A non-ferrous metal smelting slag enhanced depletion process and enhanced depletion furnace

Abstract

The present invention discloses a process for strengthening the depletion of non-ferrous metal smelting slag and a furnace for strengthening the depletion, which belongs to the technical field of non-ferrous metallurgy. The process of the present invention can significantly reduce the nickel content index of non-ferrous metal slag and improve the recovery rate of the metal smelting process of the non-ferrous metallurgical furnace. The present invention provides a strengthening depletion furnace, which completes the functions of depletion and sedimentation in a strengthening depletion electric furnace, optimizes the process and saves investment; on the other hand, the flue gas treatment system can be combined together to save costs. This method can significantly reduce the nickel content index of non-ferrous metal slag and improve the recovery rate of the metal smelting process of the non-ferrous metallurgical furnace.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metallurgy, and in particular relates to an enhanced depletion process and an enhanced depletion furnace for nonferrous metal smelting slag. Background Art

[0002] At present, in the traditional process, lump coal is added to the surface of the molten pool in the furnace (the reducing atmosphere is adjusted by the lump coal) for depletion, producing nickel matte and slag. The slag flows into the settling area of ​​the electric furnace, and the nickel matte is discharged into the copper matte buns and sent to the blowing furnace for blowing. The slag is sold after water quenching.

[0003] In the prior art, non-ferrous metal smelting slag is generally enriched using an ordinary sedimentation electric furnace, which has the following problems: after the enrichment agent and the reducing agent are added, they are not well mixed with the molten slag to be enriched and often float on the slag surface, resulting in a poor enrichment effect; it is not easy to have a reducing atmosphere in the enrichment electric furnace, and the nickel content of the electric furnace slag cannot be reduced.

[0004] Patent 202010049546.1 discloses a one-step nickel smelting system and a one-step nickel smelting method. The one-step nickel smelting device is an integrated device, which includes a furnace body, and a molten pool smelting zone and a reduction depletion zone are sequentially arranged inside the furnace body; the molten pool smelting zone has a first feeding port and a first blast port, and the first feeding port is connected to a raw material conveying device. The molten pool smelting zone is used to smelt the nickel sulfide concentrate to produce high nickel matte, smelting slag and flue gas containing 35-65wt% nickel; the reduction depletion zone is provided with a first charging port and a first blast port, and the first charging ... The depletion zone is connected with the molten pool smelting zone, and the reduction depletion zone has a second feeding port, a second blast port and a smoke outlet. The reduction depletion zone is used to make the smelting slag undergo a depletion reaction to produce depleted slag and a first metalized nickel matte. The equipment processes nickel sulfide concentrate as raw material and produces high-grade nickel matte through smelting. It does not require blowing in a blowing furnace, but the depletion in this process is the depletion of the small front bed in the side-blown furnace. The depletion is a simple depletion and the depletion effect is not thorough, and it is not suitable for non-ferrous metal smelting slag. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide an enhanced depletion process and an enhanced depletion furnace for non-ferrous metal smelting slag, by which the nickel content of the non-ferrous metal slag can be greatly reduced, thereby improving the recovery rate of the metal smelting process of the non-ferrous metallurgical furnace.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides an enhanced depletion process for nonferrous metal smelting slag, comprising the following steps:

[0008] S1. Mixing non-ferrous metal smelting slag, a sulfiding agent, and a first reducing agent according to a set ratio to obtain a mixed material that meets the process requirements;

[0009] S2, adding the mixed material obtained in step S1 into an enhanced depletion furnace, wherein the enhanced depletion furnace comprises a furnace body, wherein a depletion zone and an electric heat precipitation zone are sequentially arranged inside the furnace body, and during the depletion process, the temperature is controlled to be 1250-1300° C., and a second reducing agent is sprayed into the smelting slag in the furnace, and the smelting slag molten pool is fully stirred to ensure that the sulfiding agent, the first reducing agent and the non-ferrous metal smelting slag are fully mixed to complete the physical and chemical reaction;

[0010] S3, the furnace bottom of the depletion zone is higher than the electric heat settling zone, and the depleted slag flows into the electric heat settling zone through the bottom of the partition wall water jacket for settling, completing the separation of the smelting slag and the reduced metal to obtain the enhanced depleted product and the depleted electric furnace slag;

[0011] S4. The enhanced depleted product obtained in step S3 is sent to a blowing furnace for blowing, and the depleted electric furnace slag is water quenched and sold outside.

[0012] In a preferred embodiment, in step S1, the non-ferrous metal smelting slag is nickel-copper smelting slag. If the nickel-copper smelting slag is a solid cold material, the non-ferrous metal smelting slag, the sulfiding agent, and the first reducing agent are mixed in a ratio of (10-30):(1-3):1;

[0013] If the nickel-copper smelting slag is a high-temperature melt, the sulfiding agent and the first reducing agent are mixed in a ratio of (1-3):1, dried, and pelletized, and then the resulting pellets are added to the melt.

[0014] In a preferred embodiment, the first reducing agent is one or more of lump coal, coke, and semi-coke; the first reducing agent is added from the top of the furnace to ensure the heat of the molten pool and the reducing atmosphere in the upper part.

[0015] In a more preferred embodiment, in step S1, the sulfiding agent comprises the following components in weight percentage: Ni 5% to 10%, Cu 2.0% to 5.0%, Fe 22% to 35%, S 20% to 28%, SiO2 15% to 25%, MgO 5% to 12%;

[0016] Alternatively, the vulcanizing agent includes the following components in weight percentage: Cu 15% to 30%, Fe 20% to 30%, S 25% to 30%, SiO2 10% to 15%, and MgO 1% to 2%.

[0017] In a preferred embodiment, in step S1, the non-ferrous metal smelting slag is zinc leaching slag, and only the first reducing agent is added during the depletion process. The zinc leaching slag and the first reducing agent are mixed in a ratio of (1-3):1 to obtain a mixed material that meets the process requirements.

[0018] In a more preferred embodiment, in step S1, the zinc leaching slag comprises the following components in weight percentage: Zn 15% to 20%, Fe 10% to 15%, S 20% to 28%, SiO2 1% to 5%.

[0019] In a preferred solution, in step S2, the slag surface in the depleted zone is maintained at a depth of 1.5 to 2 m, and a molten pool composed of smelting slag is provided with spray guns on the end wall, side wall and furnace top (the long one is called the side wall, the short one is called the end wall, and the two ends are the end walls), and the second reducing agent is sprayed into the molten pool to create a reducing atmosphere in the molten pool.

[0020] In a more preferred embodiment, the second reducing agent is one or more of natural gas, granular coal, and coal powder.

[0021] In a preferred solution, in step S3, a water-cooled flue is provided at the exhaust port of the enhanced depletion furnace, and secondary air is introduced into the flue to ensure that carbon monoxide and elemental sulfur in the flue gas can be completely burned and the residual oxygen concentration in the flue gas is controlled at 2% to 3%. This part of the flue gas then recovers heat through the heat pipe waste heat boiler and enters the dust collection system and the acid production system for treatment before meeting the emission standards.

[0022] In a preferred solution, in step S3, the strengthened depleted slag is discharged intermittently, the grade of the produced matte is 10% to 55%, and the discharge temperature is controlled at 1200 to 1500°C.

[0023] In a preferred embodiment, in step S4, the oxides of the depleted electric slag are mainly FeO and SiO2. When the depleted furnace is discharged, the slag is sampled and analyzed, and the amount of the sulfiding agent and the first reducing agent added to the auxiliary material bin feeder is adjusted according to the analysis results. The amount of the sulfiding agent and the first reducing agent added is 5% to 10% of the amount of the smelting slag, and the iron-silicon ratio is controlled at 0.7 to 1.4. The nickel content in the depleted electric slag is controlled to be less than 0.3%, and the copper content is less than 0.2%, so as to reduce the viscosity of the slag and reduce the content of valuable metals such as nickel and copper entrained in the slag.

[0024] In a more preferred embodiment, in step S4, when the nickel-copper smelting slag is depleted, the iron-silicon ratio of the produced depleted electric furnace slag is 1.1 to 1.3.

[0025] The present invention also provides an enhanced depletion furnace used in the enhanced depletion process, comprising a furnace body, wherein a depletion zone and an electric heat precipitation zone are sequentially arranged inside the furnace body;

[0026] The furnace bottom of the depletion zone is higher than the furnace bottom of the electric heat precipitation zone, a partition wall water jacket is provided between the depletion zone and the electric heat precipitation zone, and a connecting channel is formed below the partition wall water jacket;

[0027] The top of the depletion zone is provided with a charging port, which is connected to the top of the furnace body through a chute; the end wall, side wall and top of the depletion zone are provided with a spray gun;

[0028] The electrothermal deposition zone is provided with a self-baking electrode, and the self-baking electrode extends through the furnace body to the inside of the electrothermal deposition zone;

[0029] The bottom of the electrothermal settling zone is provided with a discharge port for enhanced depleted products, and the upper part of the side wall of the electrothermal settling zone is provided with a discharge port for depleted electric furnace slag;

[0030] The depletion zone and the electrothermal precipitation zone are both provided with smoke exhaust ports.

[0031] Furthermore, the furnace bottoms of the depletion zone and the electrothermal settling zone form steps, which is conducive to the depletion slag melt flowing into the electrothermal settling zone for settling.

[0032] Furthermore, the spray gun includes a side-blowing spray gun and a top-blowing spray gun; the side-blowing spray gun is arranged on the end wall and the side wall of the depletion zone; and the top-blowing spray gun is arranged on the top of the depletion zone.

[0033] Specifically, three-sided side-blowing lances blow natural gas toward the slag layer, so that the sulfiding agent, the reducing agent and the non-ferrous metal smelting slag are fully mixed, which has a heating and stirring effect.

[0034] The top-blowing lance has two functions: 1) to spray natural gas into the molten pool to create a reducing atmosphere in the molten pool; 2) to play a heat-insulating role in non-depleted production to ensure the molten pool temperature in the depleted area.

[0035] Furthermore, the smoke exhaust port is provided with a water-cooled flue, and the water-cooled flue is connected to a waste heat recovery system, a dust collection system, and an acid production system.

[0036] Furthermore, a secondary air outlet is provided at the water-cooled flue.

[0037] Compared with the prior art, the beneficial technical effects of the present invention are:

[0038] (1) The present invention provides an enhanced depletion process for nonferrous metal smelting slag. By adopting this nickel slag depletion method, the valuable metal index of the smelting slag is lower than that of the traditional depleted electric furnace. Taking the depleted nickel smelting slag as an example, the nickel index of the original ordinary depleted electric furnace slag is about 0.35%, and the nickel index of the slag of the new depleted electric furnace is about 0.25%. Based on the annual processing volume of 200,000 tons of slag, the valuable metals recovered from the nickel slag are 200 tons of metallic nickel, creating a benefit of 17 million yuan.

[0039] (2) The enhanced depletion furnace of the present invention completes the functions of depletion and sedimentation in one enhanced depletion electric furnace, optimizes the process and saves investment; on the other hand, the flue gas treatment system can be combined together, saving costs and being beneficial to environmental protection. The enhanced depletion furnace can significantly reduce the nickel content index of non-ferrous metal slag and improve the recovery rate of the metal smelting process of the non-ferrous metallurgical furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the structure of the enhanced depletion furnace;

[0041] Figure 2Device connection diagram in Example 1 of the present invention.

[0042] In the figure: 1-depletion zone; 2-electrothermal sedimentation zone; 3-partition wall water jacket; 4-feeding port; 5-chute; 6-self-baking electrode; 7-enhanced depletion product discharge port; 8-depleted electric furnace slag discharge port; 9-smoke exhaust port; 10-side blowing spray gun; 11-top blowing spray gun; 12-water cooling flue; 13-depletion zone copper water jacket; 14-settlement zone copper water jacket. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] In the embodiment, the nickel-copper smelting slag mainly comprises:

[0045] Component Ni Cu Co Fe S <![CDATA[SiO2]]> CaO wt% 1.50 0.50 0.13 32.18 1.20 29.25 3.30

[0046] Unless otherwise specified in this embodiment, the reagents used are all common commercial products or prepared by conventional means, and the equipment used are all conventional equipment in the art. The following are some embodiments of the inventor's experiments:

[0047] The following is further described by specific embodiments and drawings:

[0048] Example 1

[0049] A process for strengthening the depletion of nonferrous metal smelting slag comprises the following steps:

[0050] (1) Ingredients:

[0051] If the nickel-copper smelting slag is solid cold material, the nickel-copper smelting slag, sulfiding agent and lump coal are mixed in a ratio of 10:1:0.5; if the slag is a high-temperature melt, the sulfiding agent and lump coal are mixed in a ratio of 2:1, dried and pressed into balls, and the iron-silicon ratio of the slag produced when the nickel and copper smelting slag is depleted reaches 1.1-1.3, and the mixed material that meets the process requirements is obtained and added to the enhanced depletion electric furnace;

[0052] Table 1 Composition of sulfiding agent (nickel concentrate)

[0053] Component Ni Cu Co S Fe CaO <![CDATA[SiO2]]> MgO wt% 8.7 4.1 0.32 21.44 27.84 2.4 16.5 7.50

[0054] (2) Depletion:

[0055] 1) Adopt enhanced depletion electric furnace depletion, at a high temperature of 1250℃~1300℃, use side-blowing spray gun to spray natural gas to fully stir the slag molten pool, ensure that the sulfiding agent, depleting agent and slag are fully mixed, and complete the physical and chemical reaction; at the same time, the top-blowing spray gun can also perform the heat preservation function during non-depletion production to ensure the molten pool temperature in the depletion zone;

[0056] 2) The height of the bottom of the reinforced depletion electric furnace is higher than the electric heat settling zone. The depleted slag flows into the electric heat settling zone through the bottom of the partition wall water jacket for settling, completing the separation of the side-blown slag and the low-grade nickel matte, thereby achieving the purpose of recovering the metallic nickel in the side-blown slag. The slag surface in the depletion zone is maintained at a depth of 1.6m to 2m. The molten pool composed of the side slag is equipped with spray guns on the end wall, side wall and furnace top to spray natural gas into the molten pool, so that the molten pool is a reducing atmosphere, and the natural gas is blown toward the slag layer;

[0057] 3) Lump coal is added from the top of the furnace as a reducing agent to ensure the heat of the molten pool and the reducing atmosphere in the upper part;

[0058] 4) Strengthen the introduction of secondary air into the flue at the top of the depleted electric furnace to ensure that the carbon monoxide and elemental sulfur in the flue gas can be completely burned, and the residual oxygen concentration in the flue gas is controlled at 2% to 3%. After this part of the flue gas recovers heat through the heat pipe waste heat boiler, it enters the dust collection system and the acid production system for treatment and then meets the emission standards;

[0059] 5) The nickel matte from the enhanced depletion furnace is sent to the blowing furnace for blowing, and the slag is returned to the slag depletion furnace for treatment. The main component analysis is shown in Table 2-3.

[0060] Table 2 Nickel matte units produced by enhanced depletion electric furnace (wt%)

[0061] Ni Cu Co Fe S 21.4 9.23 0.64 20 22

[0062] Table 3 Units of components of waste slag produced by enhanced depletion electric furnace (wt%)

[0063] Ni Fe Cu SiO2 CaO MgO 0.22 33 0.68 27.5 4 11.6

[0064] like Figure 1 - 2 The embodiment 1 adopts an enhanced depletion furnace, comprising a furnace body, wherein a depletion zone 1 and an electric heat precipitation zone 2 are sequentially arranged inside the furnace body;

[0065] The furnace bottom of the depletion zone 1 is higher than the furnace bottom of the electric heat precipitation zone 2. A partition wall water jacket 3 is provided between the depletion zone 1 and the electric heat precipitation zone 2, and a connecting channel is formed below the partition wall water jacket 3.

[0066] A charging port 4 is provided at the top of the depletion zone 1, and the charging port 4 is connected to the top of the furnace body through a chute 5; spray guns are provided at the end wall, side wall and top of the depletion zone 1;

[0067] The electrothermal deposition zone 2 is provided with a self-baking electrode 6, which passes through the furnace body and extends to the inside of the electrothermal deposition zone;

[0068] The bottom of the electrothermal settling zone 2 is provided with a discharge port 7 for the enhanced depleted product, and the upper part of the side wall of the electrothermal settling zone is provided with a discharge port 8 for the depleted electric furnace slag;

[0069] The depletion zone 1 and the electrothermal precipitation zone 2 are both provided with smoke exhaust ports 9 .

[0070] The spray guns include a side-blowing spray gun 10 and a top-blowing spray gun 11 ; the side-blowing spray gun 10 is arranged on the end wall and the side wall of the depletion zone 1 ; and the top-blowing spray gun 11 is arranged on the top of the depletion zone 1 .

[0071] The smoke exhaust port 9 is provided with a water-cooled flue 12 , which is connected to a waste heat recovery system, a dust collection system, and an acid-making system; a secondary air outlet is provided at the water-cooled flue 12 .

[0072] Example 2

[0073] A process for strengthening the depletion of nonferrous metal smelting slag comprises the following steps:

[0074] (1) Ingredients:

[0075] If the nickel-copper smelting slag is solid cold material, the nickel-copper smelting slag, sulfiding agent and lump coal are mixed in a ratio of 10:1:0.5; if the slag is a high-temperature melt, the sulfiding agent and lump coal are mixed in a ratio of 2:1, dried and pressed into balls, and the iron-silicon ratio of the slag produced when the nickel and copper smelting slag is depleted reaches 1.1-1.3, and the mixed material that meets the process requirements is obtained and added to the enhanced depletion electric furnace;

[0076] Table 4 Sulfiding agent composition (nickel concentrate)

[0077] Component Ni Cu Co S Fe CaO <![CDATA[SiO2]]> MgO wt% 7.8 2.60 0.30 20.45 25.85 4.10 15 7.00

[0078] (2) Depletion:

[0079] 1) Adopt enhanced depletion electric furnace depletion, at a high temperature of 1250℃~1300℃, use side-blowing spray gun to spray natural gas to fully stir the slag molten pool, ensure that the sulfiding agent, depleting agent and slag are fully mixed, and complete the physical and chemical reaction; at the same time, the top-blowing spray gun can also perform the heat preservation function during non-depletion production to ensure the molten pool temperature in the depletion zone;

[0080] 2) The height of the bottom of the reinforced depletion electric furnace is higher than the electric heat settling zone. The depleted slag flows into the electric heat settling zone through the bottom of the partition wall water jacket for settling, completing the separation of the side-blown slag and the low-grade nickel matte, thereby achieving the purpose of recovering the metallic nickel in the side-blown slag. The slag surface in the depletion zone is maintained at a depth of 1.5m to 2m. The molten pool composed of the side slag is equipped with spray guns on the end wall, side wall and furnace top to spray natural gas into the molten pool, so that the molten pool is a reducing atmosphere, and the natural gas is blown toward the slag layer;

[0081] 3) Lump coal is added from the top of the furnace as a reducing agent to ensure the heat of the molten pool and the reducing atmosphere in the upper part;

[0082] 4) Strengthen the introduction of secondary air into the flue at the top of the depleted electric furnace to ensure that the carbon monoxide and elemental sulfur in the flue gas can be completely burned, and the residual oxygen concentration in the flue gas is controlled at 2% to 3%. After this part of the flue gas recovers heat through the heat pipe waste heat boiler, it enters the dust collection system and the acid production system for treatment and then meets the emission standards;

[0083] 5) The nickel matte from the intensified depleted electric furnace is sent to the blowing furnace for blowing. After the slag is quenched with water, it is sold out. The main component analysis is shown in Table 5-6.

[0084] Table 5 Nickel matte units produced by enhanced depletion electric furnace (wt%)

[0085] Ni Cu Co Fe S 19 5.85 0.70 25.50 22.51

[0086] Table 6: Composition units of waste slag produced by enhanced depletion electric furnace (wt%)

[0087] Ni Cu Co Fe <![CDATA[SiO2]]> CaO MgO 0.20 0.15 0.05 33.85 28.20 3.50 10.50

[0088] Example 3

[0089] A process for strengthening the depletion of nonferrous metal smelting slag comprises the following steps:

[0090] (1) Ingredients:

[0091] If the nickel-copper smelting slag is solid cold material, the nickel-copper smelting slag, sulfiding agent and lump coal are mixed in a ratio of 10:1:0.5; if the slag is a high-temperature melt, the sulfiding agent and lump coal are mixed in a ratio of 2:1, dried and pressed into balls, and the iron-silicon ratio of the slag produced when the nickel and copper smelting slag is depleted reaches 1.1-1.3, and the mixed material that meets the process requirements is obtained and added to the enhanced depletion electric furnace;

[0092] Table 7 Sulfiding agent composition (copper concentrate)

[0093] Component Cu Co S Fe CaO <![CDATA[SiO2]]> MgO wt% 21 0.25 28 25 4.50 13 2

[0094] (2) Depletion:

[0095] 1) Adopt enhanced depletion electric furnace depletion, at a high temperature of 1250℃~1300℃, use side-blowing spray gun to spray natural gas to fully stir the slag molten pool, ensure that the sulfiding agent, depleting agent and slag are fully mixed, and complete the physical and chemical reaction; at the same time, the top-blowing spray gun can also perform the heat preservation function during non-depletion production to ensure the molten pool temperature in the depletion zone;

[0096] 2) The bottom of the reinforced depletion electric furnace is higher than the electric heat settling zone. The depleted slag flows into the electric heat settling zone through the bottom of the partition wall water jacket for settling, completing the separation of copper slag and matte, thereby achieving the purpose of recovering metallic copper in copper smelting slag. The slag surface in the depletion zone is maintained at a depth of 1.5m to 2m. The molten pool composed of copper smelting slag is equipped with spray guns on the end wall, side wall and furnace top to spray natural gas into the molten pool, so that the molten pool is a reducing atmosphere, and the natural gas is blown toward the slag layer;

[0097] 3) Lump coal is added from the top of the furnace as a reducing agent to ensure the heat of the molten pool and the reducing atmosphere in the upper part;

[0098] 4) Strengthen the introduction of secondary air into the flue at the top of the depleted electric furnace to ensure that the carbon monoxide and elemental sulfur in the flue gas can be completely burned, and the residual oxygen concentration in the flue gas is controlled at 2% to 3%. After this part of the flue gas recovers heat through the heat pipe waste heat boiler, it enters the dust collection system and the acid production system for treatment and then meets the emission standards;

[0099] 5) The matte from the intensified depleted electric furnace is sent to the converting furnace for converting. After the slag is quenched with water, it is sold. The main component analysis is shown in Table 8-9.

[0100] Table 8: Matte units produced by enhanced depletion furnace (wt%)

[0101] Cu Fe S 51.8 22 23

[0102] Table 9: Composition units of waste slag produced by enhanced depletion electric furnace (wt%)

[0103] Cu Fe <![CDATA[SiO2]]> CaO S 0.5 27 29.22 1.07 1.33

[0104] Example 4

[0105] A process for strengthening the depletion of nonferrous metal smelting slag comprises the following steps:

[0106] (1) Ingredients:

[0107] If the nickel-copper smelting slag is solid cold material, the nickel-copper smelting slag, sulfiding agent and lump coal are mixed in a ratio of 10:1:0.5; if the slag is a high-temperature melt, the sulfiding agent and lump coal are mixed in a ratio of 2:1, dried and pressed into balls, and the iron-silicon ratio of the slag produced when the nickel and copper smelting slag is depleted reaches 1.1-1.3, and the mixed material that meets the process requirements is obtained and added to the enhanced depletion electric furnace;

[0108] Table 10 Sulfiding agent composition (copper concentrate)

[0109] Component Cu Co S Fe CaO <![CDATA[SiO2]]> MgO wt% 22 0.28 29 28 3.50 12 1.5

[0110] (2) Depletion:

[0111] 1) Adopt enhanced depletion electric furnace depletion, at a high temperature of 1250℃~1300℃, use side-blowing spray gun to spray natural gas to fully stir the slag molten pool, ensure that the sulfiding agent, depleting agent and slag are fully mixed, and complete the physical and chemical reaction; at the same time, the top-blowing spray gun can also perform the heat preservation function during non-depletion production to ensure the molten pool temperature in the depletion zone;

[0112] 2) The bottom of the reinforced depletion electric furnace is higher than the electric heat settling zone. The depleted slag flows into the electric heat settling zone through the bottom of the partition wall water jacket for settling, completing the separation of copper slag and matte, thereby achieving the purpose of recovering metallic copper in copper smelting slag. The slag surface in the depletion zone is maintained at a depth of 1.5m to 2m. The molten pool composed of copper smelting slag is equipped with spray guns on the end wall, side wall and furnace top to spray natural gas into the molten pool, so that the molten pool is a reducing atmosphere, and the natural gas is blown toward the slag layer;

[0113] 3) Lump coal is added from the top of the furnace as a reducing agent to ensure the heat of the molten pool and the reducing atmosphere in the upper part;

[0114] 4) Strengthen the introduction of secondary air into the flue at the top of the depleted electric furnace to ensure that the carbon monoxide and elemental sulfur in the flue gas can be completely burned, and the residual oxygen concentration in the flue gas is controlled at 2% to 3%. After this part of the flue gas recovers heat through the heat pipe waste heat boiler, it enters the dust collection system and the acid production system for treatment and then meets the emission standards;

[0115] 5) The matte from the intensified depleted electric furnace is sent to the converting furnace for converting. After the slag is quenched with water, it is sold out. The main component analysis is shown in Table 11-12.

[0116] Table 11: Matte units produced by enhanced depletion furnace (wt%)

[0117] Cu Fe S 54.2 23 29

[0118] Table 12: Composition units of waste slag produced by enhanced depletion electric furnace (wt%)

[0119] Cu Fe <![CDATA[SiO2]]> CaO S 0.53 31.3 34.4 1.91 29

[0120] Example 5

[0121] A process for strengthening the depletion of nonferrous metal smelting slag comprises the following steps:

[0122] (1) Ingredients:

[0123] The zinc leaching slag and lump coal are mixed in a ratio of 2:1, and then dried and pressed into balls to obtain a mixed material that meets the process requirements, and then added into the enhanced depletion electric furnace;

[0124] Table 13 Zinc leaching slag composition

[0125] Component Zn Fe S CaO <![CDATA[SiO2]]> wt% 15 10 1.20 3.50 6

[0126] (2) Depletion:

[0127] 1) Adopt enhanced depletion electric furnace depletion, at a high temperature of 1250℃~1300℃, use side-blowing lance to spray natural gas to fully stir the slag molten pool, ensure that the zinc leaching slag and lump coal are fully mixed, and complete the physical and chemical reaction; at the same time, use top-blowing lance, which can also perform the heat preservation function during non-depletion production to ensure the molten pool temperature in the depletion zone;

[0128] 2) The bottom of the reinforced depletion electric furnace is higher than the electric heat settling zone. The depleted slag flows into the electric heat settling zone through the bottom of the partition wall water jacket for settling to complete the melting of the zinc slag. The slag surface in the depletion zone is kept at a depth of 1.5m to 2m. The molten pool composed of zinc smelting slag is equipped with spray guns on the end wall, side wall and furnace top to spray natural gas into the molten pool, so that the molten pool is a reducing atmosphere, and the natural gas is blown toward the slag layer. Zinc vapor is introduced into the air from the flue to make zinc oxide, and then the zinc oxide product is recovered by using bag dust collector;

[0129] 3) Lump coal is added from the top of the furnace as a reducing agent to ensure the heat of the molten pool and the reducing atmosphere in the upper part;

[0130] 4) Strengthen the introduction of secondary air into the flue at the top of the depleted electric furnace to ensure that the carbon monoxide and elemental sulfur in the flue gas can be completely burned, and the residual oxygen concentration in the flue gas is controlled at 2% to 3%. After this part of the flue gas recovers heat through the heat pipe waste heat boiler, it enters the dust collection system and the acid production system for treatment and then meets the emission standards;

[0131] 5) After water quenching, the depleted slag is sold. The main component analysis is shown in Table 14-15.

[0132] Table 14 Main components of zinc oxide products (wt%)

[0133] Zn Fe <![CDATA[SiO2]]> CaO S 33 2.5 2.25 1.75 3

[0134] Table 15 Zinc slag and main components (wt%)

[0135] Zn Fe <![CDATA[SiO2]]> CaO S 2.47 15 0.5 4.67 8

[0136] Example 6

[0137] A process for strengthening the depletion of nonferrous metal smelting slag comprises the following steps:

[0138] (1) Ingredients:

[0139] The zinc leaching slag and lump coal are mixed in a ratio of 2:1, and then dried and pressed into balls to obtain a mixed material that meets the process requirements, and then added into the enhanced depletion electric furnace;

[0140] Table 16 Zinc leaching slag composition

[0141] Component Zn Fe S CaO <![CDATA[SiO2]]> wt% 16 12 1.50 3.40 6.5

[0142] (2) Depletion:

[0143] 1) Adopt enhanced depletion electric furnace depletion, at a high temperature of 1250℃~1300℃, use side-blowing lance to spray natural gas to fully stir the slag molten pool, ensure that the zinc leaching slag and lump coal are fully mixed, and complete the physical and chemical reaction; at the same time, use top-blowing lance, which can also perform the heat preservation function during non-depletion production to ensure the molten pool temperature in the depletion zone;

[0144] 2) The bottom of the reinforced depletion electric furnace is higher than the electric heat settling zone. The depleted slag flows into the electric heat settling zone through the bottom of the partition wall water jacket for settling to complete the melting of the zinc slag. The slag surface in the depletion zone is kept at a depth of 1.5m to 2m. The molten pool composed of zinc smelting slag is equipped with spray guns on the end wall, side wall and furnace top to spray natural gas into the molten pool, so that the molten pool is a reducing atmosphere, and the natural gas is blown toward the slag layer. Zinc vapor is introduced into the air from the flue to make zinc oxide, and then the zinc oxide product is recovered by using bag dust collector;

[0145] 3) Lump coal is added from the top of the furnace as a reducing agent to ensure the heat of the molten pool and the reducing atmosphere in the upper part;

[0146] 4) Strengthen the introduction of secondary air into the flue at the top of the depleted electric furnace to ensure that the carbon monoxide and elemental sulfur in the flue gas can be completely burned, and the residual oxygen concentration in the flue gas is controlled at 2% to 3%. After this part of the flue gas recovers heat through the heat pipe waste heat boiler, it enters the dust collection system and the acid production system for treatment and then meets the emission standards;

[0147] 5) After water quenching, the depleted slag is sold. The main component analysis is shown in Table 17-18.

[0148] Table 17 Main components of zinc oxide products (wt%)

[0149] Zn Fe <![CDATA[SiO2]]> CaO S 34 2.6 2.30 1.80 2.98

[0150] Table 18 Zinc slag and main components (wt%)

[0151] Zn Fe <![CDATA[SiO2]]> CaO S 2.50 15.50 0.55 5.0 8.20

[0152] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for strengthening the depletion of non-ferrous metal smelting slag, characterized in that: The following steps are involved: S1. Mixing non-ferrous metal smelting slag, a sulfiding agent, and a first reducing agent according to a set ratio to obtain a mixed material that meets the process requirements; S2, adding the mixed material obtained in step S1 into an enhanced depletion furnace, wherein the enhanced depletion furnace is provided with a depletion zone (1) and an electric heat settling zone (2) in sequence, the mixed material undergoes a depletion reaction in the depletion zone (1), the temperature is controlled to be 1250-1300° C., a second reducing agent is sprayed into the smelting slag in the furnace, the smelting slag molten pool is fully stirred, and the sulfiding agent, the first reducing agent and the non-ferrous metal smelting slag are fully mixed to complete the physical and chemical reaction; S3, the depleted slag flows into the electric heat settling zone (2) through the bottom of the partition wall water jacket for settling, completing the separation of the smelting slag and the reduced metal to obtain a reinforced depleted product and depleted electric furnace slag; S4, sending the enhanced depleted product obtained in step S3 to a blowing furnace for blowing, and quenching the depleted electric furnace slag obtained in step S3 for sale; The furnace bottom of the depletion zone (1) is higher than the furnace bottom of the electric heat precipitation zone (2); a partition wall water jacket (3) is provided between the depletion zone (1) and the electric heat precipitation zone (2); and a connecting channel is formed below the partition wall water jacket (3); The top of the depletion zone (1) is provided with a charging port (4), and the charging port (4) is connected to the top of the furnace body through a chute (5); the end wall, side wall and top of the depletion zone (1) are provided with a spray gun; The electrothermal precipitation zone (2) is provided with a self-baking electrode (6), and the self-baking electrode (6) passes through the furnace body and extends into the interior of the electrothermal precipitation zone; The bottom of the electrothermal settling zone (2) is provided with a discharge port (7) for enhanced depleted products, and the upper portion of the side wall of the electrothermal settling zone is provided with a discharge port (8) for depleted electric furnace slag; The depletion zone (1) and the electrothermal precipitation zone (2) are both provided with smoke exhaust ports (9).

2. The process for strengthening the depletion of nonferrous metal smelting slag according to claim 1, characterized in that: In step S1, the non-ferrous metal smelting slag is nickel-copper smelting slag. If the nickel-copper smelting slag is a solid cold material, the non-ferrous metal smelting slag, the sulfiding agent, and the first reducing agent are mixed in a ratio of (10-30): (1-3): 1; If the nickel-copper smelting slag is a high-temperature melt, the sulfiding agent and the first reducing agent are mixed in a ratio of (1-3):1, dried, and pressed into balls, and then the resulting balls are added to the melt; The first reducing agent is one or more of lump coal, coke, and blue coke; the first reducing agent is added from the top of the furnace to ensure the heat of the molten pool and the reducing atmosphere in the upper part.

3. The process for strengthening the depletion of nonferrous metal smelting slag according to claim 2, characterized in that: In step S1, the sulfiding agent includes the following components in weight percentage: Ni 5%~10%, Cu 2.0%~5.0%, Fe 22%~35%, S 20%~28%, SiO2 15%~25%, MgO 5%~12%; Alternatively, the sulfiding agent includes the following components in weight percentage: Cu 15%~30%, Fe 20%~30%, S 25%~30%, SiO2 10%~15%, MgO 1%~2%.

4. The process for strengthening the depletion of nonferrous metal smelting slag according to claim 1, characterized in that: In step S1, the non-ferrous metal smelting slag is zinc leaching slag, and only the first reducing agent is added in the depletion process. The zinc leaching slag and the first reducing agent are mixed in a ratio of (1-3):1 to obtain a mixed material that meets the process requirements; The zinc leaching slag includes the following components in weight percentage: Zn 15%~20%, Fe 10%~15%, S 20%~28%, SiO21%~5%.

5. The process for strengthening the depletion of nonferrous metal smelting slag according to claim 1, characterized in that: In step S2, the slag surface in the depleted zone is maintained at a depth of 1.5 to 2 m. The molten pool is composed of smelting slag. Spray guns are arranged on the end wall, the side wall and the top of the furnace to spray the second reducing agent into the molten pool to create a reducing atmosphere in the molten pool. The second reducing agent is one or more of natural gas, granular coal, and coal powder.

6. The process for strengthening the depletion of nonferrous metal smelting slag according to claim 1, characterized in that: In step S4, the oxides of the depleted electric slag are mainly FeO and SiO2. When the depleted furnace is discharged, the slag is sampled and analyzed, and the amount of the sulfiding agent and the first reducing agent added to the auxiliary material bin feeder is adjusted according to the analysis results. The amount of the sulfiding agent and the first reducing agent added is 5% to 10% of the amount of smelting slag, and the iron-silicon ratio is controlled at 0.7 to 1.

4. The nickel content in the depleted electric slag is controlled to be less than 0.3%, and the copper content is controlled to be less than 0.2%, thereby reducing the viscosity of the slag and reducing the content of valuable metals such as nickel and copper entrained in the slag.

7. The process for strengthening the depletion of nonferrous metal smelting slag according to claim 1, characterized in that: The spray guns comprise a side-blowing spray gun (10) and a top-blowing spray gun (11); the side-blowing spray gun (10) is arranged on the end wall and the side wall of the depletion zone (1); and the top-blowing spray gun (11) is arranged on the top of the depletion zone (1).

8. The process for strengthening the depletion of nonferrous metal smelting slag according to claim 1, characterized in that: The smoke exhaust port (9) is provided with a water-cooled flue (12), and the water-cooled flue (12) is connected to a waste heat recovery system, a dust collection system, and an acid production system.

9. The process for strengthening the depletion of nonferrous metal smelting slag according to claim 8, characterized in that: The water-cooled flue (12) is provided with a secondary air outlet.

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