collection treatment, and smoke containing lead, zinc and tin is obtained, and the contents of lead, zinc and tin in the smoke are 8.53wt% (greater than 5%), 43.05wt% (greater than 30%) and 31.75wt% (greater than 20%), respectively.

[0082] Treatment results: 100,000 tons of copper-containing sludge (dry basis) and 30,000 tons of bottom-blown smelting slag are treated annually, producing 37,000 tons of copper matte (matte grade 44%), 55,000 tons of tailings (the tailings contain 0.28wt% copper, 0.3wt% zinc, 0.15wt% tin, and the content of nickel and lead is less than 0.1wt%, and the tailings contain CaO / SiO2=1.09, Fe / SiO2=0.76, Fe 3+ / Fe 2+ =0.1. ), the copper recovery rate of the whole process is 98.94%.

[0083] Example 2

[0084] The copper-containing sludge with a moisture content of 30% is dried at 600° C. The obtained hot material is dried and the copper-containing sludge is continuously fed into the depleted electric furnace molten pool, and 15% of the total weight of the copper-containing sludge (on a dry basis), 25% of the iron tailings and 10% of the crushed coal are added (the total amount of the reducing agent crushed coal added is 5.47% of the total weight of the treated solid waste copper-containing sludge, copper slag and iron tailings, and the copper-containing sludge is calculated on a wet basis, that is, the proportion of the reducing agent crushed coal to the total weight of the solid waste is 10% (reducing agent crushed coal) / (100% (copper-containing sludge dry basis) ÷ 70% + 15% (copper slag) + 25% (iron tailings)) = 5.47%), the temperature of the charging point in the depleted electric furnace is controlled to be 1250-1450°C by electrode heating, and the slag temperature is in the range of 1250-1350°C, to obtain matte, tailings and high-temperature flue gas, the obtained matte can be returned to the blowing furnace, the tailings are general solid waste and can be used as raw materials for building materials, the high-temperature flue gas is sent to the rotary kiln to dry the copper-containing sludge, the flue gas obtained by the rotary kiln is subjected to dust collection treatment, and smoke containing lead, zinc and tin is obtained, the contents of lead, zinc and tin in the smoke are 6.29wt% (greater than 5%), 31.89wt% (greater than 30%) and 45.15wt% (greater than 20%) respectively.

[0085] Treatment results: 100,000 tons of copper-containing sludge (dry basis), 15,000 tons of bottom-blown smelting slag, and 25,000 tons of iron tailings are treated annually, producing 26,000 tons of copper matte (matte grade 59%), 65,000 tons of tailings (the tailings contain 0.25wt% copper, 0.2wt% zinc, 0.25wt% tin, and the content of nickel and lead is less than 0.1wt%, and the tailings contain CaO / SiO2=1.00, Fe / SiO2=0.68, Fe 3+ / Fe 2+ =0.1. ), the copper recovery rate of the whole process is 96.98%.

[0086] Example 3

[0087] The copper-containing sludge with a moisture content of 30% is dried at 600°C using a rotary kiln. After the hot material is dried, the copper-containing sludge is continuously fed into the lean electric furnace molten pool, and 45% of the total weight of the copper-containing sludge (on a dry basis), 10% of silica and 5% of crushed coal are added (the total amount of flux silica and reducing agent crushed coal added is 7.98% of the total mass of the treated solid waste copper-containing sludge and copper slag, and the copper-containing sludge is calculated on a wet basis, that is, the proportion of flux and reducing agent crushed coal to the total mass of the solid waste is (10% (flux) + 5% (reducing agent crushed coal)) / (100% (copper-containing sludge dry basis) ÷ 70% + 45% (copper slag)) =7.98%), the temperature of the charging point in the depleted electric furnace is controlled to be 1250-1450°C by electrode heating, and the slag temperature is in the range of 1250-1350°C, to obtain matte, tailings and high-temperature flue gas, the obtained matte can be returned to the blowing furnace, the tailings are general solid waste and can be used as raw materials for building materials, the high-temperature flue gas is sent to the rotary kiln to dry the copper-containing sludge, the flue gas obtained by the rotary kiln is subjected to dust collection treatment, and smoke containing lead, zinc and tin is obtained, and the contents of lead, zinc and tin in the smoke are 12.84wt% (greater than 5%), 49.79wt% (greater than 30%) and 20.70wt% (greater than 20%), respectively.

[0088] Treatment results: 100,000 tons of copper-containing sludge (dry basis) and 45,000 tons of bottom-blown smelting slag are treated annually, producing 27,500 tons of copper matte (matte grade 60%), 86,000 tons of tailings (the tailings contain 0.4wt% copper, 0.6wt% zinc, 0.3wt% tin, and the content of nickel and lead is less than 0.1wt%, and the tailings contain CaO / SiO2=0.72, Fe / SiO2=1.17, Fe 3+ / Fe 2+ =0.1. ), the copper recovery rate of the whole process is 96.53%.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0090] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for treating copper-containing sludge, wherein CaO / SiO2>3, Fe / CaO<0.67, characterized in that: include: The copper-containing sludge is dried to obtain dried copper-containing sludge and flue gas, wherein the copper-containing sludge has a TFe content of 2-10wt%, a CaO content of 15-30wt%, a SiO2 content of 0-5wt%, and a S content of more than 10wt%, based on the dry basis of the copper-containing sludge; The dried copper-containing sludge, copper slag, flux or iron tailings, and reducing agent are smelted to obtain matte, tailings, and high-temperature flue gas, wherein the content of TFe in the copper slag is 35-45wt%, the content of CaO is 0-5wt%, the content of SiO2 is 20-30wt%, the content of MgO is 0-3wt%, the content of Al2O3 is 0-5wt%, the content of Cu is 1-5wt%, the content of Pb is 0-1wt%, the content of Zn is 0-5wt%, and the content of S is 1-3wt%; the mass ratio of the copper-containing sludge to the copper slag, flux, and reducing agent is 100:10-50:2-10:5-10, or the mass ratio of the copper-containing sludge to the copper slag, iron tailings, and reducing agent is 100:10-50:5-30:5-10, calculated on a dry basis of the copper-containing sludge.

2. The method according to claim 1, characterized in that The Al2O3 content in the copper-containing sludge is 0-3wt%, the Cu content is greater than 10wt%, the Ni content is 0-0.5wt%, the Sn content is 0-1wt%, and the C content is 2-10wt%, calculated on a dry basis of the copper-containing sludge.

3. The method according to claim 1 or 2, characterized in that: The sum of the masses of the flux and the reducing agent is not greater than 15% of the sum of the masses of the copper-containing sludge and the copper slag, and the mass of the copper-containing sludge is calculated as wet material; And / or, the copper slag is bottom-blown copper smelting slag; And / or, the reducing agent is selected from at least one of coal and coke; And / or, the flux is silica; And / or, the iron tailings contain 10-20wt% TFe, 1-5wt% CaO, 50-75wt% SiO2, 1-5wt% MgO and 1-10wt% Al2O3; And / or, the tailings contain CaO / SiO2=0.7-1.1, Fe / SiO2=0.5-1.2, Fe 3+ / Fe 2+ =0.09-0.

11.

4. The method according to claim 1, characterized in that The temperature of the smelting treatment is 1250-1450°C.

5. The method according to claim 1, characterized in that Further including: The high-temperature flue gas is used to dry the copper-containing sludge.

6. The method according to claim 5, characterized in that Further including: The flue gas is subjected to dust collection treatment to obtain the flue dust containing lead, zinc and tin.

7. A system suitable for the method for treating copper-containing sludge according to any one of claims 1 to 6, characterized in that: include: A drying device, the drying device having a copper-containing sludge inlet, a dried copper-containing sludge outlet and a flue gas outlet, the drying device being selected from at least one of a rotary kiln and a tunnel kiln; A smelting device, wherein the smelting device has an inlet for dried copper-containing sludge, a copper slag inlet, a flux or iron tailings inlet, a reducing agent inlet, a matte outlet, a tailings outlet and a high-temperature flue gas outlet, wherein the inlet for dried copper-containing sludge is connected to the outlet for dried copper-containing sludge, wherein the high-temperature flue gas outlet is connected to the drying device, and the smelting device is a depletion electric furnace; A dust collecting device is provided, wherein the dust collecting device has a smoke inlet and a smoke outlet containing lead, zinc and tin, and the smoke inlet is connected to the smoke outlet.

8. The system according to claim 7, characterized in that The dust collecting device is a multi-stage dust removal device.

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