A side-blown molten furnace body and a process for extracting heavy metals by high-temperature melting treatment of hazardous waste

Abstract

The present application relates to a kind of side-blown molten furnace body and the process for extracting heavy metal in hazardous waste high-temperature melting treatment, including main furnace body, auxiliary furnace body, the main furnace body includes exhaust area, secondary combustion zone, furnace body area, furnace belly area, hearth area, forehearth area, forehearth area is set in the side of hearth area, secondary combustion zone is equipped with burner and secondary air lance, furnace belly area is equipped with burner and rich-oxygen injection main gun, forehearth area is equipped with molten metal outlet, residue outlet, molten slag outlet from bottom to top at different heights;Auxiliary furnace body includes vice exhaust area, vice combustion zone, oxidation burn-out zone, vice exhaust area is communicated with exhaust area, vice combustion zone is equipped with burner and burn-out rich-oxygen lance, the molten slag outlet of forehearth area is communicated with oxidation burn-out zone.The present application uses rich-oxygen combustion support, material is heated to above melting point in high-temperature melting furnace, realizes the reduction separation of slag and heavy metal, and the molten slag separated is combusted again, realizes safe production and avoids secondary pollution.

Description

TECHNICAL FIELD

[0001] The present application relates to industrial furnace equipment, in particular to a side-blown molten furnace body and a process for extracting heavy metals by high-temperature melting treatment of hazardous waste. BACKGROUND

[0002] The treatment of hazardous waste containing heavy metals is a major problem in today's industrial production. In the prior art, landfill or plasma furnace high-temperature melting treatment is generally used. The use of landfill method has large land occupation, high cost and the possibility of secondary pollution. The use of plasma furnace to treat hazardous waste containing heavy metals can melt and vitrify the hazardous waste at high temperature to achieve harmlessness, but the equipment investment is very high, the power consumption is also very high, the spare parts consumption of the plasma gun is high, and the operation cost is high, which is economically difficult to bear for the treatment of general hazardous waste.

[0003] The patent document with application number 201810875985.0 discloses a process for cleaning and efficiently treating lead-containing waste slag. The invention uses an oxygen-enriched strengthening smelting process to further improve the heat generation and transfer process of the smelting furnace, strengthen the oxidation-reduction atmosphere in different stages, improve the sulfur dioxide concentration in the flue gas, combustion efficiency, and strengthen the oxidation-reduction process of the material, and improve the treatment efficiency. In particular, heavy oil combustion is introduced to quickly raise the temperature in the furnace, making the temperature and atmosphere easier to control. The invention uses a five-stage integrated new type smelting furnace to realize the integration of material preheating, sintering, smelting, and clarification layering, and better realizes the selective separation of heavy metals, valuable metals, and gangue, etc., realizes the clean and efficient treatment of hazardous waste, achieves the purpose of resource utilization, harmlessness, and comprehensive utilization, meets the relevant environmental protection requirements of the state, and has the advantages of short process, simple operation, low investment, and low cost. The smelting process of the invention uses negative pressure operation to prevent unorganized emission of gas, protect the environment, and ensure the occupational health of workers. The invention directly smelts to obtain crude lead, solving the problems of low efficiency, high energy consumption, and serious environmental pollution existing in conventional treatment processes. However, the smelting zone and the layering section of the invention are arranged in communication with each other, the layering section is easily affected by the upper smelting zone, causing stirring and difficulty in standing, which causes difficulty in separating the metal and the slag in the furnace. In addition, the temperature of the smelting zone of the invention can only reach 1150-1250℃, which can realize the smelting of lead, but it is difficult to realize the smelting of heavy metals with higher melting points.

[0004] In addition, during the separation of molten slag and metal, a small amount of unburned combustible material may remain in the upper layer of molten slag, which is easy to explode and cause secondary pollution accidents during the process of discharging the molten slag after separation. SUMMARY

[0005] The application aims to provide a side-blowing melting furnace body and a process for extracting heavy metals by high-temperature melting treatment of hazardous waste, which adopts oxygen-enriched combustion, heats the materials to above the melting point in the high-temperature melting furnace under the oxygen-enriched combustion, and realizes the melting reduction separation of slag and heavy metals by causing a high-temperature reducing atmosphere in the furnace belly area and the furnace hearth area if the hazardous waste contains recyclable heavy metals, and fully burns the small part of unburned combustibles remaining in the molten slag by re-combusting the separated molten slag, so as to realize safe production and avoid secondary pollution.

[0006] In order to achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0007] A side-blowing melting furnace body, comprising a main furnace body and an auxiliary furnace body, the main furnace body comprises a smoke exhaust area, a secondary combustion area, a furnace shaft area, a furnace belly area, a furnace hearth area and a furnace front area, the smoke exhaust area, the secondary combustion area, the furnace shaft area, the furnace belly area and the furnace hearth area are sequentially arranged from top to bottom, the furnace front area is arranged on the side of the furnace hearth area, and the downward inclined discharge is from the furnace hearth area to the furnace front area, the secondary combustion area is provided with a burner and a secondary air injection lance, the furnace belly area is provided with a burner and an oxygen-enriched injection main lance, and the furnace front area is provided with a molten metal outlet, a residue outlet and a molten slag outlet at different heights from bottom to top.

[0008] The auxiliary furnace body comprises a vice smoke exhaust area, a vice combustion area and an oxidation combustion area, the vice smoke exhaust area, the vice combustion area and the oxidation combustion area are sequentially arranged from top to bottom, the vice smoke exhaust area is communicated with the smoke exhaust area, the vice combustion area is provided with a burner and a combustion oxygen-enriched injection lance, the molten slag outlet of the furnace front area is communicated with the oxidation combustion area, a retaining wall is arranged between the lower part of the furnace front area and the oxidation combustion area, and the oxidation combustion area is provided with slag outlets at different heights.

[0009] The top of the smoke exhaust area is connected with a discharging device, and the side of the smoke exhaust area is provided with a smoke exhaust port.

[0010] The inner wall of the smoke exhaust area, the secondary combustion area, the furnace shaft area, the furnace hearth area and the furnace front area is a refractory material layer, and the outer wall of the refractory material layer is a water cooling jacket.

[0011] The inner wall of the furnace belly area is a refractory material layer, the outer wall is also a refractory material layer, and the two layers of refractory material layers are water cooling walls.

[0012] The inner wall of the vice combustion area is a refractory material layer, the outer wall is also a refractory material layer, and the two layers of refractory material layers are water cooling walls.

[0013] The smoke exhaust area is designed to be expanded in diameter compared with the secondary combustion area.

[0014] The secondary air injection lance is horizontally installed and is tangentially injected along the inner wall of the furnace body.

[0015] The bottom of the hearth zone and the bottom of the oxidizing combustion zone are provided with furnace bottom cooling pipes.

[0016] The process for extracting heavy metals by using a side-blown molten furnace body for hazardous waste high-temperature melting treatment comprises the following steps: material is introduced from the top of the smoke exhaust zone, heated by twice oxygen-rich combustion in the secondary combustion zone and the bosh zone, the local temperature of the hearth zone and the bosh zone can reach above 2000 DEG C, so that the material is rapidly melted, the temperature of the molten material in the hearth zone is above 1500 DEG C, the molten material flows to the front zone to realize the separation of slag and metal, the molten slag floating on the uppermost layer flows to the oxidizing combustion zone to burn off the residual combustible in the molten slag.

[0017] Compared with the prior art, the process has the following beneficial effects:

[0018] 1) The volume of the slag separated by the process is greatly reduced, only about 10%-20% of the original, and if landfill is used, the occupied area is only one fifth to one tenth of the original.

[0019] 2) The local temperature of the oxygen-rich spray and swirl zone in the hearth zone and the bosh zone can reach above 2000 DEG C, so that the material is rapidly melted, the temperature of the molten material in the hearth zone can reach above 1500 DEG C, the viscosity of the slag is reduced, the flowability of the slag is increased, the separation of slag and metal is facilitated, and the process is suitable for a wider range of heavy metal melting points.

[0020] 3) The process recovers heavy metals and realizes resource utilization.

[0021] 4) The hazardous waste high-temperature melting treatment process has good economic efficiency and is sustainable.

[0022] 5) The molten slag after treatment can be burned again, so that the small part of residual unburned combustible in the molten slag is fully burned, safe production is realized, and secondary pollution is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a schematic diagram of the overall structure of the present application.

[0024] Figure 2 is a top view of Figure 1 .

[0025] Fig. 1: 1 - material tank, 2 - discharger, 3 - distribution pipe, 4 - water-cooled wear-resistant distribution pipe, 5 - water-cooled jacket, 6 - refractory layer, 7 - secondary air lance, 8 - flue gas zone, 9 - secondary combustion zone, 10 - high-temperature industrial TV, 11 - optical pyrometer, 12 - water-cooled wall, 13 - main oxygen-enriched lance, 14 - fuel injection auxiliary lance, 15 - shaft zone, 16 - bosh zone, 17 - bottom cooling pipe, 18 - molten metal outlet, 19 - residue outlet, 20 - oxidation and burnout zone, 21 - temperature measuring thermocouple, 22 - flue gas outlet, 23 - explosion-proof valve, 24 - auxiliary flue gas zone, 25 - burnout oxygen-enriched lance, 26 - burnout fuel injection lance, 27 - hearth zone, 28 - front zone, 29 - retaining wall, 30 - upper residue outlet, 31 - lower residue outlet, 32 - connecting flue, 33 - auxiliary combustion zone. DETAILED DESCRIPTION

[0026] The specific embodiments of the present application will be further described below in conjunction with the accompanying drawings:

[0027] See Figure 1 , Figure 2 A side-blown smelting furnace body, comprising a main furnace body and an auxiliary furnace body, the main furnace body comprising a flue gas zone 8, a secondary combustion zone 9, a shaft zone 15, a bosh zone 16, a hearth zone 27, and a front zone 28, the flue gas zone 8, the secondary combustion zone 9, the shaft zone 15, the bosh zone 16, and the hearth zone 27 being arranged in sequence from top to bottom, the front zone 28 being arranged on the side of the hearth zone 27, the secondary combustion zone 9 being provided with a burner and a secondary air lance 7, the bosh zone 16 being provided with a burner and a main oxygen-enriched lance 13, and the front zone 28 being provided with a molten metal outlet 18, a residue outlet 19, and a molten slag outlet at different heights from bottom to top.

[0028] The auxiliary furnace body comprises an auxiliary flue gas zone 24, an auxiliary combustion zone 33, and an oxidation and burnout zone 20, the auxiliary flue gas zone 24, the auxiliary combustion zone 33, and the oxidation and burnout zone 20 being arranged in sequence from top to bottom, the auxiliary flue gas zone 24 being in communication with the flue gas zone 8, the auxiliary combustion zone 33 being provided with a burner and a burnout oxygen-enriched lance 25, the molten slag outlet of the front zone 28 being in communication with the oxidation and burnout zone 20, a retaining wall being arranged between the lower part of the front zone 28 and the oxidation and burnout zone 20, and the oxidation and burnout zone 20 being provided with residue outlets (an upper residue outlet 30 and a lower residue outlet 31) at different heights.

[0029] The top of the flue gas zone 8 is connected to a material distribution device, and the side of the flue gas zone 8 is provided with a flue gas outlet 22. The top of the auxiliary flue gas zone 24 is provided with an explosion-proof valve 23.

[0030] The inner walls of the flue gas zone 8, the secondary combustion zone 9, the shaft zone 15, the hearth zone 27, and the front zone 28 are refractory layers 6, and the outer walls of the refractory layers 6 are water-cooled jackets 5.

[0031] The inner wall of the bosh zone 16 is a layer of refractory material, and the outer wall is also a layer of refractory material, and the two layers of refractory material are separated by a water-cooled wall 12.

[0032] The inner wall of the bosh zone 16 is a layer of refractory material, and the outer wall is also a layer of refractory material, and the two layers of refractory material are separated by a water-cooled wall 12.

[0033] The exhaust zone 8 is designed to be larger in diameter than the secondary combustion zone 9. The expansion design of the exhaust zone 8 can reduce the emission of smoke.

[0034] The secondary air lance 7 is installed horizontally and blows tangentially along the inner wall of the furnace body.

[0035] The bottom of the furnace hearth zone 27 and the bottom of the oxidation and burnout zone 20 are both provided with a furnace bottom cooling pipe 17, which can be air-cooled or water-cooled.

[0036] The bosh zone 16 is provided with a copper or iron water-cooled wall 12, an oxygen-enriched blowing main lance 13 is used to blow oxygen-enriched, pure oxygen or compressed air into the burner, a fuel blowing secondary lance 14 is used to supply fuel gas, pulverized coal, powdered combustible material and other fuels to the burner, the number of oxygen-enriched blowing main lances 13 and fuel blowing secondary lances 14 is determined according to the size and output of the furnace, and they are inclined downward at a certain angle with the horizontal plane, under the action of oxygen-enriched air, oxidation and combustion reactions occur between the injected fuel and combustible materials in the furnace, which melts the hazardous waste, the water-cooled wall protects the furnace body from being eroded by high-temperature molten slag, and a layer of refractory material 6 is provided on the inner and outer sides of the water-cooled wall 12.

[0037] The bosh zone 16 is provided with a copper or iron water-cooled wall 12, an oxygen-enriched blowing main lance 13 is used to blow oxygen-enriched, pure oxygen or compressed air into the burner, a fuel blowing secondary lance 14 is used to supply fuel gas, pulverized coal, powdered combustible material and other fuels to the burner, the number of oxygen-enriched blowing main lances 13 and fuel blowing secondary lances 14 is determined according to the size and output of the furnace, and they are inclined downward at a certain angle with the horizontal plane, under the action of oxygen-enriched air, oxidation and combustion reactions occur between the injected fuel and combustible materials in the furnace, which melts the hazardous waste, the water-cooled wall protects the furnace body from being eroded by high-temperature molten slag, and a layer of refractory material 6 is provided on the inner and outer sides of the water-cooled wall 12.

[0038] The refractory material layer 6 is provided with temperature measuring thermocouples 21 at different positions and depths for detecting the temperature of each part, and the furnace hearth zone 27 is used to store molten slag and molten metal, which realizes the separation of slag and metal together with the furnace front zone 28 by using the difference in specific gravity.

[0039] The slag from the furnace front area 28 flows through the dam 29 into the auxiliary furnace body of the oxidation combustion zone 20, the auxiliary combustion zone 33 above the oxidation combustion zone 20 is provided with a burner and a combustion oxygen-enriched lance 25, and fuel is fed to the burner through the combustion fuel lance 26, and the slag in the oxidation combustion zone 20 is further burned to burn off the combustible substances remaining in the slag. The slag after the combustion treatment is discharged from the slag outlet and can be collected after glassification treatment. The glassification treatment can be: the slag is discharged into the slag pool through the discharge chute, the lower part of the discharge chute is provided with a high-pressure water (or high-pressure air) lance to quench the slag (or air cooling) to realize the granulation of the slag, and the granulated slag falls into the slag pool to complete the glassification process of the slag.

[0040] The high-temperature industrial television 10 and the optical pyrometer 11 are arranged in the furnace body area 15 to monitor the working conditions in the furnace and the working state of the water cooling jacket 5 and the refractory layer 6.

[0041] The burner of the secondary combustion zone 9 is provided with a secondary air lance 7 for blowing oxygen-enriched, pure oxygen or compressed air into the burner. The lance is horizontally installed and tangent to an imaginary circle in the furnace, and the gas flow injected into the furnace rotates tangentially in the furnace, which can enhance the mixing with the lower reducing flue gas and burn off the combustible substances such as CO, H2 and CH4 in the flue gas. The flue gas after incineration is sent to the rear flue gas treatment system through the exhaust port 22 for waste heat utilization, environmental protection treatment and standard emission.

[0042] The hazardous waste is first pretreated, such as: mixing, sieving, granulating (block making, granulation, ball pressing), drying, and then sent into the hopper 1 through the belt or elevator, and loaded into the melting furnace through the unloader 2, the discharge distribution pipe 3 and the water-cooled wear-resistant discharge pipe 4. If the melting method is used to extract metals from the hazardous waste, the oxygen-deficient combustion in the furnace hearth area 27, the furnace belly area 16 and the furnace body area 15 all creates a reducing atmosphere to create a reducing environment for metal or metal oxides, and realizes the reduction and separation of slag and heavy metals. The local temperature of the furnace hearth area 27 and the furnace belly area 16 can reach more than 2000°C, so that the material is quickly melted, and the temperature of the molten material in the furnace hearth area 27 is more than 1500°C, and the molten material flows to the furnace front area 28 to realize the separation of slag and metal.

[0043] The discharged metal ingot or further processing is not required to consider the reducing atmosphere in the entire furnace area if it is only hazardous waste melting and glassification treatment.

[0044] The process for extracting heavy metals by using side-blown molten furnace body for hazardous waste high-temperature melting treatment comprises the following steps: material enters from the top of the smoke exhaust area 8, is heated twice by oxygen-rich combustion in the secondary combustion area 9 and the bosh area 16, the local temperature of the hearth area 27 and the bosh area 16 can reach more than 2000 DEG C, so that the material is rapidly melted, the temperature of the molten material in the hearth area 27 is more than 1500 DEG C, the molten material flows to the front area 28 to realize the separation of slag and metal, and the molten slag floating on the uppermost layer flows to the oxidation and combustion area 20 to burn off the combustible residues in the molten slag.

Claims

1. A side-blown molten bath vessel, characterized by, The side-blown melting furnace body comprises a main furnace body and an auxiliary furnace body, the main furnace body comprises a flue gas discharging zone, a secondary combustion zone, a shaft zone, a belly zone, a hearth zone and a forehearth zone, the flue gas discharging zone, the secondary combustion zone, the shaft zone, the belly zone and the hearth zone are sequentially arranged from top to bottom, the forehearth zone is arranged on the side of the hearth zone, and the material is discharged downwardly from the hearth zone to the forehearth zone, the secondary combustion zone is provided with a burner and a secondary air injection lance, the belly zone is provided with a burner and an oxygen-enriched injection main lance, and the forehearth zone is provided with a molten metal outlet, a residue outlet and a molten slag outlet at different heights from bottom to top; The auxiliary furnace body comprises a secondary flue gas discharging zone, a secondary combustion zone and an oxidation and burn-out zone, the secondary flue gas discharging zone, the secondary combustion zone and the oxidation and burn-out zone are sequentially arranged from top to bottom, the secondary flue gas discharging zone is communicated with the flue gas discharging zone, the secondary combustion zone is provided with a burner and a burn-out oxygen-enriched injection lance, the molten slag outlet of the forehearth zone is communicated with the oxidation and burn-out zone, a retaining wall is arranged between the lower part of the forehearth zone and the oxidation and burn-out zone, and the oxidation and burn-out zone is provided with slag outlets at different heights. The process for extracting heavy metals by using the side-blown melting furnace body for high-temperature melting treatment of hazardous waste comprises the following steps: the material is introduced from the top of the flue gas discharging zone, is heated by twice oxygen-enriched combustion in the secondary combustion zone and the belly zone, and is rapidly melted at a temperature of 2000 DEG C or above in the hearth zone and the belly zone, so that the temperature of the molten material in the hearth zone is 1500 DEG C or above, and the molten material flows to the forehearth zone to realize the separation of slag and metal. The top of the flue gas discharging zone is connected with a discharging device, and the side of the flue gas discharging zone is provided with a flue gas discharging port. The inner wall of the flue gas discharging zone, the secondary combustion zone, the shaft zone, the hearth zone and the forehearth zone is a refractory material layer, and the outer wall of the refractory material layer is a water cooling jacket.

2. A side-blown molten bath vessel according to claim 1, wherein The inner wall of the belly zone is a refractory material layer, the outer wall is also a refractory material layer, and the two layers of refractory material layers are water cooling walls.

3. A smelted side-blown vessel according to claim 1, characterized in that The inner wall of the secondary combustion zone is a refractory material layer, the outer wall is also a refractory material layer, and the two layers of refractory material layers are water cooling walls.

4. A smelt of the type defined in claim 1, characterised in that The flue gas discharging zone is designed to be expanded in diameter compared with the secondary combustion zone.

5. A smelt of the type defined in claim 1, characterised in that The secondary air injection lance is horizontally installed and is tangentially injected along the inner wall of the furnace body.

6. A smelt of the type defined in claim 1, characterised in that The bottom of the hearth zone and the bottom of the oxidation and burn-out zone are provided with furnace bottom cooling pipes.

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