Production method of chromium-containing hot metal

Abstract

The present invention discloses a production method of chromium-containing hot metal, comprising: batching, batching chromium iron pellets, fluxes, and coke; feeding, preheating the batch of chromium iron pellets, fluxes, and coke and then adding them from the top of the submerged arc furnace into the submerged arc furnace; smelting, passing an electric current through the electrodes in the submerged arc furnace for smelting, wherein, during the smelting process, pre-reduction of the burden is carried out, and the pre-reduction of the burden includes: purifying the submerged arc furnace gas discharged from the top of the submerged arc furnace during the smelting process, mixing it with hydrogen and coalbed methane to form a mixture of submerged arc furnace gas, hydrogen, and coalbed methane, heating the mixture and then evenly injecting it into the submerged arc furnace from the tuyeres below the burden surface of the submerged arc furnace to pre-reduce the burden in the submerged arc furnace. By using the method of the present invention, the chemical energy of the submerged arc furnace gas is fully utilized, and by pre-reducing the burden with the submerged arc furnace gas, the consumption of coke during the smelting of the submerged arc furnace is significantly reduced, thus achieving the goal of low-carbon smelting.

Description

Technical Field

[0001] The present invention belongs to the technical field of iron and steel smelting, and particularly relates to a production method of chromium-containing hot metal. Background Art

[0002] Chromium-containing hot metal is the main raw material for producing stainless steel. At present, the production process of chromium-containing hot metal is as follows: after roasting chromite ore powder into chromium-iron pellets, it is added to a submerged arc furnace together with a flux and fuel coke for smelting, and finally chromium-containing hot metal is obtained. When using this process to smelt chromium-containing hot metal, the consumption of coke is relatively high, about 500 kg / t, and the CO content in the submerged arc furnace gas discharged during smelting reaches 90%. Although the submerged arc furnace gas can be used for heating, power generation, etc. after being discharged, the chemical energy of CO in it is not fully utilized.

[0003] Therefore, developing a new production method of chromium-containing hot metal to fully utilize CO in the submerged arc furnace gas and achieve low-carbon smelting has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] For this reason, in view of the above technical problems existing in the prior art, the present invention provides a production method of chromium-containing hot metal, including the following steps:

[0005] (1) Batching, batching chromium-iron pellets, flux, and coke;

[0006] (2) Charging, preheating the batch of chromium-iron pellets, flux, and coke and adding them into the submerged arc furnace from the top of the submerged arc furnace;

[0007] (3) Smelting, passing an electric current through the electrodes in the submerged arc furnace for smelting. Among them, during the smelting process, pre-reduction of the furnace charge is carried out. The pre-reduction of the furnace charge includes: after purifying the submerged arc furnace gas discharged from the top of the submerged arc furnace during the smelting process, adding hydrogen and coalbed methane, forming a mixture of submerged arc furnace gas, hydrogen, and coalbed methane, heating the mixture and uniformly injecting it into the submerged arc furnace from the tuyeres under the furnace charge surface of the submerged arc furnace to pre-reduce the furnace charge in the submerged arc furnace.

[0008] As a specific embodiment, in the above production method of chromium-containing hot metal:

[0009] In the batching step, the flux is silica and dolomite, and the chromium-containing pellet ore, coke, silica, and dolomite are weighed and batched according to the following parts by weight:

[0010]

[0011] Among them, in the chrome-containing pellet ore, the TFe is 19.8%, the Cr₂O₃ content is 38.83%, the SiO₂ content is 4.28%, the Al₂O₃ content is 15.38%, and the CaO content is 2.24%; in the silica, the SiO₂ content is 96%; in the dolomite, the MgO content is 18.3% and the CaO content is 31.2%.

[0012] In the feeding step, the chrome-containing pellet ore, coke, silica and dolomite after batching are preheated to 450 °C in a preheating bin and then added into the submerged arc furnace.

[0013] In the smelting step, the volume contents of the submerged arc furnace gas, hydrogen and coalbed methane in the mixed gas are controlled to be 50 - 70% of the submerged arc furnace gas, 30 - 40% of hydrogen, and 1 - 4% of coalbed methane. The mixed gas is heated to 1200 - 1300 °C and then evenly injected into the submerged arc furnace through 8 tuyeres 1 meter below the surface of the charge in the submerged arc furnace. The injection volume of the mixed gas is controlled to be 3000 - 8000 m 3 / h.

[0014] As a specific embodiment, in the above method for producing chrome-containing hot metal, in the smelting step, the volume contents of the submerged arc furnace gas, hydrogen and coalbed methane in the mixed gas are controlled to be 60% of the submerged arc furnace gas, 38% of hydrogen, and 2% of coalbed methane. The mixed gas is heated to 1200 °C and then evenly injected into the submerged arc furnace through 8 tuyeres 1 meter below the surface of the charge in the submerged arc furnace. The injection volume of the mixed gas is controlled to be 4500 m 3 / h.

[0015] As a specific embodiment, in the above method for producing chrome-containing hot metal, in the smelting step, the volume contents of the submerged arc furnace gas, hydrogen and coalbed methane in the mixed gas are controlled to be 60% of the submerged arc furnace gas, 38% of hydrogen, and 2% of coalbed methane. The mixed gas is heated to 1200 °C and then evenly injected into the submerged arc furnace through 8 tuyeres 1 meter below the surface of the charge in the submerged arc furnace. The injection volume of the mixed gas is controlled to be 5000 m 3 / h.

[0016] As a specific embodiment, in the above method for producing chrome-containing hot metal, in the smelting step, the volume contents of the submerged arc furnace gas, hydrogen and coalbed methane in the mixed gas are controlled to be 60% of the submerged arc furnace gas, 38% of hydrogen, and 2% of coalbed methane. The mixed gas is heated to 1200 °C and then evenly injected into the submerged arc furnace through 8 tuyeres 1 meter below the surface of the charge in the submerged arc furnace. The injection volume of the mixed gas is controlled to be 6000 m 3 / h.

[0017] As a specific embodiment, in the above-mentioned production method of chromium-containing hot metal, in the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen, and 2% for coalbed methane. The mixed gas is heated to 1200 °C and then evenly injected into the submerged arc furnace through 8 tuyeres 1 meter below the burden surface of the submerged arc furnace. The injection amount of the mixed gas is controlled to be 7000 m 3 / h.

[0018] As a specific embodiment, in the above-mentioned production method of chromium-containing hot metal, in the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen, and 2% for coalbed methane. The mixed gas is heated to 1280 °C and then evenly injected into the submerged arc furnace through 8 tuyeres 1 meter below the burden surface of the submerged arc furnace. The injection amount of the mixed gas is controlled to be 7000 m 3 / h.

[0019] As a specific embodiment, in the above-mentioned production method of chromium-containing hot metal, in the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 58% for submerged arc furnace gas, 40% for hydrogen, and 2% for coalbed methane. The mixed gas is heated to 1280 °C and then evenly injected into the submerged arc furnace through 8 tuyeres 1 meter below the burden surface of the submerged arc furnace. The injection amount of the mixed gas is controlled to be 7000 m 3 / h.

[0020] The production method of chromium-containing hot metal of the present invention has the following advantages and beneficial effects:

[0021] The chromium-containing hot metal smelted by using the production method of chromium-containing hot metal of the present invention fully meets the production requirements of stainless steel. At the same time, CO in the submerged arc furnace gas can be reused to pre-reduce the burden in the submerged arc furnace, so that the chemical energy of the submerged arc furnace gas is fully utilized. And by pre-reducing the burden with the submerged arc furnace gas, the consumption of coke during the smelting of the submerged arc furnace is significantly reduced, thus achieving the goal of low-carbon smelting. Specific embodiments

[0022] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments and examples of the present invention. Obviously, the described embodiments and examples are only a part of the embodiments and examples of the present invention, rather than all of them. Based on the embodiments and examples of the present invention, all other embodiments and examples obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0023] The production method of chromium-containing hot metal of the present invention includes the following steps:

[0024] (1) Batching: batch ferrochrome pellets, flux, and coke.

[0025] (2) Charging: preheat the batch of ferrochrome pellets, flux, and coke and then add them into the submerged arc furnace from the top of the furnace.

[0026] (3) Smelting: pass an electric current through the electrodes in the submerged arc furnace for smelting. During the smelting process, pre-reduction of the furnace charge is carried out. The pre-reduction of the furnace charge includes: purify the furnace gas discharged from the top of the submerged arc furnace during the smelting process, then mix it with hydrogen and coalbed methane to form a mixture of furnace gas, hydrogen, and coalbed methane. Heat the mixture and then evenly inject it into the submerged arc furnace from the tuyeres below the furnace burden surface to pre-reduce the furnace charge in the submerged arc furnace.

[0027] More specifically, the production method of chromium-containing hot metal of the present invention includes the following steps:

[0028] (1) Batching

[0029] Weigh and batch chromite pellets, coke, and silica and dolomite as flux according to the following weight parts:

[0030]

[0031] Among them, in the chromite pellets, the content of TFe (total iron content) is 19.8%, the content of Cr2O3 is 38.83%, the content of SiO2 is 4.28%, the content of Al2O3 is 15.38%, and the content of CaO is 2.24%; in the silica, the content of SiO2 is 96%; in the dolomite, the content of MgO is 18.3% and the content of CaO is 31.2%.

[0032] (2) Charging

[0033] Preheat the batch of chromite pellets, coke, silica, and dolomite to 450 °C in the preheating bin and then add them into the submerged arc furnace through the batching program.

[0034] (3) Smelting

[0035] Pass an electric current through the three electrodes in the submerged arc furnace for smelting. During the smelting process, pre-reduction of the furnace charge is carried out. The pre-reduction of the furnace charge includes: purify the furnace gas discharged from the top of the submerged arc furnace during the smelting process, then mix it with hydrogen and coalbed methane to form a mixture of furnace gas, hydrogen, and coalbed methane. Then heat the mixture to 1200 - 1300 °C and evenly inject the heated mixture into the submerged arc furnace from 8 tuyeres 1 meter below the furnace burden surface to pre-reduce the furnace charge in the submerged arc furnace. Among them, the volume contents of furnace gas, hydrogen, and coalbed methane in the mixture are controlled to be 50 - 70% for furnace gas, 30 - 40% for hydrogen, and 1 - 4% for coalbed methane, and the injection volume of the mixture is controlled to be 3000 - 8000 m 3 / h.

[0036] Thus, the chromium-containing hot metal is smelted by using the production method of chromium-containing hot metal of the present invention. The chromium content in the chromium-containing hot metal is 51-53%, the silicon content is 3-4%, and the temperature of the chromium-containing hot metal is 1410-1460 °C, which fully meets the production requirements of stainless steel. Moreover, CO in the submerged arc furnace gas can pre-reduce the furnace charge in the submerged arc furnace, so that the chemical energy of the submerged arc furnace gas is fully utilized. And by pre-reducing the furnace charge with the submerged arc furnace gas, the consumption of coke during the smelting of the submerged arc furnace is significantly reduced, thus achieving the goal of low-carbon smelting. Through actual measurement, when using the production method of chromium-containing hot metal of the present invention, the coke consumption required for producing chromium-containing hot metal is 390-450 kg / t, which is significantly lower than the coke consumption of 500 kg / t for submerged arc furnace smelting in the prior art.

[0037] The following uses specific embodiments to illustrate the production method of chromium-containing hot metal of the present invention.

[0038] Comparative Example

[0039] First, a conventional production method for smelting chromium-containing hot metal in a submerged arc furnace in the prior art is provided as a comparative example, and its production steps are as follows:

[0040] (1) Batching

[0041] Weigh and batch the chromium-containing pellet ore, coke, silica stone and dolomite according to the following parts by weight:

[0042]

[0043] Among them, the TFe in the chromium-containing pellet ore is 19.8%, the Cr2O3 content is 38.83%, the SiO2 content is 4.28%, the Al2O3 content is 15.38%, and the CaO content is 2.24%; the SiO2 content in the silica stone is 96%; the MgO content in the dolomite is 18.3%, and the CaO content is 31.2%;

[0044] (2) Charging

[0045] Preheat the chromium-containing pellet ore, coke, silica stone and dolomite after batching to 450 °C in the preheating bin, and add them to the submerged arc furnace through the batching program;

[0046] (3) Smelting

[0047] Pass current through the three electrodes in the submerged arc furnace for smelting to obtain chromium-containing hot metal.

[0048] The chromium content in the chromium-containing hot metal produced by the production method of the comparative example is 51.3%, the silicon content is 3.18%, and the temperature of the chromium-containing hot metal is 1435 °C. Through actual measurement, the coke consumption of the production method of the chromium-containing hot metal in the comparative example is 483 kg / t.

[0049] Example 1

[0050] The production method of the chromium-containing hot metal in Example 1 of the present invention includes the following steps:

[0051] (1) Batching

[0052] Weigh and batch the chromium-containing pellet ore, coke, and silica and dolomite as fluxes according to the following parts by weight:

[0053]

[0054] Among them, TFe in the chromium-containing pellet ore is 19.8%, the Cr2O3 content is 38.83%, the SiO2 content is 4.28%, the Al2O3 content is 15.38%, and the CaO content is 2.24%; the SiO2 content in silica is 96%; the MgO content in dolomite is 18.3%, and the CaO content is 31.2%;

[0055] (2) Charging

[0056] Preheat the chromium-containing pellet ore, coke, silica, and dolomite after batching to 450 °C in a preheating bin, and add them to the submerged arc furnace through a batching program;

[0057] (3) Smelting

[0058] Pass current through the three electrodes in the submerged arc furnace for smelting. During the smelting process, pre-reduction of the furnace charge is carried out. The pre-reduction of the furnace charge includes: after purifying the submerged arc furnace gas discharged from the top of the submerged arc furnace during the smelting process, hydrogen and coalbed methane are added to form a mixture of submerged arc furnace gas, hydrogen, and coalbed methane. The volume contents of submerged arc furnace gas, hydrogen, and coalbed methane in the mixture are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen, and 2% for coalbed methane. Then heat the mixture to 1200 °C and evenly inject the heated mixture into the submerged arc furnace from 8 tuyeres 1 meter below the surface of the furnace charge in the submerged arc furnace. The injection volume of the mixture is controlled to be 4500 m 3 / h to pre-reduce the furnace charge in the submerged arc furnace.

[0059] The chromium-containing hot metal is smelted by using the production method of chromium-containing hot metal in Example 1. The chromium content in this chromium-containing hot metal is 51.8%, the silicon content is 3.6%, and the temperature of this chromium-containing hot metal is 1430 °C, which fully meets the production requirements of stainless steel. Moreover, the coke consumption required for producing the chromium-containing hot metal is reduced to 427 kg / t. It can be seen that by adopting the production method of chromium-containing hot metal in Example 1 of the present invention, when the chromium content, silicon content, and temperature of the chromium-containing hot metal are basically the same, the coke consumption is reduced by 56 kg / t compared with the comparative example of the prior art.

[0060] Example 2

[0061] The production method of chromium-containing hot metal in Example 2 of the present invention includes the following steps:

[0062] (1) Batching

[0063] Weigh and batch the chromium-containing pellet ore, coke, and silica and dolomite as fluxes according to the following parts by weight:

[0064]

[0065] Among them, the TFe in the chromium-containing pellet ore is 19.8%, the Cr2O3 content is 38.83%, the SiO2 content is 4.28%, the Al2O3 content is 15.38%, and the CaO content is 2.24%; the SiO2 content in the silica is 96%; the MgO content in the dolomite is 18.3% and the CaO content is 31.2%;

[0066] (2) Charging

[0067] Preheat the batched chromium-containing pellet ore, coke, silica, and dolomite to 450 °C in a preheating bin, and add them into the submerged arc furnace through a batching program;

[0068] (3) Smelting

[0069] Pass an electric current through the three electrodes in the submerged arc furnace for smelting. During the smelting process, pre-reduction of the furnace charge is carried out. The pre-reduction of the furnace charge includes: after purifying the submerged arc furnace gas discharged from the top of the submerged arc furnace during the smelting process, hydrogen and coalbed methane are added to form a mixture of submerged arc furnace gas, hydrogen, and coalbed methane. The volume contents of submerged arc furnace gas, hydrogen, and coalbed methane in the mixture are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen, and 2% for coalbed methane. Then, heat the mixture to 1200 °C and evenly inject the heated mixture into the submerged arc furnace from 8 tuyeres 1 meter below the furnace burden surface of the submerged arc furnace. The injection amount of the mixture is controlled to be 5000 m 3 / h to pre-reduce the furnace charge in the submerged arc furnace.

[0070] The chromium-containing hot metal is smelted by using the production method of chromium-containing hot metal in Example 2. The chromium content in the chromium-containing hot metal is 51.9%, the silicon content is 3.5%, and the temperature of the chromium-containing hot metal is 1425 °C, which fully meets the production requirements of stainless steel. Moreover, the coke consumption required for producing the chromium-containing hot metal is reduced to 421 kg / t. It can be seen that by using the production method of chromium-containing hot metal in Example 2 of the present invention, when the chromium content, silicon content, and temperature of the chromium-containing hot metal are basically the same, the coke consumption is reduced by 62 kg / t compared with the comparative example of the prior art.

[0071] Example 3

[0072] The production method of chromium-containing hot metal in Example 3 of the present invention includes the following steps:

[0073] (1) Batching

[0074] Weigh and batch the chromium-containing pellet ore, coke, and silica and dolomite as fluxes according to the following parts by weight:

[0075]

[0076] Among them, the TFe in the chromium-containing pellet ore is 19.8%, the Cr₂O₃ content is 38.83%, the SiO₂ content is 4.28%, the Al₂O₃ content is 15.38%, and the CaO content is 2.24%; the SiO₂ content in the silica is 96%; the MgO content in the dolomite is 18.3% and the CaO content is 31.2%;

[0077] (2) Charging

[0078] Preheat the chromium-containing pellet ore, coke, silica, and dolomite after batching to 450 °C in a preheating bin, and add them to the submerged arc furnace through a batching program;

[0079] (3) Smelting

[0080] Pass current through three electrodes in the submerged arc furnace for smelting. During the smelting process, pre-reduction of the furnace charge is carried out. The pre-reduction of the furnace charge includes: after purifying the submerged arc furnace gas discharged from the top of the submerged arc furnace during the smelting process, hydrogen and coalbed methane are added to form a mixture of submerged arc furnace gas, hydrogen, and coalbed methane. The volume contents of submerged arc furnace gas, hydrogen, and coalbed methane in the mixture are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen, and 2% for coalbed methane. Then, heat the mixture to 1200 °C and evenly spray the heated mixture into the submerged arc furnace from 8 tuyeres 1 meter below the furnace burden surface of the submerged arc furnace. The injection volume of the mixture is controlled to be 6000 m 3 / h to pre-reduce the furnace charge in the submerged arc furnace.

[0081] The chromium-containing hot metal is smelted by using the production method of chromium-containing hot metal in Example 3. The chromium content in the chromium-containing hot metal is 52.0%, the silicon content is 3.7%, and the temperature of the chromium-containing hot metal is 1430 °C, which fully meets the production requirements of stainless steel. Moreover, the coke consumption required for producing the chromium-containing hot metal is reduced to 416 kg / t. It can be seen that by adopting the production method of chromium-containing hot metal in Example 3 of the present invention, when the chromium content, silicon content, and temperature of the chromium-containing hot metal are basically the same, the coke consumption is reduced by 67 kg / t compared with the comparative example of the prior art.

[0082] Example 4

[0083] The production method of chromium-containing hot metal in Example 4 of the present invention includes the following steps:

[0084] (1) Batching

[0085] Weigh and batch the chromium-containing pellet ore, coke, and silica and dolomite as fluxes according to the following parts by weight:

[0086]

[0087] Among them, the TFe in the chromium-containing pellet ore is 19.8%, the Cr₂O₃ content is 38.83%, the SiO₂ content is 4.28%, the Al₂O₃ content is 15.38%, and the CaO content is 2.24%; the SiO₂ content in the silica is 96%; the MgO content in the dolomite is 18.3%, and the CaO content is 31.2%;

[0088] (2) Charging

[0089] Preheat the chromium-containing pellet ore, coke, silica, and dolomite after batching to 450 °C in the preheating bin, and add them to the submerged arc furnace through the batching program;

[0090] (3) Smelting

[0091] Pass current through the three electrodes in the submerged arc furnace for smelting. During the smelting process, carry out pre-reduction of the furnace charge. The pre-reduction of the furnace charge includes: after purifying the submerged arc furnace gas discharged from the top of the submerged arc furnace during the smelting process, blending in hydrogen and coalbed methane to form a mixture of submerged arc furnace gas, hydrogen, and coalbed methane. The volume contents of submerged arc furnace gas, hydrogen, and coalbed methane in the mixture are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen, and 2% for coalbed methane. Then heat the mixture to 1200 °C and evenly inject the heated mixture into the submerged arc furnace through 8 tuyeres 1 meter below the surface of the furnace charge in the submerged arc furnace. The injection volume of the mixture is controlled to be 7000 m 3 / h to carry out pre-reduction of the furnace charge in the submerged arc furnace.

[0092] The chromium-containing hot metal is smelted by using the production method of chromium-containing hot metal in Example 4. The chromium content in the chromium-containing hot metal is 52.0%, the silicon content is 3.7%, and the temperature of the chromium-containing hot metal is 1430 °C, fully meeting the production requirements of stainless steel. Moreover, the coke consumption required for producing the chromium-containing hot metal is reduced to 414 kg / t. It can be seen that by adopting the production method of chromium-containing hot metal in Example 4 of the present invention, when the chromium content, silicon content, and temperature of the chromium-containing hot metal are basically the same, the coke consumption is reduced by 69 kg / t compared with the comparative example of the prior art.

[0093] Example 5

[0094] The production method of chromium-containing hot metal in Example 5 of the present invention includes the following steps:

[0095] (1) Batching

[0096] The chromium-containing pellet ore, coke, and silica and dolomite as fluxes are weighed and batched according to the following parts by weight:

[0097]

[0098]

[0099] Among them, TFe in the chromium-containing pellet ore is 19.8%, the Cr2O3 content is 38.83%, the SiO2 content is 4.28%, the Al2O3 content is 15.38%, and the CaO content is 2.24%; the SiO2 content in the silica is 96%; the MgO content in the dolomite is 18.3%, and the CaO content is 31.2%;

[0100] (2) Charging

[0101] The chromium-containing pellet ore, coke, silica, and dolomite after batching are preheated to 450 °C in the preheating bin and added to the submerged arc furnace through the batching program;

[0102] (3) Smelting

[0103] Three electrodes in the submerged arc furnace are energized for smelting. During the smelting process, pre-reduction of the furnace charge is carried out. The pre-reduction of the furnace charge includes: after purifying the submerged arc furnace gas discharged from the top of the submerged arc furnace during the smelting process, hydrogen and coalbed methane are added to form a mixture of submerged arc furnace gas, hydrogen, and coalbed methane. The volume contents of submerged arc furnace gas, hydrogen, and coalbed methane in the mixture are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen, and 2% for coalbed methane. Then the mixture is heated to 1280 °C, and the heated mixture is evenly sprayed into the submerged arc furnace from 8 tuyeres 1 meter below the furnace burden surface of the submerged arc furnace. The injection volume of the mixture is controlled to be 7000 m 3 / h to carry out pre-reduction of the furnace charge in the submerged arc furnace.

[0104] The chromium-containing hot metal is smelted by using the production method of chromium-containing hot metal in Example 5. The chromium content in the chromium-containing hot metal is 52.1%, the silicon content is 3.85%, and the temperature of the chromium-containing hot metal is 1435 °C, which fully meets the production requirements of stainless steel. Moreover, the coke consumption required for producing the chromium-containing hot metal is reduced to 404 kg / t. It can be seen that by adopting the production method of chromium-containing hot metal in Example 5 of the present invention, when the chromium content, silicon content, and temperature of the chromium-containing hot metal are basically the same, the coke consumption is reduced by 79 kg / t compared with the comparative example of the prior art.

[0105] Example 6

[0106] The production method of chromium-containing hot metal in Example 6 of the present invention includes the following steps:

[0107] (1) Batching

[0108] Weigh and batch the chromium-containing pellet ore, coke, and silica and dolomite as fluxes according to the following parts by weight:

[0109]

[0110] Among them, the TFe in the chromium-containing pellet ore is 19.8%, the Cr₂O₃ content is 38.83%, the SiO₂ content is 4.28%, the Al₂O₃ content is 15.38%, and the CaO content is 2.24%; the SiO₂ content in the silica is 96%; the MgO content in the dolomite is 18.3%, and the CaO content is 31.2%;

[0111] (2) Charging

[0112] Preheat the chromium-containing pellet ore, coke, silica, and dolomite after batching to 450 °C in the preheating bin, and add them to the submerged arc furnace through the batching program;

[0113] (3) Smelting

[0114] Pass an electric current through the three electrodes in the submerged arc furnace for smelting. During the smelting process, pre-reduction of the furnace charge is carried out. The pre-reduction of the furnace charge includes: after purifying the submerged arc furnace gas discharged from the top of the submerged arc furnace during the smelting process, hydrogen and coalbed methane are added to form a mixture of submerged arc furnace gas, hydrogen, and coalbed methane. The volume contents of submerged arc furnace gas, hydrogen, and coalbed methane in the mixture are controlled to be 58% for submerged arc furnace gas, 40% for hydrogen, and 2% for coalbed methane. Then, the mixture is heated to 1280 °C, and the heated mixture is evenly injected into the submerged arc furnace from 8 tuyeres 1 meter below the surface of the furnace charge in the submerged arc furnace. The injection amount of the mixture is controlled to be 7000 m 3 / h to pre-reduce the furnace charge in the submerged arc furnace.

[0115] The chromium-containing hot metal is smelted by using the production method of chromium-containing hot metal in Example 6. The chromium content in the chromium-containing hot metal is 51.9%, the silicon content is 3.75%, and the temperature of the chromium-containing hot metal is 1438°C, which fully meets the production requirements of stainless steel. Moreover, the coke consumption required for producing chromium-containing hot metal is reduced to 398 kg / t. It can be seen that by using the production method of chromium-containing hot metal in Example 6 of the present invention, when the chromium content, silicon content, and temperature of the chromium-containing hot metal are basically the same, the coke consumption is reduced by 85 kg / t compared with the comparative example of the prior art.

[0116] In summary, compared with the prior art, the production method of chromium-containing hot metal of the present invention has the following advantages and beneficial effects:

[0117] The chromium-containing hot metal smelted by using the production method of chromium-containing hot metal of the present invention fully meets the production requirements of stainless steel. At the same time, CO in the submerged arc furnace gas can be reused to pre-reduce the burden in the submerged arc furnace, so that the chemical energy of the submerged arc furnace gas is fully utilized. And by pre-reducing the burden with the submerged arc furnace gas, the coke consumption during the smelting of the submerged arc furnace is significantly reduced, thus achieving the goal of low-carbon smelting.

[0118] The above embodiments and examples are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments and examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments and examples, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments and examples of the present invention.

Claims

1. A production method of chromium-containing hot metal, characterized in that, Through the production method of the chromium-containing hot metal, CO in the submerged arc furnace gas can be reused, the burden in the submerged arc furnace can be pre-reduced, and the chemical energy of the submerged arc furnace gas can be fully utilized. By pre-reducing the burden with the submerged arc furnace gas, the consumption of coke during the smelting in the submerged arc furnace is reduced, and low-carbon smelting is achieved. The method includes the following steps: (1) Batching: batch the chromium-iron pellets, flux, and coke; (2) Charging: preheat the batched chromium-iron pellets, flux, and coke and then add them into the submerged arc furnace from the top of the submerged arc furnace; (3) Smelting: pass an electric current through the electrodes in the submerged arc furnace for smelting. During the smelting process, burden pre-reduction is carried out. The burden pre-reduction includes: after purifying the submerged arc furnace gas discharged from the top of the submerged arc furnace during the smelting process, adding hydrogen and coalbed methane, forming a mixture of the submerged arc furnace gas, hydrogen, and coalbed methane, heating the mixture, and then evenly injecting the mixture into the submerged arc furnace from the tuyeres under the burden surface of the submerged arc furnace to pre-reduce the burden in the submerged arc furnace; In the batching step, the flux is silica and dolomite, and the chromium-containing pellet ore, coke, silica, and dolomite are weighed and batched according to the following parts by weight: Among them, in the chromium-containing pellet ore, TFe is 19.8%, the content of Cr2O3 is 38.83%, the content of SiO2 is 4.28%, the content of Al2O3 is 15.38%, and the content of CaO is 2.24%; in the silica, the content of SiO2 is 96%; in the dolomite, the content of MgO is 18.3% and the content of CaO is 31.2%; In the charging step, the batched chromium-containing pellet ore, coke, silica, and dolomite are preheated to 450°C in a preheating bin and then added into the submerged arc furnace; In the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 50-70% for submerged arc furnace gas, 30-40% for hydrogen, and 1-4% for coalbed methane. The mixed gas is heated to 1200-1300 °C and then evenly injected into the submerged arc furnace through 8 tuyeres located 1 meter below the burden surface of the submerged arc furnace. The injection amount of the mixed gas is controlled to be 3000-8000 m 3 / h.

2. The production method of chromium-containing hot metal according to claim 1, characterized in that, In the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 60% of submerged arc furnace gas, 38% of hydrogen and 2% of coalbed methane. The mixed gas is heated to 1200 °C and then evenly injected into the submerged arc furnace through 8 tuyeres located 1 meter below the burden surface of the submerged arc furnace. The injection amount of the mixed gas is controlled to be 4500 m 3 / h.

3. The production method of chromium-containing hot metal according to claim 1, characterized in that, In the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen and 2% for coalbed methane. The mixed gas is heated to 1200 °C and then evenly injected into the submerged arc furnace through 8 tuyeres located 1 meter below the burden surface of the submerged arc furnace. The injection amount of the mixed gas is controlled to be 5000 m 3 / h.

4. The production method of chromium-containing hot metal according to claim 1, characterized in that, In the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen, and 2% for coalbed methane. The mixed gas is heated to 1200 °C and then evenly injected into the submerged arc furnace through 8 tuyeres located 1 meter below the burden surface of the submerged arc furnace. The injection amount of the mixed gas is controlled to be 6000 m 3 / h.

5. The production method of chromium-containing hot metal according to claim 1, characterized in that, In the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen and 2% for coalbed methane. The mixed gas is heated to 1200 °C and then evenly injected into the submerged arc furnace through 8 tuyeres located 1 m below the burden surface of the submerged arc furnace. The injection amount of the mixed gas is controlled to be 7000 m 3 / h.

6. The production method of chromium-containing hot metal according to claim 1, characterized in that, In the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 60% for submerged arc furnace gas, 38% for hydrogen and 2% for coalbed methane. The mixed gas is heated to 1280 °C and then evenly injected into the submerged arc furnace through 8 tuyeres located 1 meter below the burden surface of the submerged arc furnace. The injection volume of the mixed gas is controlled to be 7000 m 3 / h.

7. The production method of the chromium-containing hot metal according to claim 1, characterized in that, In the smelting step, the volume contents of the mixed gas of submerged arc furnace gas, hydrogen and coalbed methane are controlled to be 58% for submerged arc furnace gas, 40% for hydrogen and 2% for coalbed methane. The mixed gas is heated to 1280 °C and then evenly injected into the submerged arc furnace through 8 tuyeres located 1 meter below the burden surface of the submerged arc furnace. The injection amount of the mixed gas is controlled to be 7000 m 3 / h.

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