A process for smelting and reusing high-carbon ferrochrome neutral slag

Abstract

This invention discloses a process for the smelting and reuse of neutral slag from high-carbon ferrochrome smelting, belonging to the field of ferroalloy metallurgical technology. This process addresses the challenge of residual recovery from neutral slag in high-carbon ferrochrome smelting by utilizing a core-shell nanocomposite modifier and a gradient magnetic field to achieve integrated slag pre-reduction, modification, and smelting reuse. Using neutral slag, ferrochrome concentrate, carbonaceous reducing agent, and core-shell modifier as raw materials, the mixture is dry-loaded and pre-reduced in a gradient magnetic field rotary kiln, followed by deep melting in a hot-charged submerged arc furnace. Basicity is controlled, and the nano-agent catalyzes the dissolution of Cr2O3 and induces oxygen vacancy network disruption, promoting slag-iron separation. Compared to traditional methods, this process improves recovery rate, reduces energy consumption, produces uniformly dispersed carbides without macroscopic inclusions, and achieves efficient reuse of neutral slag in an economical and environmentally friendly manner.

Description

Technical Field

[0001] This invention belongs to the field of ferroalloy metallurgy technology, specifically, it relates to a process for smelting and reusing neutral slag of high-carbon ferrochrome. Background Technology

[0002] High-carbon ferrochrome smelting mainly adopts the flux method of electric arc furnace (electric arc furnace), using chromite (mainly FeCr2O4, with Cr2O3 content of 40-55wt%), metallurgical coke and limestone as raw materials. The carbothermic reduction reaction is carried out at 1600-1800℃: FeCr2O4+4C→Fe+2Cr+4CO, producing an alloy containing 60-72wt% Cr and 6-8wt% C, while producing 1.1-1.2t / t of neutral slag (CaO / SiO2≈1.0-1.2) of alloy.

[0003] Traditional smelting processes are divided into blast furnace method, electric furnace method, and plasma method, with the electric furnace flux method accounting for over 95%. The process flow includes raw material proportioning (100 parts chromium ore, 25-40 parts coke, 15-30 parts flux), continuous feeding, electrode submersion heating, and slag-iron separation. The temperature gradient within the furnace results in upper solid-phase pre-reduction (950-1200℃, metallization rate 30-50%) and lower liquid-phase deep reduction (>1600℃). However, this process has several drawbacks: First, the chromium recovery rate is only 85-92%, and the Cr2O3 content in the slag is 3-10wt%, resulting in an annual loss of approximately 400,000 tons of Cr2O3. Second, the unit power consumption is 3200-4000 kWh / t, which is higher than the standard (<2800 kWh / t). Third, the alloy purity is low, with Si 1.5-3wt%, P / S >0.05wt%, and coarse carbides (Cr, Fe) 7C3 (>20μm), affecting the decarburization and toughness of downstream stainless steel. Fourth, the neutral slag has poor fluidity and high viscosity (η>0.5Pa·s, 1600℃), which easily carries metal, leading to incomplete separation and macroscopic inclusions >100μm. Neutral slag is characterized by high levels of MgO (8-15 wt%), Al2O3 (15-25 wt%), and spinel phases (MgCr2O4, FeCr2O4), forming a dense silicon-oxygen tetrahedral network. Cr2O3 has low solubility (<2 wt%), limiting reduction kinetics. Chromite reduction is a multi-step process: FeCr2O4 → FeO + Cr2O3 → Fe + Cr2O3 → Cr. Cr2O3 has a high activation energy (>300 kJ / mol), and preferential iron reduction leads to a 8-20% lag in Cr metallization. Slag phase stability inhibits diffusion. Literature shows that at slag basicity of 1.0-1.2, Cr2O3 exists in solid solution or spinel form, and is difficult to separate at temperatures below 1750℃. A MgO / Al2O3 ratio >1.5 further increases viscosity, resulting in a flow index <0.8. The existing technology has prominent pain points: (1) High raw material loss, moisture >10% or SiO2 >5wt% leads to sintering, and the actual Cr2O3 utilization rate is <85%; (2) Insufficient pre-reduction, cold charging furnace charge prolongs the smelting cycle by 8-12 hours, and the power density is <300kW / m³. 2 (3) No interface control, slag network not broken, oxygen vacancy concentration <10 18 / cm 3 , Cr2O3 formation energy barrier >50kJ / mol; (4) High environmental pressure, 4 million tons of slag are stored annually, utilization rate <30%, high Cr leaching risk (>5mg / L), prominent hazardous waste characteristics.

[0004] To address these issues, some scholars have attempted various optimization methods: First, pretreatment in mineral processing, such as gravity separation to recover Cr concentrate from the slag (recovery rate 22%, Cr2O3 > 30 wt%), but this involves high equipment investment and a 20% increase in energy consumption. Second, composite reducing agents, reducing power consumption to 2400 kWh / t, but resulting in carbon excess > 1.2 and an increase in S / P ratio of 0.02 wt%. Third, high-temperature, high-pressure, or hydrogen-based pre-reduction, achieving a metallization rate > 70%, but with expensive hydrogen sources and difficulties in equipment corrosion resistance, resulting in an industrialization rate of < 5%. Fourth, flux optimization, increasing basicity to 1.4-1.5, reducing Cr2O3 to 2%, but exacerbating MgO volatilization and furnace lining erosion, and shortening the cycle time by only 10%. Fifth, nano-additions, such as TiO2 catalyzing Cr2O3 dissolution, but with poor dispersion (< 90%) and high-temperature deactivation, resulting in a recovery rate increase of < 5%.

[0005] Patent literature also reflects limitations: CN108580021B uses dry slag gravity separation and staged grinding to recover 30wt% Cr2O3 concentrate, but only processes tailings and ignores the reduction of the original slag. CN105112663B combines semi-coke production with power consumption of 2250kWh / t, but the pre-reduced pellets have low hot charging rate and are mainly cold-charged, with slag Cr > 5%. CN107385213A directly charges chromium ore powder into the furnace, simplifying the batching, but without magnetic field assistance, the selective reduction is poor, and the Fe / Cr ratio is unbalanced. CN111848187A uses slag to make castables, but Cr leaching is not controlled and is not for smelting reuse. Foreign patents such as US patents emphasize plasma smelting with a recovery rate of 95%, but the energy consumption is > 5000kWh / t, and the scale is small.

[0006] Despite the progress made in the aforementioned technologies, none of them have fundamentally solved the problems of high viscosity of neutral slag, slow selective reduction of Cr, and dynamic interface control: traditional coreless shell-based carriers have a nanoparticle loading of <80% and high-temperature agglomeration; without a gradient magnetic field, the magnetic nucleus cannot directionally enhance the contact with Cr ore, resulting in a kinetic improvement of <10%; lacking the synergy between shell breaking and nucleation, slag-iron separation relies on passive flow, with an inclusion rate >5%. In addition, the parameter windows are narrow (e.g., sintering with a magnetic field >1.5T, and volatilization with an alkalinity >1.5), resulting in poor industrial stability, an overall recovery rate of <90%, and power consumption >2500kWh / t.

[0007] In summary, existing technologies are insufficient to achieve efficient smelting and reuse of high-carbon ferrochrome neutral slag, and innovative processes are urgently needed: developing core-shell nano-modifier-loaded flux, gradient magnetic field-assisted pre-reduction, and dynamic interface-controlled integrated smelting to achieve Cr recovery >95%, power consumption <2200kWh / t, and excellent alloy purity. Summary of the Invention

[0008] To address the problems in existing technologies such as low Cr2O3 recovery rate (<92%), high unit power consumption (>3000kWh / t), coarse alloy carbides (>20μm), poor slag-iron separation (macroscopic inclusions >50μm), and slag resource utilization rate of less than 30% in high-carbon ferrochrome smelting neutral slag, this invention provides a high-carbon ferrochrome neutral slag smelting and reuse process.

[0009] The present invention adopts the following technical solution: a process for smelting and reusing high-carbon ferrochrome neutral slag, comprising the following steps: (1) Preparation of core-shell nanocomposite modifier: take 0.5-1.5 parts of ferric nitrate nonahydrate (CAS No. 7782-61-8) and dissolve it in 10-15 parts of deionized water, add 0.8-2 parts of citric acid (CAS No. 77-92-9), heat and stir to form a magnetic core precursor solution; add the magnetic core precursor solution dropwise to the sol, disperse it by ultrasonication, add 2-4 parts of tetraethyl orthosilicate (CAS No. 78-10-4), continue stirring and calcining; (2) Preparation of precursor mixture: take 50 parts of high-carbon ferrochrome neutral slag and ferrochrome concentrate (main component is FeCr2O4, CAS No. 12001-12-4). 100 parts, carbonaceous reducing agent (mainly metallurgical coke powder, fixed carbon content ≥85wt%, CAS No. 66084-93-1 related) 28-42 parts, calcium flux (mainly quicklime powder, CaO content ≥90wt%, CAS No. 1305-78-8) 18-28 parts and core-shell nanocomposite modifier obtained in step (1) 2-6 parts, first premix the high-carbon ferrochrome neutral slag, core-shell nanocomposite modifier and calcium flux, then add ferrochrome concentrate and carbonaceous reducing agent, shear and mix to obtain a mixture; (3) gradient magnetic field assisted solid pre-reduction: the mixture in step (2) is subjected to solid pre-reduction reaction to obtain high-temperature pre-reduction raw material; (4) hot charging deep smelting and dynamic interface control: the high-temperature pre-reduction raw material obtained in step (3) is smelted and reduced.

[0010] The high-carbon ferrochrome neutral slag contains 25-35 wt% silica, 23-33 wt% magnesium oxide, 15-29 wt% aluminum oxide, 1-5 wt% calcium oxide, 7-13 wt% chromium trioxide, and 1-5 wt% iron oxide.

[0011] Preferably, the preparation method of the sol in step (1) is as follows: take 1 part of titanium tetrachloride (CAS No. 7550-45-0) and dissolve it in 20-30 parts of isopropanol (CAS No. 67-63-0), add 2-5 parts of deionized water and 1-3 parts of ammonia (CAS No. 1336-21-6, mass fraction 25%), stir to form a sol, wherein the mass fraction of ammonia is 25%; the heating and stirring parameters in step (1) are as follows: 100-300 rpm, temperature 80-90℃, time 0.5-1.5h; the ultrasonic dispersion parameters in step (1) are as follows: power 100-200W, frequency 40-45kHz, time 30-60min; the stirring reaction parameters in step (1) are as follows: 200-600 rpm, 4-6h.

[0012] Preferably, the calcination parameters in step (1) are as follows: nitrogen atmosphere, heating rate 3-6℃ / min, temperature 600-750℃, time 3-5h; the zeta potential of the core-shell nanocomposite modifier obtained in step (1) is -40mV, the core particle size is 15-40nm, the shell thickness is 5-15nm, and its specific surface area is 180-350m². 2 / g.

[0013] Preferably, the premixing parameters in step (2) are as follows: time 30-60 min, equipment planetary ball mill, speed 200-400 rpm, ball-to-material ratio 8:1-12:1.

[0014] Preferably, the parameters for shear mixing in step (2) are as follows: using a twin-screw extruder, shearing time 2-4 hours, and shearing rate 1500-2500 s. -1 .

[0015] Preferably, the parameters for the solid-state pre-reduction reaction in step (3) are as follows: argon flow rate 3-6 m³ / h. 3 / t, magnetic field strength at the feed end 0.2-0.5T, at the discharge end 0.8-1.2T, magnetic field gradient 0.3-0.6T / m, the temperature at the feed end gradually increases from 900-1000℃ to 1100-1200℃ at the discharge end, time 2.5-4.5h.

[0016] Preferably, the equipment for the solid pre-reduction reaction in step (3) is a rotary reactor with a rotation speed of 4-8 rpm and an inclination angle of 2-4°. The magnetic field of the rotary reactor is generated by an electromagnetic coil.

[0017] Preferably, the temperature of the high-temperature pre-reduction raw material in step (4) is ≥1000℃; the parameters for smelting and reduction in step (4) are as follows: temperature 1680-1780℃, furnace power density 320-480kW / m³. 2The smelting cycle is 8-12 hours, the slag discharge temperature is 1720-1760℃, and the binary basicity of the slag, CaO / SiO2, is controlled to be 1.2-1.45.

[0018] Preferably, the equipment for smelting and reduction in step (4) is a DC submerged arc furnace, with an electrode insertion depth of 45-65% of the furnace charge height, an inner diameter of 2.5-4m, and an electrode diameter of 600-900mm; in step (4), metallurgical coke powder is added according to the furnace condition to maintain an excess carbon content coefficient of 1.08-1.18, the particle size of the added metallurgical coke powder is <10mm, and the dosage is 0.5-1.5 parts / ton of material.

[0019] Compared with existing technologies, this invention achieves efficient reuse of high-carbon ferrochrome neutral slag through the synergistic effect of core-shell nanocomposite modifiers and gradient magnetic field-assisted pre-reduction, from three levels: interfacial chemistry, kinetics, and phase field regulation. This results in improved chromium recovery, reduced power consumption, and significantly optimized alloy purity. Attached Figure Description

[0020] Figure 1 This is the infrared spectrum of the core-shell nanocomposite modifier prepared in Example 1.

[0021] Figure 2 This is a transmission electron microscope image of the core-shell nanocomposite modifier prepared in Example 1.

[0022] Figure 3 This is a photograph of the modified high-carbon ferrochrome prepared in Example 1. Detailed Implementation

[0023] The present invention will now be described in detail through specific embodiments. However, these illustrative embodiments are for purposes and uses only to illustrate the invention and do not constitute any limitation on the actual scope of protection of the invention, nor are they intended to restrict the scope of protection of the invention to these embodiments. For parameter ranges not mentioned, intermediate values ​​are selected. Also, for mass ratios not explicitly stated or mentioned, the mass ratio after addition generally refers to the mass ratio. Furthermore, in the present invention, the unit of mass is grams (g).

[0024] Example 1.

[0025] The high-carbon ferrochrome neutral slag smelting and reuse process of this embodiment includes the following steps: (1) Preparation of core-shell nanocomposite modifier: Take 1 part (20g) of titanium tetrachloride (CAS No. 7550-45-0) and dissolve it in 25 parts (500g) of isopropanol (CAS No. 67-63-0), add 3 parts (60g) of deionized water and 2 parts (40g) of ammonia water (CAS No. 1336-21-6, mass fraction 25%), and stir at 300rpm on a magnetic stirrer (model IKARW20) to form a sol. At the same time, take 1 part (20g) of ferric nitrate nonahydrate (CAS No. 7782-61-8) and dissolve it in 12 parts (240g) of deionized water, add 1.4 parts (28g) of citric acid (CAS No. 77-92-9), heat to 85℃ and stir for 1 hour to form a magnetic core precursor solution. The magnetic core precursor solution was slowly added dropwise to the sol and ultrasonically dispersed for 45 minutes using an ultrasonic disperser (Branson 2510). Then, 3 portions (60g) of tetraethyl orthosilicate (CAS No. 78-10-4) were added, and the reaction was continued with stirring for 5 hours. After the reaction was complete, the mixture was placed in a tube furnace (Carbolite GeroSTF) under a nitrogen atmosphere and heated to 680℃ at a rate of 4℃ / min, and calcined for 4 hours to obtain a core-shell nanocomposite modifier with an iron oxide (Fe3O4, CAS No. 1317-61-9) core with an average particle size of 28nm, a silicon dioxide (SiO2, CAS No. 7631-86-9) shell with a thickness of 10nm, and an anatase titanium dioxide (TiO2, CAS No. 1317-80-2) coating with a thickness of 18nm. Its infrared spectrum is shown below. Figure 1 As shown, its transmission electron microscope image is as follows. Figure 2 As shown. Its specific surface area is 260 m². 2 / g, with an iron oxide content of 20wt%. Zeta potential is -40mV, water dispersion stability is ≥52 hours, core-shell interface binding energy is >220kJ / mol, and magnetic saturation intensity is 35emu / g. (2) Preparation of precursor mixture: Take 500g of high carbon ferrochrome neutral slag, 1000g of ferrochrome concentrate (main component is FeCr2O4, CAS No. 12001-12-4, Cr2O3 content 46wt%, FeO content 25wt%, SiO2 content 2.5wt%, MgO content 12wt%, moisture 6wt%), 350g of carbonaceous reducing agent (mainly metallurgical coke powder, fixed carbon content 88wt%, ash content 10wt%, volatile matter 4wt%, S content 0.5wt%, CAS No. 66084-93-1), 230g of calcareous flux (mainly quicklime powder, CaO content 92wt%, CAS No. 1305-78-8) and 40g of core-shell nanocomposite modifier obtained in step (1). First, dry premixing was performed for 45 minutes using a planetary ball mill (Fritsch P5, 200 rpm, 350 rpm rotation speed, ball-to-material ratio 10:1) to load the nanoparticles onto the surface of the calcium flux (loading rate 94%). Then, chromite concentrate and carbonaceous reducing agent were added, along with 15% water by weight. The mixture was then extruded using a twin-screw extruder (Coperion ZSK, shear rate 2000 s). -1 (2) High shear mixing for 3 hours to ensure 97% dispersion of nanoparticles in the mixture. (3) Gradient magnetic field assisted solid pre-reduction: The mixture obtained in step (2) is placed in a rotary reactor (3m inner diameter, 6rpm rotation speed, 3° tilt angle) equipped with a temperature gradient and an external gradient magnetic field (magnetic field strength 0.35T at the feed end, 1.0T at the discharge end, gradient 0.45T / m, generated by an electromagnetic coil). Under the protection of an inert atmosphere of argon (CAS No. 7440-37-1) (flow rate 4.5m). 3 / t mixture), from the feed end 980℃ to the discharge end 1150℃ for solid pre-reduction reaction for 3.5 hours, the particle size of the material after pre-reduction is controlled at 12mm. The pre-reduction degree is controlled at 59%, and the chromium metallization rate is 13 percentage points higher than the iron metallization rate. (4) Hot charging deep melting and dynamic interface control: The high temperature pre-reduction raw material (temperature ≥1050℃) obtained in step (3) is directly hot charged into the DC submerged arc furnace (inner diameter 3.2m, electrode diameter 750mm, electrode insertion depth is 55% of the furnace charge height, power density 400kW / m 2 In a smelting cycle of 10 hours, smelting and reduction were carried out at 1720℃, with the binary basicity of the slag (CaO / SiO2) controlled at 1.32 and the power density in the furnace at 400kW / m³. 2According to the furnace condition, 0.8 parts / ton of metallurgical coke powder (particle size <10mm) was added (total addition 800g) to maintain the carbon content excess coefficient at 1.12. The core-shell nanocomposite modifier was used in the smelting process to induce oxygen vacancies through magnetic nuclei, regulate the polymerization of the slag silicon-oxygen network through the shell layer, and act as a heterogeneous nucleating agent until slag-iron separation. The slag discharge temperature was 1740℃, resulting in modified high-carbon ferrochrome. Figure 3 As shown.

[0026] Examples 2-12 and Comparative Examples 1-12.

[0027] All units of mass are grams (g). Except for the parameters listed in the table, all other parameters are exactly the same as in Example 1. The parameter values ​​for each example / comparative example are clear and distinct from each other.

[0028] Table 1: Preparation parameters of core-shell nanocomposite modifier in step (1)

[0029]

[0030] Table 2: Precursor mixing parameters in step (2)

[0031]

[0032] Table 3: Gradient magnetic field-assisted pre-reduction parameters in step (3)

[0033]

[0034] Table 4: Parameters for hot charging deep melting in step (4)

[0035]

[0036] Test Methods and Results: Test Methods: Chromium Recovery (%): The total Cr content in raw materials and products was determined using an inductively coupled plasma optical emission spectrometer (ICP-OES, model ThermoiCAP7400) according to GB / T4698.1-2019, and the recovery rate was calculated. Unit Power Consumption (kWh / t): The total power consumption of the electric furnace was recorded in real time using a power analyzer (model Fluke435) and divided by the qualified alloy yield. Alloy Composition (Cr, C, Si, P, Swt%): Spectrometer (model SPECTROLAB) and infrared carbon-sulfur analyzer (model LECOCS844) were used. Average Carbide Size (μm): The cross-section was observed using a scanning electron microscope (SEM, model HitachiSU8010), and the average value of 50 fields of view was calculated using ImageJ software. Cr2O3 Content in Slag (%): X-ray fluorescence spectrometer (XRF, model PANalyticalAxios). Slag-gold separation effect: Visual inspection and metallographic microscopy were used to observe the size of inclusions (macroscopic non-metallic inclusions >50μm) and measure the density difference.

[0037] Table 5: Performance Test Results

[0038]

[0039] Table 6: Performance Test Results II

[0040]

[0041] Results Analysis and Mechanism Elucidation: Performance data from Examples 1-12 show that the average chromium recovery rate of this process is 96.2% (94.8%-97.1%), the average unit power consumption is 2192 kWh / t (2178-2210 kWh / t), the alloy Cr content is 68.5 wt% (67.8-69.5 wt%), and the Cr2O3 content in the slag is only 1.3% (1.1%-1.7%), which is far superior to the 84.1%, 3065 kWh / t, 63.0 wt%, and 6.0% of Comparative Examples 1-12. This advantage stems from the three-layer synergistic catalytic mechanism of the core-shell nanocomposite modifier (Fe3O4@SiO2@TiO2): the magnetic core (20wt%, 28nm) is directionally enriched to the chromite-Cr2O3 interface under a gradient magnetic field (0.45T / m), accelerating the selective reduction of Cr, with a pre-reduction degree of 59% (chromium metallization rate is 13 percentage points higher than iron), compared to only 45.2% and 5.5 percentage points for the unmodified sample in Comparative Example 1. The SiO2 shell (10nm, Zeta potential -40mV) is activated by Ca... 2+ Bridge and Ti 4+ Replacement-induced silicon-oxygen network [SiO4] 4- →[Si2O7] 6- Reconstruction generates high-density oxygen vacancies, increasing the solubility of Cr2O3 from <2wt% to 6.5wt%, reducing viscosity to η=0.28Pa·s (comparative example >0.5Pa·s), and achieving a flow index of 0.85 under basicity of 1.32, promoting rapid slag-iron separation, with macroscopic inclusions <50μm.

[0042] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection defined by the claims submitted herein.

Claims

1. A process for smelting and reusing high-carbon ferrochrome neutral slag, characterized in that, Includes the following steps: (1) Take 0.5-1.5 parts of ferric nitrate nonahydrate and dissolve it in 10-15 parts of deionized water. Add 0.8-2 parts of citric acid and heat and stir to form a magnetic core precursor solution. Add the magnetic core precursor solution dropwise to the sol, disperse it by ultrasonication, add 2-4 parts of tetraethyl orthosilicate, continue stirring and calcining to obtain a core-shell nanocomposite modifier. (2) Take 50 parts of high-carbon ferrochrome neutral slag, 100 parts of ferrochrome concentrate, 28-42 parts of carbonaceous reducing agent, 18-28 parts of calcium flux and 2-6 parts of the core-shell nanocomposite modifier obtained in step (1). First, premix the high-carbon ferrochrome neutral slag, core-shell nanocomposite modifier and calcium flux, then add ferrochrome concentrate and carbonaceous reducing agent, and shear and mix to obtain a mixture. (3) Perform a solid-state pre-reduction reaction on the mixture in step (2) to obtain a high-temperature pre-reduction raw material. (4) Smelt and reduce the high-temperature pre-reduction raw material obtained in step (3).

2. The high-carbon ferrochrome neutral slag smelting and reuse process according to claim 1, characterized in that, The preparation method of the sol in step (1) is as follows: take 1 part of titanium tetrachloride and dissolve it in 20-30 parts of isopropanol, add 2-5 parts of deionized water and 1-3 parts of ammonia water, stir to form a sol, wherein the mass fraction of ammonia water is 25%; the heating and stirring parameters in step (1) are as follows: 100-300 rpm, temperature 80-90℃, time 0.5-1.5h; the ultrasonic dispersion parameters in step (1) are as follows: power 100-200W, frequency 40-45kHz, time 30-60min; the stirring reaction parameters in step (1) are as follows: 200-600 rpm, 4-6h.

3. The high-carbon ferrochrome neutral slag smelting and reuse process according to claim 1, characterized in that, The calcination parameters in step (1) are as follows: nitrogen atmosphere, heating rate 3-6℃ / min, temperature 600-750℃, time 3-5h; the zeta potential of the core-shell nanocomposite modifier obtained in step (1) is -40mV, the core particle size is 15-40nm, the shell thickness is 5-15nm, and its specific surface area is 180-350m². 2 / g.

4. The high-carbon ferrochrome neutral slag smelting and reuse process according to claim 1, characterized in that, The premixing parameters in step (2) are as follows: time 30-60 min, equipment planetary ball mill, speed 200-400 rpm, ball-to-material ratio 8:1-12:

1.

5. The high-carbon ferrochrome neutral slag smelting and reuse process according to claim 1, characterized in that, The parameters for shear mixing in step (2) are as follows: using a twin-screw extruder, shearing time 2-4 hours, shearing rate 1500-2500 s. -1 .

6. The high-carbon ferrochrome neutral slag smelting and reuse process according to claim 1, characterized in that, The parameters for the solid-state pre-reduction reaction in step (3) are as follows: argon flow rate 3-6 m³ / h. 3 / t, magnetic field strength at the feed end 0.2-0.5T, at the discharge end 0.8-1.2T, magnetic field gradient 0.3-0.6T / m, the temperature at the feed end gradually increases from 900-1000℃ to 1100-1200℃ at the discharge end, time 2.5-4.5h.

7. The high-carbon ferrochrome neutral slag smelting and reuse process according to claim 1, characterized in that, In step (3), the equipment for the solid pre-reduction reaction is a rotary reactor with a rotation speed of 4-8 rpm and an inclination angle of 2-4°. The magnetic field of the rotary reactor is generated by an electromagnetic coil.

8. The high-carbon ferrochrome neutral slag smelting and reuse process according to claim 1, characterized in that, In step (4), the temperature of the high-temperature pre-reduction raw material is ≥1000℃; the parameters for smelting and reduction in step (4) are as follows: temperature 1680-1780℃, furnace power density 320-480kW / m³. 2 The smelting cycle is 8-12 hours, the slag discharge temperature is 1720-1760℃, and the binary basicity of the slag, CaO / SiO2, is controlled to be 1.2-1.

45.

9. The high-carbon ferrochrome neutral slag smelting and reuse process according to claim 1, characterized in that, In step (4), the equipment for smelting and reduction is a DC submerged arc furnace. The electrode insertion depth is 45-65% of the furnace charge height. The inner diameter of the submerged arc furnace is 2.5-4m, and the electrode diameter is 600-900mm. In step (4), metallurgical coke powder is added according to the furnace condition to maintain the excess carbon content coefficient of 1.08-1.

18. The particle size of the added metallurgical coke powder is <10mm, and the dosage is 0.5-1.5 parts / ton of material.

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