Method for comprehensively recovering valuable metal through electric heating flash continuous reduction smelting

Abstract

The invention discloses a method for comprehensively recovering valuable metal through electric heating flash continuous reduction smelting, and belongs to the technical field of metal smelting. The characteristics of fine particle size and good activity of dust are fully utilized, the dust is mixed with coke powder, compressed carbon monoxide gas is sprayed into the electric heating flash continuous reduction smelting furnace, metal oxide particles are rapidly and continuously reduced under the conditions of high temperature and strong reduction atmosphere, liquid lead and mixed flue gas containing zinc, lead and carbon monoxide are produced, and the production efficiency is improved. Components such as silicon and calcium in the smoke dust are molten and enter the slag. The reduction reaction speed is high, the efficiency is high, and the productivity of equipment of the same specification is increased by 50%; zinc, lead, copper, tin, antimony and other valuable metals are simultaneously recovered in one smelting process; gas generated by the reaction is high-content carbon monoxide gas and is used as fuel, and no waste gas is discharged; the slag is common solid waste and can be used as a building material.

Description

Technical Field

[0001] The invention relates to the technical field of metal smelting, and in particular to a method for comprehensive recovery of valuable metals by electric thermal flash continuous reduction smelting. Background Art

[0002] At present, the pyrometallurgical lead smelting generally adopts the oxidation smelting-reduction smelting-fuming furnace depletion smelting process. During the depletion process of the lead smelting reduction slag in the fuming furnace, a large amount of dust mainly containing zinc and lead oxides is produced, which needs further treatment.

[0003] Therefore, it is a technical problem that technicians in this field urgently need to solve to provide a method for efficiently treating zinc and lead oxide-containing smoke dust by using a jet flash electrothermal continuous reduction process to directly produce crude zinc and crude lead products, while comprehensively recovering other valuable metal-rich products to produce high calorific value coal gas for recycling as fuel. Summary of the invention

[0004] In view of this, the present invention provides a method for comprehensive recovery of valuable metals by electric thermal flash continuous reduction smelting.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A method for comprehensive recovery of valuable metals by electrothermal flash continuous reduction smelting comprises the following steps:

[0007] (1) Using compressed carbon monoxide gas, a powder containing multi-metal oxides is mixed with coke powder and sprayed into an electric heating flash continuous reduction furnace, and silica and calcium oxide are added at the same time until the slag basicity is 0.8-1.2, and then coke particles required to completely reduce the iron in the reduction slag are added, and the reaction temperature is controlled to be 1300-1350° C. to reduce the multi-metal oxide powder sprayed into the furnace, thereby producing zinc-lead furnace gas, lead liquid and molten slag, and the metal oxides that have not been reduced in the molten slag are further reduced with coke particles to produce metals;

[0008] (2) condensing the zinc-lead furnace gas in a condenser to obtain a zinc-lead mixed melt, and after dust removal, 10-15% of the carbon monoxide gas in the zinc-lead furnace gas is pressurized as a gas for injection into the furnace for zinc oxide lead powder, and the remaining carbon monoxide is used as fuel;

[0009] (3) The obtained lead liquid is released every 24 to 48 hours and the ingots are sold as products;

[0010] (4) The mixed melt of zinc and lead is separated by smelting at 450-500°C to produce crude zinc and crude lead. The liquid crude zinc is sent to a distillation tower for refining to produce refined zinc, and the crude lead is cast into ingots for sale.

[0011] Furthermore, the compressed carbon monoxide gas has a concentration of 95-98%, a pressure of 0.06-0.08 MPa, and a flow rate of 100-700 Nm3 / h.

[0012] Furthermore, the feeding amount of the powder containing multi-metal oxides is 3 to 30 t / h;

[0013] The amount of coke powder added is calculated based on the contents of zinc, lead, copper, tin and antimony in the charge.

[0014] The amount of coke powder added is based on the ability to completely treat metals such as zinc, lead, and copper in the reduced material.

[0015] The amount of coke added is calculated based on the amount of iron that needs to be reduced in the slag.

[0016] The added amounts of silica and calcium oxide are calculated based on the contents of iron, calcium oxide and silicon dioxide in the charge.

[0017] Furthermore, the powder containing multi-metal oxides is composed of the following elements: 45-70% zinc, 1-15% lead, 0.3-5% copper, 0.1-3% tin, 0.2-2% antimony, 0.3-2% iron, 0.3-2% sulfur, 1-3% calcium, 1-3% silicon, and the balance is oxygen;

[0018] The particle size of the powder containing multiple metal oxides is less than 80 meshes.

[0019] Furthermore, the particle size of the coke powder is less than 0.3 mm, and the particle size of the coke particles is 3-30 mm;

[0020] Fixed carbon in coke powder>82%, volatile matter≤2%, ash≤15%, sulfur≤0.7%;

[0021] Fixed carbon in coke particles>82%, volatile matter≤2%, ash≤15%, sulfur≤0.7%;

[0022] Furthermore, the electric thermal flash continuous reduction furnace is heated by AC or DC electricity through electrodes, with a power of 4000-25000KVA.

[0023] Furthermore, in step (2), 10-15% of the carbon monoxide gas after dust removal is pressurized and used as injection gas for zinc oxide lead powder into the furnace, and 85-90% is used as fuel.

[0024] The working principle and working process of the present invention are as follows:

[0025] The powder containing multi-metal oxides is mixed with coke powder and injected into the reduction furnace through compressed carbon monoxide. The main chemical reactions that occur are:

[0026] MeO (S) +C (S)=Me (l、g) +CO (g)

[0027] MeO (S) +CO (S) =Me (l、g) +CO 2(g)

[0028] CO 2(S) +C (S) =2CO (g)

[0029] The materials added into the electric heating flash continuous reduction smelting furnace are reduced to zinc, lead, copper and other valuable metals at a temperature of 1300-1350°C, and zinc and part of lead are volatilized.

[0030] The chemical reaction that occurs is:

[0031] PbO+CO=Pb+CO 2 ↑

[0032] PbO+C=Pb+CO↑

[0033] ZnO+C=Zn↑+CO↑

[0034] ZnO+CO=Zn↑+CO 2 ↑

[0035] CuO+C=Cu+CO↑

[0036] CuO+CO=Cu+CO 2 ↑

[0037] CO 2 +C=2CO↑

[0038] The arc heat generated by the graphite electrode and the Joule heat generated by the slag resistance heat the molten pool together. Under the temperature condition of 1300-1350℃, the materials in the furnace are completely melted into slag to maintain the heat required for the reduction reaction. The carbon content of the coke added is 1.0-1.2 times the theoretical amount of reduced zinc, lead, copper, tin, antimony and iron.

[0039] In the scheme of the present invention, the zinc recovery rate is greater than 97%, the lead recovery rate is greater than 98%, and the copper recovery rate is greater than 85%;

[0040] The operation mode of the electric heating flash continuous reduction smelting furnace in the present invention can continuously add materials and continuously discharge slag, and the slag contains ≤2% zinc and ≤0.05% lead. The slag of the electric heating flash continuous reduction smelting furnace can be further depleted according to the content of valuable metals such as copper, indium, and germanium, so as to improve the recovery rate of rare metals such as germanium and indium. In the present invention, the recovery rate of indium is greater than 85%, and the recovery rate of germanium is greater than 90%.

[0041] The beneficial effects of the present invention are as follows: the present invention makes full use of the fine particle size and good activity of dust, mixes it with coke powder, and uses compressed carbon monoxide gas to spray into an electric flash continuous reduction smelting furnace, so that metal oxide particles are rapidly and continuously reduced under high temperature and strong reducing atmosphere conditions, and liquid lead and mixed flue gas containing zinc, lead and carbon monoxide are produced, and silicon, calcium and other components in the flue dust are melted into the slag. Liquid lead and slag are released regularly, and the furnace gas condenses zinc and lead into a mixed melt through a condenser, and zinc and lead are separated by melting to produce crude zinc and crude lead respectively. After the furnace gas is further cooled and dusted, a small part is pressurized as flue gas injection gas, and most of it is recycled as high calorific value fuel. The present invention has a high reduction reaction speed and high efficiency, and the production capacity of equipment with the same specifications is increased by 50%; zinc, lead, copper, tin, antimony and other valuable metals are recovered simultaneously in one smelting process; the gas produced by the reaction is a high-content carbon monoxide gas, which is used as fuel without exhaust gas emission; the slag is a general solid waste and can be used as a building material. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Example 1

[0044] (1) The powder containing multi-metal oxides in this embodiment is composed of the following elements: 63% zinc, 9.3% lead, 0.2% copper, 0.2% tin, 0.56% iron, 0.89% sulfur, 0.5% calcium, 0.8% silicon, and the balance is oxygen;

[0045] Coke powder: particle size 0.02-0.3 mm, fixed carbon 84%, volatile matter 1.8%, ash 13.7%, sulfur 0.7%;

[0046] Use concentration 97.5%, h flow rate 133Nm 3 / h, compressed carbon monoxide gas with a pressure of 0.06MPa, spraying the powder containing multi-metal oxides and coke powder into the electric thermal flash continuous reduction furnace, the feeding amount of the powder containing multi-metal oxides is 4t / h, the proportion of coke powder is 0.632t / h, and at the same time, 0.112t / h of calcium oxide and 0.005t / h of coke particles are added. The power of the electric thermal flash continuous reduction furnace is 6300KVA, and the reaction temperature is controlled at 1350℃ through electrode heating to reduce the multi-metal oxide powder sprayed into the furnace, and produce zinc-lead furnace gas and lead liquid containing copper and tin; at the same time, calcium oxide and silicon dioxide in the multi-metal oxide powder are melted with other materials such as calcium oxide added to produce molten slag, and the metal oxides that have not been reduced in the molten slag are further reduced with coke particles to produce metals;

[0047] (2) The zinc-lead furnace gas is condensed in the condenser to obtain a zinc-lead mixed melt. The carbon monoxide gas in the zinc-lead furnace gas is 133Nm 3 / h pressurized to 0.6MPa as the injection gas for zinc oxide lead powder into the furnace, and the remaining 991Nm 3 / h used as fuel;

[0048] (3) releasing 5.3 tons of the resulting lead liquid every 24 hours, containing 95% lead, 1.2% copper, and 3.44% tin, and the ingots are sold as products;

[0049] (4) The mixed zinc and lead melt is separated by smelting to produce 2.4 t / h of crude zinc, containing 98% zinc and 1.8% lead, and 0.135 t / h of crude lead, containing 98.8% lead and 0.75% zinc. The crude zinc and lead ingots are sold externally.

[0050] In this example, the zinc recovery rate is 97.5%, the lead recovery rate is 98%, the copper recovery rate is 85%, the slag contains 1.88% zinc, and the slag contains ≤0.05% lead.

[0051] Example 2

[0052] (1) The powder containing multi-metal oxides in this embodiment is composed of the following elements: 57% zinc, 11.5% lead, 0.05% copper, 0.2% tin, 0.8% iron, 0.96% sulfur, 0.4% calcium, 1.2% silicon, and the balance is oxygen;

[0053] Coke powder: particle size 0.02-0.3 mm, fixed carbon 85%, volatile matter 2%, ash 12.2%, sulfur 0.7%;

[0054] Coke particles: particle size 3-30mm, fixed carbon 85%, volatile matter 2%, ash 12.2%, sulfur 0.7%;

[0055] Use concentration 97%, h flow rate 100Nm 3 / h, compressed carbon monoxide gas with a pressure of 0.06MPa, spraying the powder containing multi-metal oxides and coke powder into the electric thermal flash continuous reduction furnace, the feeding amount of the powder containing multi-metal oxides is 3t / h, the proportion of coke powder is 0.412t / h, and at the same time, 0.23t / h of calcium oxide and 0.01t / h of coke particles are added. The power of the electric thermal flash continuous reduction furnace is 4000KVA, and the reaction temperature is controlled at 1350℃ through electrode heating to reduce the multi-metal oxide powder sprayed into the furnace, and produce zinc-lead furnace gas and lead liquid containing copper and tin; at the same time, the calcium oxide and silicon dioxide in the multi-metal oxide powder are melted with other materials such as the added calcium oxide to produce molten slag, and the metal oxides that have not been reduced in the molten slag are further reduced with coke particles to produce metals;

[0056] (2) The zinc-lead furnace gas is condensed in a condenser to obtain a zinc-lead mixed melt. The carbon monoxide gas in the zinc-lead furnace gas is dedusted to 100Nm 3 / h pressurized to 0.6MPa as the injection gas for zinc oxide lead powder into the furnace, and the remaining 654Nm 3 / h used as fuel;

[0057] (3) 10.14 tons of the resulting lead liquid is released every 48 hours, containing 95% lead, 0.57% copper, and 2.56% tin, and the ingots are sold as products;

[0058] (4) The mixed zinc and lead melt is separated by smelting to produce 1.63 t / h of crude zinc, containing 98% zinc and 1.75% lead, and 0.131 t / h of crude lead, containing 99% lead and 0.8% zinc. The crude zinc and lead ingots are sold externally.

[0059] In this example, the zinc recovery rate is 97.2%, the lead recovery rate is 98%, the copper recovery rate is 80%, the slag contains 1.78% zinc, and the slag contains ≤0.05% lead.

[0060] Example 3

[0061] (1) The powder containing multi-metal oxides in this embodiment is composed of the following elements: 51% zinc, 20.5% lead, 0.05% copper, 1.8% iron, 251g / t silver, 173g / t indium, 73g / t germanium, 1.1% sulfur, 1.75% calcium, 2.3% silicon, and the balance is oxygen;

[0062] Coke powder: particle size 0.02-0.3 mm, fixed carbon 85%, volatile matter 2%, ash 12.2%, sulfur 0.7%;

[0063] Coke particles: particle size 3-30mm, fixed carbon 85%, volatile matter 2%, ash 12.2%, sulfur 0.7%;

[0064] Use concentration 97%, h flow rate 180Nm 3 / h, compressed carbon monoxide gas with a pressure of 0.06MPa, spray the powder containing multi-metal oxides and coke powder into the electric thermal flash continuous reduction furnace, the feeding amount of the powder containing multi-metal oxides is 5t / h, the proportion of coke powder is 0.652t / h, and at the same time, 0.43t / h of calcium oxide and 0.02t / h of coke particles are added. The power of the electric thermal flash continuous reduction furnace is 9300KVA, and the reaction temperature is controlled at 1350℃ through electrode heating to reduce the multi-metal oxide powder sprayed into the furnace, and produce zinc-lead furnace gas and lead liquid containing copper and tin; at the same time, the calcium oxide and silicon dioxide in the multi-metal oxide powder are melted with other materials such as the added calcium oxide to produce molten slag, and the metal oxides that have not been reduced in the molten slag are further reduced with coke particles to produce metals;

[0065] (2) The zinc-lead furnace gas is condensed in a condenser to obtain a zinc-lead mixed melt. The carbon monoxide gas in the zinc-lead furnace gas is dedusted to 180 Nm 3 / h pressurized to 0.6MPa as the injection gas for zinc oxide lead powder into the furnace, and the remaining 1035Nm 3 / h used as fuel;

[0066] (3) 17.57 tons of the resulting lead liquid is released every 24 hours, containing 98% lead, 0.16% copper, and 1371 g / t silver, and the ingots are sold as products;

[0067] (4) The mixed zinc and lead melt is separated by smelting to produce 2.42 t / h of crude zinc, containing 98% zinc, 1.85% lead, 53 g / t silver, 303 g / t indium, and 128 g / t germanium. The crude lead is produced at 0.242 t / h, containing 99% lead and 0.85% zinc. The crude zinc and lead ingots are sold externally.

[0068] In this example, the zinc recovery rate is 97.3%, the lead recovery rate is 98%, the copper recovery rate is 80%, the indium recovery rate is greater than 85%, the germanium recovery rate is greater than 90%, and the silver recovery rate is 90%.

[0069] The slag is depleted in a depletion furnace, and the zinc content in the slag is 0.98%, and the lead content in the slag is ≤0.02%.

[0070] 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 comprehensive recovery of valuable metals by electrothermal flash continuous reduction smelting, characterized in that: The following steps are involved: (1) Using compressed carbon monoxide gas, a powder containing multi-metal oxides is mixed with coke powder and sprayed into an electric heating flash continuous reduction furnace, and silica and calcium oxide are added at the same time until the slag basicity is 0.8-1.2, and then coke particles required to completely reduce the iron in the reduction slag are added, and the reaction temperature is controlled to be 1300-1350° C. to reduce the multi-metal oxide powder sprayed into the furnace, thereby producing zinc-lead furnace gas, lead liquid and molten slag, and the metal oxides that have not been reduced in the molten slag are further reduced with coke particles to produce metals; (2) condensing the zinc-lead furnace gas in a condenser to obtain a zinc-lead mixed melt, and after dust removal, 10-15% of the carbon monoxide gas in the zinc-lead furnace gas is pressurized as a gas for injection into the furnace for zinc oxide lead powder, and the remaining carbon monoxide is used as fuel; (3) The obtained lead liquid is released every 24 to 48 hours and the ingots are sold as products; (4) The mixed melt of zinc and lead is separated by smelting at 450-500°C to produce crude zinc and crude lead. The liquid crude zinc is sent to a distillation tower for refining to produce refined zinc, and the crude lead is cast into ingots for sale.

2. According to claim 1, a method for comprehensive recovery of valuable metals by electric thermal flash continuous reduction smelting, characterized in that: The compressed carbon monoxide has a volume concentration of 95-98%, a pressure of 0.06-0.08 MPa, and a flow rate of 100-700 Nm3 / h.

3. The method for comprehensive recovery of valuable metals by electrothermal flash continuous reduction smelting according to claim 1, characterized in that: The feeding amount of the powder containing multi-metal oxides is 3-30 t / h; The amount of coke powder added is calculated based on the content of zinc, lead, copper, tin and antimony in the charge. The amount of coke added is calculated based on the amount of iron that needs to be reduced in the slag. The added amounts of silica and calcium oxide are calculated based on the contents of iron, calcium oxide and silicon dioxide in the charge.

4. The method for comprehensive recovery of valuable metals by electrothermal flash continuous reduction smelting according to claim 3, characterized in that: The powder containing multi-metal oxides is composed of the following elements: 45-70% zinc, 1-15% lead, 0.3-5% copper, 0.1-3% tin, 0.2-2% antimony, 0.3-2% iron, 0.3-2% sulfur, 1-3% calcium, 1-3% silicon, and the balance is oxygen; The particle size of the powder containing multiple metal oxides is less than 80 meshes.

5. The method for comprehensive recovery of valuable metals by electrothermal flash continuous reduction smelting according to claim 3, characterized in that: The particle size of the coke powder is less than 0.3 mm, and the particle size of the coke particles is 3-30 mm; Fixed carbon in coke powder>82%, volatile matter≤2%, ash≤15%, sulfur≤0.7%; The fixed carbon in the coke particles is greater than 82%, the volatile matter is ≤2%, the ash is ≤15%, and the sulfur is ≤0.7%.

6. The method for comprehensive recovery of valuable metals by electrothermal flash continuous reduction smelting according to claim 1, characterized in that: The electric heating flash continuous reduction furnace is heated by AC or DC electricity through electrodes, and the power is 4000-25000KVA.