System for producing high nickel matte

Abstract

The utility model relates to a system for producing high nickel matte, which comprises an oxygen-enriched converting furnace and an electric furnace, the oxygen-enriched converting furnace comprises a hearth, and the hearth is provided with a first slag tap and a first siphon port; the electric furnace comprises a furnace body, the furnace body is provided with a second slag tap and a second siphon port, and the first slag tap is communicated with the furnace body. The device disclosed by the utility model is good in comprehensive treatment effect on low-grade nickel-containing or nickel-cobalt-containing raw materials and high in recovery rate. The slag is subjected to dilution treatment by adopting the electric furnace, so that better separation of a nickel matte phase and a slag phase is facilitated, the recovery rate of valuable metals such as nickel and cobalt can be improved, the comprehensive treatment effect is further improved, and finally the nickel content in the dilution slag can be reduced to 0.15 wt% or below.

Description

Technical Field

[0001] The utility model relates to a system for producing high-grade nickel matte, and in particular to a system for producing high-grade nickel matte using low-grade nickel raw materials and / or nickel-cobalt raw materials as raw materials. Background Art

[0002] At present, the development of laterite nickel ore is receiving more and more attention. Laterite nickel ore produces low-grade nickel matte, which is then refined into high-grade nickel matte using a converter, an oxygen-enriched converting furnace or a top-blown converting furnace. Converter converting has problems such as lax furnace mouth sealing, large fluctuations in flue gas volume, short furnace life and low nickel and cobalt recovery rate. Other processes have shortcomings such as high nickel content in the waste slag and low cobalt recovery rate.

[0003] To this end, a study has proposed a device for producing high-grade nickel matte from low-grade nickel matte, which includes: an oxygen-enriched blowing furnace, a slag depletion furnace, and a slag chute connecting the oxygen-enriched blowing furnace and the slag depletion furnace; the oxygen-enriched blowing furnace and the slag depletion furnace both include a vertical fixed furnace body, and the slag depletion furnace is also a blowing furnace, especially the slag depletion furnace, which blows oxygen-enriched air into it from both sides of the furnace body, and the slag liquid surface is strongly stirred, and there is no static separation zone, which has an adverse effect on the depletion effect, and the generated slag has a high nickel content and poor technical and economic indicators; in addition, the slag depletion furnace also generates more flue gas, which increases the burden of subsequent flue gas treatment. Utility Model Content

[0004] The purpose of the present invention is to address the deficiencies of the prior art and provide a system for producing high-grade nickel matte with better comprehensive processing effects.

[0005] The technical solutions adopted in this utility model are as follows:

[0006] A system for producing high-grade nickel matte includes an oxygen-enriched blowing furnace, which includes a furnace hearth provided with a first slag tapping port and a first siphon port; and an electric furnace, which includes a furnace body provided with a second slag tapping port and a second siphon port, wherein the first slag tapping port is connected to the furnace body.

[0007] Thus, low-grade nickel or nickel-cobalt raw materials, flux, reducing agents and other charges can be added to the oxygen-enriched smelting furnace, and oxygen-enriched molten pool smelting is carried out to melt the added charges and undergo strong oxidation and slag-forming reactions to form nickel matte and slag; then, the generated nickel matte and slag are precipitated and separated at the bottom of the furnace cylinder, and the obtained high-grade nickel matte is deposited on the inner bottom layer of the furnace cylinder and can be discharged through the first siphon port; the slag with lower nickel content is in the upper layer of the melt in the furnace cylinder and is discharged into the furnace body of the electric furnace through the first slag discharge port, and a sulfiding agent and a reducing agent can be further added to the electric furnace to carry out sulfide depletion, so that valuable metals such as nickel and cobalt are enriched in the low-grade nickel matte in the lower layer, and other impurities are enriched in the depleted slag in the upper layer, the low-grade nickel matte can be discharged through the second siphon port, and the depleted slag can be discharged through the second slag discharge port. By using an electric furnace to carry out depletion treatment on the slag, there is no need to further blow in gases such as oxygen-enriched air, so that the melt in the electric furnace can be kept in a relatively stable state. Although the amount of nickel matte in the melt in the electric furnace is relatively small, it can still be well separated from the slag phase, thereby increasing the recovery rate of valuable metals such as nickel and cobalt, and improving the comprehensive treatment effect. The nickel content in the final depleted slag can be as low as below 0.15wt%. Moreover, since there is no need to further blow in gas, it helps to reduce the amount of flue gas generated and the solid content of the flue gas, which can reduce the burden of subsequent treatment, making the treatment process of low-grade nickel or nickel-cobalt raw materials simpler and having excellent technical and economic indicators.

[0008] Optionally, the low-grade nickel-cobalt raw material contains 20-25wt% nickel, 45-55wt% iron, 0.5-1wt% cobalt, and 20-30wt% sulfur.

[0009] Furthermore, the oxygen-enriched converting furnace is an oxygen-enriched side-blown furnace. Using an oxygen-enriched side-blown furnace improves the suitability of raw materials, enabling good processing of both powdered and bulk materials (e.g., materials with a particle size of up to 50 mm), and reduces pretreatment requirements for low-grade nickel and cobalt raw materials, flux, coal, and other raw materials.

[0010] Optionally, the particle size of the material entering the oxygen-enriched side-blown furnace is ≤50 mm, preferably 5 to 20 mm.

[0011] Optionally, when performing oxygen-enriched side-blowing smelting, the oxygen-to-material ratio is controlled to be 100-180 Nm 3 / t.

[0012] Furthermore, the side wall of the furnace is provided with a plurality of primary air inlets and a plurality of secondary air inlets, and the height of the secondary air inlets is higher than that of the primary air inlets. In this way, oxygen-enriched air (oxygen-enriched air with a concentration of 45-60 vol%) can be blown in through the primary air inlets for oxygen-enriched molten pool smelting, and nickel matte and slag can be precipitated and separated below the primary air inlets; secondary air, such as 21-25 vol% oxygen-enriched air, is blown in through the secondary air inlets, so that the reducing gas generated by the metallurgical reaction is oxidized by the blown-in secondary air in the gas phase space above the oxygen-enriched side-blown furnace, generating high-temperature flue gas containing SO2. After being discharged from the furnace, the flue gas is cooled by waste heat recovery in the waste heat boiler, purified and dusted by the electrostatic precipitator, and then sent to the sulfuric acid workshop for acid production, thereby also helping to maintain the temperature of the material in the furnace.

[0013] The use of an oxygen-enriched side-blown furnace ensures excellent sealing and produces a high, stable, and continuous concentration of SO2 in the flue gas. This facilitates the use of advanced acid production processes, reduces capital investment and operating costs for flue gas treatment, improves sulfur utilization, and contributes to more effective environmental protection. The oxygen-enriched smelting process fully utilizes the chemical reaction heat of sulfur in the raw materials, reduces fuel consumption, and allows the use of inexpensive and readily available coal as fuel.

[0014] Furthermore, the height of the primary tuyere is 210-250 mm lower than the height of the first slag tapping port.

[0015] Furthermore, the vertical distance between the primary tuyere and the slag level in the furnace is 0.7-1.2 m, thereby achieving a more complete reaction and obtaining a slag with lower nickel and cobalt content.

[0016] Furthermore, the heights of the positions of the multiple primary air vents are the same, and the heights of the positions of the multiple secondary air vents are the same.

[0017] Furthermore, the first slag tapping port is connected to the furnace body through a channel.

[0018] Furthermore, a copper water jacket is provided on the outer wall of the channel to increase the service life of the channel.

[0019] Furthermore, the communication position between the channel and the furnace body is located above the slag liquid level in the electric furnace.

[0020] Furthermore, the second slag tapping port is located 0.5-0.65 m lower than the slag liquid level in the electric furnace, thereby better meeting the slag tapping requirements, achieving better clarification and separation effects, and reducing the release of valuable metals such as nickel and cobalt with the slag.

[0021] Compared with the prior art, the utility model has the following advantages:

[0022] (1) The device of the utility model has a good comprehensive treatment effect on low-grade nickel or nickel-cobalt raw materials and a high recovery rate. By using an electric furnace to deplete the slag, it helps to better separate the nickel matte phase and the slag phase, and can improve the recovery rate of valuable metals such as nickel and cobalt, thereby improving the comprehensive treatment effect. The nickel content in the final depleted slag can be as low as 0.15wt% or less. The high-grade nickel matte produced contains ≥60% nickel, 18% to 25% sulfur, and ≤6% iron.

[0023] (2) The device of the present invention also has advantages in terms of simple process and environmental protection. It adopts electric furnace depletion without further blowing in oxygen-rich gas, which helps to reduce the amount of flue gas generated and the solid content of the flue gas, and can reduce the burden of subsequent processing, making the processing process of low-grade nickel or nickel-cobalt raw materials more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a front view of a system for producing high-grade nickel matte according to the present invention.

[0025] Figure 2 This is a top view of a system for producing high-grade nickel matte according to the present invention. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. It should be noted that the embodiments and features of the embodiments of the present invention may be combined unless they conflict. For ease of description, the words "upper," "lower," "left," and "right" appear below merely to indicate the up, down, left, and right directions of the drawings themselves and do not limit the structure. Unless otherwise specified, percentages are by mass.

[0027] Example 1

[0028] See also Figure 1 and Figure 2A system for producing high-grade nickel matte comprises an oxygen-enriched converting furnace 1 and an electric furnace 3. The oxygen-enriched converting furnace 1 comprises a furnace hearth provided with a first slag tapping port 14 and a first siphon port 13, the first siphon port being located lower than the first slag tapping port. The electric furnace 3 comprises a furnace body provided with a second slag tapping port 33 and a second siphon port 32, the second siphon port being located lower than the second slag tapping port. The first slag tapping port 14 is connected to the furnace body. The oxygen-enriched converting furnace 1 is an oxygen-enriched side-blown furnace. The sidewalls of the furnace hearth are provided with a plurality of primary air ports 12 (for injecting 50 vol% oxygen-enriched air) and a plurality of secondary air ports 15 (for injecting 23 vol% oxygen-enriched air). The secondary air ports 15 are located at a height higher than the primary air ports 12. The plurality of primary air ports 12 are located at the same height and are uniformly arranged in sequence along the transverse direction of the furnace hearth. The plurality of secondary air ports 15 are located at the same height and are uniformly arranged in sequence along the transverse direction of the furnace hearth. The height of the primary air inlet 12 is 250 mm lower than the height of the first slag outlet 14. The vertical distance between the primary air inlet 12 and the slag level in the furnace is 0.8 m. The first slag outlet 14 is connected to the furnace body through a channel 2. The outer wall of the channel 2 is provided with a copper water jacket. The connection position between the channel 2 and the furnace body is located above the slag level in the electric furnace. The second slag outlet 33 is located 0.6 m lower than the height of the slag level in the electric furnace, which is 1.55 m. Two first feeding ports 11 and one smoke outlet 16 are provided at the top of the furnace. The first feeding port can be used to add materials such as flux and reducing agent. The smoke outlet 16 is located on the top side of the furnace. The multiple secondary air inlets 15 are arranged close to the side where the smoke outlet is located, which helps to minimize the content of harmful substances in the flue gas. Four second feeding ports 31 are provided at the top of the furnace body, which can be used to add materials such as sulfiding agent and coal.

[0029] The above system is used to process low-grade nickel-cobalt raw materials (Ni: 22.5%, Fe: 51.72%, Co: 0.96%, S: 20.5%). When oxygen-enriched side-blowing smelting is carried out, the low-grade nickel-cobalt raw materials, quartz stone and granular coal are added into the oxygen-enriched side-blowing smelting furnace at a mass ratio of 100:16:4. The smelting temperature is controlled at 1300℃, the smelting cycle is 2.5h, and the oxygen-to-material ratio is 140Nm 3 / t, to obtain high-cobalt nickel matte and slag; when performing electric furnace depletion, slag, sulfiding agent (ferrous sulfide) and reducing agent (granular coal) are added into the electric furnace in a mass ratio of 100:10:3, the temperature is controlled at 1300°C, the depletion time is 6h, and high-cobalt low-cobalt nickel matte and depleted slag are obtained;

[0030] Among them, high nickel matte contains Ni: 70%; S: 22%; Co: 1.555%; Fe: 5.664%;

[0031] The slag contains: Ni: 2.72%; S: 0.04%; Co: 1.03%; Fe: 48.32%; SiO2: 23.48%; CaO: 3.15%;

[0032] High cobalt low matte nickel contains: Ni: 25.26%; S: 28.1%; Co: 5.82%; Fe: 37.26%;

[0033] The depleted slag contains: Ni: 0.13%; SiO2: 25.36%; Fe: 47.23%.

[0034] It can be seen that the nickel content of the depleted slag of the present invention is only 0.13%, and the high-cobalt low-matte nickel contains Ni25.26% and Co: 5.82%, which are better than the solution using two blowing treatments in the prior art.

[0035] Comparative Example 1

[0036] Example 1 was repeated, with the only difference being that the second slag tapping port 33 was located 0.85 m lower than the slag level in the electric furnace.

[0037] At this time, the depleted slag contains: Ni: 0.25%; SiO2: 25.25%; Fe: 47.16%.

[0038] The contents described in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent modifications to the present invention made by those skilled in the art fall within the scope defined by the claims attached to this application.

Claims

1. A system for producing high-grade nickel matte, comprising an oxygen-enriched blowing furnace (1), wherein the oxygen-enriched blowing furnace (1) comprises a furnace hearth, wherein the furnace hearth is provided with a first slag tapping port (14) and a first siphon port (13); wherein: The electric furnace (3) also includes an electric furnace (3), wherein the electric furnace (3) includes a furnace body, a second slag tapping port (33) and a second siphon port (32) are provided on the furnace body, and the first slag tapping port (14) is connected to the furnace body.

2. The system according to claim 1, wherein: The oxygen-enriched blowing furnace (1) is an oxygen-enriched side-blowing furnace.

3. The system according to claim 1, wherein: A plurality of primary air ports (12) and a plurality of secondary air ports (15) are provided on the side wall of the furnace, and the height of the secondary air ports (15) is higher than the height of the primary air ports (12).

4. The system according to claim 3, characterized in that The height of the location of the primary air inlet (12) is 210-250 mm lower than the height of the location of the first slag outlet (14).

5. The system according to claim 3, wherein: The vertical distance between the primary air inlet (12) and the slag liquid level in the furnace is 0.7-1.2 m.

6. The system according to claim 3, wherein: The multiple primary air ports (12) are located at the same height, and the multiple secondary air ports (15) are located at the same height.

7. The system according to any one of claims 1 to 6, characterized in that: The first slag tapping port (14) is connected to the furnace body via a channel (2).

8. The system according to claim 7, characterized in that The outer wall of the channel (2) is provided with a copper water jacket.

9. The system according to claim 7, wherein: The communication position between the channel (2) and the furnace body is located above the slag liquid level in the electric furnace.

10. The system according to any one of claims 1 to 6, characterized in that: The second slag tapping port (33) is located 0.5-0.65 m lower than the slag liquid level in the electric furnace.

Images