Method for reducing harmful components in vanadium slag

Abstract

The invention provides a method for reducing harmful components in vanadium slag, which comprises the following steps of: smelting vanadium-containing molten iron in a vanadium extraction converter by adopting a top-bottom combined blowing process in the vanadium extraction converter process to obtain semi-steel and vanadium slag; the top-bottom combined blowing process comprises top blowing of oxygen and bottom blowing of nitrogen; the nitrogen bottom blowing comprises first-stage low bottom blowing stirring, second-stage strong bottom blowing stirring and third-stage high-strength bottom blowing stirring, a coolant is added in the first-stage low bottom blowing stirring and the second-stage strong bottom blowing stirring, and lime is added in the third-stage high-strength bottom blowing stirring. In the blowing process, the coolant is added in the first two stages of nitrogen bottom blowing, the lime is added in the third stage for slag state adjustment, finally, the content of harmful ingredients such as P, Pb and Zn in the vanadium slag is low, follow-up oxidizing roasting and leaching of the vanadium slag are facilitated, and therefore the comprehensive utilization rate of vanadium and the quality of vanadium products are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of steel smelting, and particularly relates to a method for reducing harmful components in vanadium slag. Background Art

[0002] Vanadium is an important strategic resource, and China's vanadium products are mainly obtained through comprehensive utilization of vanadium-titanium magnetite. At present, most steel enterprises obtain vanadium products through the following methods: smelting vanadium-titanium magnetite, the molten iron produced by blast furnace smelting of vanadium-titanium magnetite has a high vanadium content, and vanadium slag is produced by treating the molten iron for vanadium product production. At present, there are many production methods for producing vanadium slag at home and abroad, mainly including the New Zealand ladle blowing vanadium process, the South African rocking ladle vanadium extraction process, the converter vanadium extraction processes in Russia and China, etc. Other vanadium extraction processes also include vanadium extraction from vanadium-containing steel slag, vanadium extraction from stone coal, etc.

[0003] The production process systems of converter vanadium extraction at home and abroad are all continuously improved by adding coolants + process temperature + blowing time. Converter vanadium extraction is an exothermic process. The oxidation of elements such as [Si], [Mn], [V], and [C] causes the molten bath to heat up rapidly. The oxidation of [Si] and [Mn] occurs before the oxidation of [V], and it is impossible to inhibit this reaction during vanadium extraction. The conversion temperature of [C] and [V] is about 1385 °C. Therefore, to obtain a high oxidation rate of [V] and [V] recovery rate, it is necessary to add a vanadium extraction coolant to control the molten bath temperature to approach the conversion temperature of [C] and [V] to achieve the purpose of vanadium extraction and carbon preservation, and reduce [V] to below 0.05%. The end-point semi-steel temperature for vanadium extraction should not be too high. In the early stage of the vanadium extraction process, vanadium oxidation is the main process, and in the later stage, vanadium reduction is the main process, but the vanadium reduction is the main process during the vanadium blowing process. Therefore, when cooling down, coolants are added to reduce the temperature of the molten iron to a suitable range. During converter smelting, the vanadium in the semi-steel is oxidized by controlling the blowing time and process temperature to improve the recovery rate.

[0004] In the actual production process, the quality of vanadium slag is closely related to the vanadium recovery rate of wet vanadium extraction. For example, when the TFe content in vanadium slag is too high, FeO is oxidized to Fe2O3 during the oxidation roasting process of vanadium slag, releasing a large amount of heat, causing the rotary kiln to form rings and affecting production safety. Enterprises often add roasted clinker for heat balance, resulting in energy waste; when the PbO content in vanadium slag increases, the lead content in the roasting leaching solution increases, resulting in a decrease in the vanadium recovery rate in the subsequent process; when the P content in vanadium slag is relatively high, the P content in the roasting leaching solution also increases accordingly, resulting in the phosphorus content of the vanadium product exceeding the standard.

[0005] Chinese Patent No. CN1789435A discloses a vanadium extraction and calcium control coolant for hot metal and a process for vanadium extraction and calcium control from hot metal. The chemical composition (wt%) of the vanadium extraction coolant is as follows: 56 - 60% scale, 30 - 40% iron concentrate powder, and 5 - 10% binder. This coolant can increase the vanadium extraction rate and the grade of vanadium slag, and stabilize the calcium oxide content in the vanadium slag. Chinese Patent No. CN101338351A discloses a vanadium extraction coolant, its preparation method and usage method. This coolant is produced from scale or vanadium extraction sludge, vanadium-bearing iron concentrate, and binder as raw materials, and contains 80% - 95% iron oxide, 3 - 6% SiO2, 0.1 - 0.6% V2O5, and 1 - 3% MgCl2. Chinese Patent No. CN104561427A discloses a method for extracting vanadium from vanadium-bearing hot metal. The vanadium-bearing hot metal is subjected to stirring treatment, with a stirring speed of 50 - 150 r / min, the immersion depth of the stirring head being 200 - 800 mm, and the stirring time being 20 - 40 min; while stirring, iron oxide is injected into the hot metal, with an addition amount of 15 - 50 kg / tFe; after the blowing and stirring are completed, the vanadium slag is removed, and semi-steel is obtained.

[0006] Based on the analysis of the above prior art, there is no report on the method for controlling harmful components in vanadium slag during the converter vanadium extraction process. In order to improve the quality of vanadium products, it is of great significance to provide a method for reducing harmful components in vanadium slag. Summary of the Invention

[0007] The technical problem solved by the present invention is to provide a method for reducing harmful components in vanadium slag. The method provided by this application can make the contents of harmful components such as P, Pb, Zn, etc. in the vanadium slag relatively low, the TFe content relatively low, and the CaO content controllable.

[0008] In view of this, this application provides a method for reducing harmful components in vanadium slag, including:

[0009] Feeding vanadium-bearing hot metal into a converter for vanadium extraction, and during the process of the converter for vanadium extraction, top-bottom combined blowing process is used for blowing to obtain semi-steel and vanadium slag;

[0010] The top-bottom combined blowing process is top blowing oxygen and bottom blowing nitrogen;

[0011] The bottom blowing nitrogen includes a first-stage low bottom blowing and stirring, a second-stage strong bottom blowing and stirring, and a third-stage high-strength bottom blowing and stirring. Cooling agent is added during the first-stage low bottom blowing and stirring and the second-stage strong bottom blowing and stirring, and lime is added during the third-stage high-strength bottom blowing and stirring.

[0012] In some specific embodiments, the gas supply intensity of the top blowing oxygen is 1.0 - 2.0 m 3 / (t·min) -1 , and / or, the gas supply intensity of the bottom blowing nitrogen is 0.1 - 0.2 m3 / (t·min) -1 。

[0013] In some specific embodiments, during the low bottom-blowing stirring in the first stage, when the blowing time is 0 - 2 min, the bottom-blowing nitrogen supply intensity is 0.1 - 0.12 m 3 / (t·min) -1 , and / or, during the strong bottom-blowing stirring in the second stage, when the blowing time is 2 - 4 min, the bottom-blowing nitrogen supply intensity is 0.13 - 0.15 m 3 / (t·min) -1 , and / or, during the high-strength bottom-blowing stirring in the third stage, when the blowing time is 4 - 5 min to the end of blowing, the bottom-blowing nitrogen supply intensity is 0.15 - 0.2 m 3 / (t·min) -1 。

[0014] In some specific embodiments, the total addition amount Q1 of the coolant for the low bottom-blowing stirring in the first stage and the strong bottom-blowing stirring in the second stage is 10 - 50 kg / t of iron.

[0015] In some specific embodiments, the total addition amount Q1 of the coolant for the first stage and the second stage is obtained according to the following formula:

[0016] Q1 = {1360 - T 铁水温度

[0017] + [Si]% × 140 + [Mn]% × 120 + [V]% × 130 + [Ti]% × 110 + ([C]% - 3.4) × 100} ÷ 3.3 (kg / t of iron).

[0018] In some specific embodiments, the addition amount of the coolant for the low bottom-blowing stirring in the first stage is 30 - 50 wt% of the total addition amount of the coolant, and the addition amount of the coolant for the strong bottom-blowing stirring in the second stage is 50 - 70 wt% of the total addition amount of the coolant.

[0019] In some specific embodiments, during the low bottom-blowing stirring in the first stage and the strong bottom-blowing stirring in the second stage, the addition amount of the coolant each time ≤ 1 t, and the coolant is added again 20 - 30 s after each addition of the coolant.

[0020] In some specific embodiments, the coolant is obtained from vanadium extraction dust and / or ironmaking dust.

[0021] In some specific embodiments, the addition amount Q2 of the lime is obtained according to the following formula:

[0022] Q2 = ([Si]% + [Ti]%) × weight of hot metal × 3 kg / furnace.

[0023] In some specific embodiments, after the lime is added, the stirring time of the molten bath is > 1.5 min, and then the oxygen blowing is stopped.

[0024] The present application provides a method for reducing harmful components in vanadium slag. Molten iron containing vanadium is fed into a vanadium extraction converter, and in the process of the vanadium extraction converter, top-bottom combined blowing process is used for blowing. Further, the bottom blowing nitrogen in the top-bottom combined blowing process includes a first-stage low bottom blowing stirring, a second-stage strong bottom blowing stirring, and a third-stage high-strength bottom blowing stirring, and a coolant is added in the first two stages, and lime is added in the third stage; in the above process of the vanadium extraction converter, the coolant is added in the first stage and the second stage to control the temperature of the molten bath, ensure the full oxidation of vanadium, and the addition of lime in the third stage reduces the melting point of the vanadium slag, thereby promoting the full volatilization of harmful components in the vanadium slag, and finally reducing the content of harmful components in the vanadium slag. Specific embodiments

[0025] In order to further understand the present invention, the following describes the preferred implementation modes of the present invention in combination with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0026] In view of the problem that the content of harmful components in vanadium slag produced by vanadium extraction converters in the prior art is relatively high, the present application provides a method for reducing harmful components in vanadium slag. During the blowing process, a vanadium extraction coolant is added in the first two stages of bottom blowing nitrogen, and lime is added in the third stage for slag state adjustment. Finally, the contents of harmful components such as P, Pb, and Zn in the vanadium slag are relatively low, the CaO content is controllable, and the TFe content is relatively low, which is beneficial to the subsequent oxidative roasting and leaching of vanadium slag, thereby being beneficial to improving the comprehensive utilization rate of vanadium and the quality of vanadium products. Specifically, the embodiments of the present invention disclose a method for reducing harmful components in vanadium slag, including:

[0027] Feeding molten iron containing vanadium into a vanadium extraction converter, and in the process of the vanadium extraction converter, using a top-bottom combined blowing process for blowing to obtain semi-steel and vanadium slag;

[0028] The top-bottom combined blowing process is top blowing oxygen and bottom blowing nitrogen;

[0029] The bottom blowing nitrogen includes a first-stage low bottom blowing stirring, a second-stage strong bottom blowing stirring, and a third-stage high-strength bottom blowing stirring. A coolant is added in the first-stage low bottom blowing stirring and the second-stage strong bottom blowing stirring, and lime is added in the third-stage high-strength bottom blowing stirring.

[0030] In the method for reducing harmful components of vanadium slag provided in this application, the vanadium-containing hot metal is fed into a vanadium extraction converter. The vanadium extraction converter is a metallurgical process for extracting vanadium from vanadium-containing hot metal. It selectively oxidizes vanadium in the hot metal and enriches it into the slag through blowing, thereby separating vanadium and iron. The vanadium-containing hot metal comes from a blast furnace using vanadium-titanium magnetite for smelting, where the carbon content is not less than 3.6 wt%, the vanadium content is not less than 0.20 wt%, and the titanium content is not less than 0.10 wt%. In this application, the blowing of the vanadium extraction converter adopts a top-bottom combined blowing process to obtain semi-steel and vanadium slag.

[0031] Specifically, the top-bottom combined blowing process is a process means of top-blowing oxygen and bottom-blowing nitrogen. Among them, top-blowing oxygen is a process of inserting an oxygen lance from the top of the converter and spraying oxygen at high speed onto the surface of the molten bath, which can achieve the selective oxidation of vanadium in the vanadium-containing hot metal. The gas supply intensity of the top-blowing oxygen is 1.0 - 2.0 m 3 / (t·min) -1 Specifically, the gas supply intensity of the top-blowing oxygen is 1.2 - 1.7 m 3 / (t·min) -1 More specifically, the gas supply intensity of the top-blowing oxygen is 1.4 - 1.6 m 3 / (t·min) -1 .

[0032] In this application, the gas supply intensity of the bottom-blowing nitrogen in the top-bottom combined blowing process is 0.1 - 0.2 m 3 / (t·min) -1 ; Further, the bottom-blowing nitrogen includes a first-stage low bottom-blowing stirring, a second-stage strong bottom-blowing stirring, and a third-stage high-strength bottom-blowing stirring. The first-stage low bottom-blowing stirring is that when blowing for 0 - 2 min, the gas supply intensity of the bottom-blowing nitrogen is 0.1 - 0.12 m 3 / (t·min) -1 The second-stage strong bottom-blowing stirring is that when blowing for 2 - 4 min, the gas supply intensity of the bottom-blowing nitrogen is 0.13 - 0.15 m 3 / (t·min) -1 The third-stage high-strength bottom-blowing stirring is that when blowing from 4 - 5 min to the end of blowing, the gas supply intensity of the bottom-blowing nitrogen is 0.15 - 0.2 m 3 / (t·min) -1 ; Specifically, the gas supply intensity of the first-stage low bottom-blowing stirring is 0.1 m 3 / (t·min) -1 、0.11 m 3 / (t·min) -1 、0.12 m 3 / (t·min) -1 The gas supply intensity of the second-stage strong bottom-blowing stirring is 0.13 m3 / (t·min) -1 、 0.14 m 3 / (t·min) -1 、 0.15 m 3 / (t·min) -1 , the gas supply intensity of the high-intensity bottom blowing stirring in the third stage is 0.15 m 3 / (t·min) -1 、 0.16 m 3 / (t·min) -1 、 0.17 m 3 / (t·min) -1 、 0.18 m 3 / (t·min) -1 、 0.19 m 3 / (t·min) -1 、 0.20 m 3 / (t·min) -1 。 In the above first-stage low bottom blowing stirring, low-intensity bottom blowing is adopted to ensure that the carbon burn loss is not too large. In the second-stage strong bottom blowing stirring and the third-stage high bottom blowing stirring, the bottom blowing intensity is increased to strengthen the silicon stirring, promote mass transfer, increase the vanadium oxidation rate, and promote the full melting of the slag materials.

[0033] In the three stages of bottom blowing nitrogen above, the total addition amount Q1 of the coolant in the first-stage low bottom blowing stirring and the second-stage strong bottom blowing stirring is 10 - 50 kg / t of iron. Specifically, the total addition amount Q1 of the coolant in the first-stage low bottom blowing stirring and the second-stage strong bottom blowing stirring is 12 - 47 g / t of iron. More specifically, the total addition amount Q1 of the coolant in the first-stage low bottom blowing stirring and the second-stage strong bottom blowing stirring is 15 - 42 g / t of iron. More specifically, the total addition amount Q1 of the coolant in the first-stage low bottom blowing stirring and the second-stage strong bottom blowing stirring is 20 - 35 g / t of iron.

[0034] In some specific embodiments, the total addition amount Q1 of the coolant is obtained according to the following formula:

[0035] Q1 = {1360 - T 铁水温度

[0036] + [Si]% × 140 + [Mn]% × 120 + [V]% × 130 + [Ti]% × 110 + ([C]% - 3.4) × 100} ÷ 3.3 (kg / t of iron).

[0037] Among them, [Si]% is the mass percentage of Si in the vanadium-containing hot metal, [Mn]% is the mass percentage of Mn in the vanadium-containing hot metal, [Ti]% is the mass percentage of Ti in the vanadium-containing hot metal, and [C]% is the mass percentage of C in the vanadium-containing hot metal.

[0038] The total amount of coolant added can be accurately calculated according to the above calculation formula.

[0039] In this application, the amount of coolant added in the first-stage low bottom-blowing stirring is 30-50% of the total amount of coolant added, and the amount of coolant added in the second-stage strong bottom-blowing stirring is 50-70% of the total amount of coolant added; in some specific embodiments, the amount of coolant added in the first-stage low bottom-blowing stirring is 40% of the total amount of coolant added, and the amount of coolant added in the second-stage strong bottom-blowing stirring is 60% of the total amount of coolant added; further, in the above first-stage low bottom-blowing stirring and second-stage high bottom-blowing stirring, the coolant is also added in batches, that is, the amount of coolant added each time ≤ 1t, and after adding the coolant each time, a reaction time of 20s must be ensured before adding the coolant again until the end of the second-stage high bottom-blowing stirring. The coolant is added in batches in the first-stage low bottom-blowing stirring and the second-stage strong bottom-blowing stirring to ensure that the furnace temperature does not drop too fast and is also conducive to the full melting of the coolant.

[0040] The above coolant in this application is a coolant well-known to those skilled in the art, and this application does not impose special restrictions on it. In specific embodiments, the coolant is obtained from vanadium extraction dust and / or ironmaking dust. Specifically, the coolant is obtained from vanadium extraction dust or ironmaking dust. Both the vanadium extraction dust and the ironmaking dust are mainly composed of iron oxides, with TFe greater than 60%. The coolant is obtained according to the methods well-known to those skilled in the art, and this application has no special restrictions.

[0041] Lime is added in the above-stage high-strength bottom-blowing stirring. Lime is added in this stage to lower the melting point of vanadium slag, promote the mass transfer rate of harmful components in the slag to increase, and thus promote the full volatilization of harmful components; for those skilled in the art, lime is not added during the process of the vanadium extraction converter because it is difficult to control the amount and timing of lime addition, and there is a risk of an increase in P in the vanadium slag after adding lime. In this application, lime is added in this stage and the addition amount of lime is controlled to ensure that CaO meets the national standard requirements in the vanadium slag while promoting the volatilization of harmful components. The addition amount Q2 of the lime is obtained according to the following formula:

[0042] Q2 = ([Si]% + [Ti]%) × weight of hot metal × 3 kg / furnace;

[0043] Among them, [Si]% is the mass percentage of Si in the vanadium-bearing hot metal, [Ti]% is the mass percentage of Ti in the vanadium-bearing hot metal, and the weight unit of the hot metal is ton (t).

[0044] In this application, when the stirring time of the lime added to the molten bath > 1.5 min, the oxygen blowing is stopped and the blowing is ended.

[0045] After the above blowing, first tap half of the molten steel into the ladle and transport it to the steelmaking converter for steelmaking, and then tap the vanadium slag into the slag pot and send it to the vanadium plant for vanadium product production.

[0046] The present application provides a method for reducing harmful components in vanadium slag. During the blowing process, the coolant is added in multiple batches in the first two stages, and lime is added in the third stage for slag state adjustment. The combination of this method reduces harmful components such as P and Pb in the vanadium slag and reduces the content of TFe, making the obtained vanadium slag conducive to subsequent oxidative roasting and leaching, and ultimately conducive to the improvement of the comprehensive utilization rate of vanadium and the quality of vanadium products.

[0047] To further understand the present invention, the following describes in detail the method for reducing harmful components in vanadium slag provided by the present invention in conjunction with embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0048] Example 1

[0049] Produce vanadium extraction coolant using vanadium extraction dust and ash; perform top and bottom combined blowing process on 80t hot metal from the vanadium extraction converter (the relevant parameters are shown in Table 1), and control the oxygen supply intensity of top blowing at 1.0 m 3 / (t·min) -1 ; After charging the hot metal into the converter, lower the oxygen lance for blowing. The blowing is divided into three stages: in the first stage, low bottom blowing stirring, that is, when blowing for 0 - 2 min, control the nitrogen supply intensity of bottom blowing at 0.1 m 3 / (t·min) -1 ; In the second stage, strong bottom blowing stirring, that is, when blowing for 2 - 4 min, control the nitrogen supply intensity of bottom blowing at 0.15 m 3 / (t·min) -1 ; In the third stage, high-strength bottom blowing stirring, that is, when blowing from 4 min to the end of blowing, control the nitrogen supply intensity of bottom blowing at 0.2 m 3 / (t·min) -1 ;

[0050] Table 1 Parameter data table of the above hot metal from the vanadium extraction converter

[0051] Group Hot metal temperature / ℃ Si / % Mn / % V / ％ Ti / % C / ％ Data 1313 0.15 0.21 0.32 0.12 4.12

[0052] The dosages of the coolant and lime are obtained according to the calculation formula in the specification and applied to the following process; the vanadium extraction coolant is added in the first and second stages of the above blowing. The dosage of the vanadium extraction coolant is controlled according to 66.67 kg / t of iron. 40% of the total coolant is added in the first stage of blowing, and 60% of the total coolant is added in the second stage. The amount of coolant added each time ≤ 1 t. After each addition of the coolant, a reaction time of 20 s must be ensured before continuing to add the coolant; 64.8 kg / furnace of lime is added in the third stage of blowing for slag state adjustment. After the lime is added, the molten bath must be stirred for more than 1.5 min before stopping oxygen blowing. After blowing, semi-steel and vanadium slag are obtained. The vanadium slag contains 4.2 wt% CaO, 29.8 wt% TFe, 0.05 wt% P, 0.0010 wt% Pb, and 0.0004 wt% ZnO.

[0053] Example 2

[0054] The vanadium extraction coolant is produced using vanadium extraction dust; 200 t of hot metal from a vanadium extraction converter (the relevant parameters are shown in Table 2) is subjected to a top and bottom combined blowing process. The oxygen supply intensity of the top blowing is controlled at 2.0 m 3 / (t·min) -1 ; After the converter is charged with hot metal, the oxygen lance is lowered for blowing. The blowing is divided into three stages: in the first stage, low bottom blowing stirring is carried out, that is, when blowing for 0 - 2 min, the nitrogen supply intensity of the bottom blowing is controlled at 0.12 m 3 / (t·min) -1 ; In the second stage, strong bottom blowing stirring is carried out, that is, when blowing for 2 - 4 min, the nitrogen supply intensity of the bottom blowing is controlled at 0.13 m 3 / (t·min) -1 ; In the third stage, high-strength bottom blowing stirring is carried out, that is, when blowing from 4 min to the end of blowing, the nitrogen supply intensity of the bottom blowing is controlled at 0.2 m 3 / (t·min) -1 ;

[0055] Table 2 Parameter data table of the above hot metal from the vanadium extraction converter

[0056] Group Hot metal temperature / ℃ Si / % Mn / % V / ％ Ti / % C / ％ Data 1320 0.13 0.23 0.3 0.16 4.26

[0057] The dosages of the coolant and lime are obtained according to the calculation formula in the specification and applied to the following process;

[0058] During the first and second stages of the above smelting process, vanadium extraction coolants are added. The dosage of the vanadium extraction coolants is controlled at 69.21 kg / t of iron. 40% of the total coolant is added in the first stage of smelting, and 60% of the total coolant is added in the second stage. The amount of coolant added each time ≤ 1 t. After each addition of the coolant, a reaction time of 20 s must be ensured before continuing to add the coolant; in the third stage of smelting, 174.0 kg / furnace of lime is added for slag state adjustment. After the lime is added, the molten bath must be stirred for more than 1.5 min before stopping oxygen blowing. After smelting, semi-steel and vanadium slag are obtained. In the vanadium slag, CaO is 5.1 wt%, TFe is 28.10 wt%, P is 0.06 wt%, Pb is 0.0008 wt%, and ZnO is 0.0006 wt%.

[0059] Example 3

[0060] Vanadium extraction coolants are produced using vanadium extraction dust and ash; 140 t of hot metal from a vanadium extraction converter is subjected to top and bottom combined blowing process. The oxygen supply intensity of top blowing is controlled at 1.2 m 3 / (t·min) -1 ; After the converter is charged with hot metal, the oxygen lance is lowered for smelting. The smelting is divided into three stages: In the first stage, low-intensity bottom blowing stirring is carried out, that is, when smelting for 0 - 2 min, the nitrogen supply intensity of bottom blowing is controlled at 0.11 m 3 / (t·min) -1 ; In the second stage, strong bottom blowing stirring is carried out, that is, when smelting for 2 - 4 min, the nitrogen supply intensity of bottom blowing is controlled at 0.14 m 3 / (t·min) -1 ; In the third stage, high-intensity bottom blowing stirring is carried out, that is, when smelting from 4 min to the end of smelting, the nitrogen supply intensity of bottom blowing is controlled at 0.18 m 3 / (t·min) -1 ;

[0061] Table 3 Parameter data table of the above hot metal from the vanadium extraction converter

[0062] Group Hot metal temperature / ℃ Si / % Mn / % V / ％ Ti / % C / ％ Data 1290 0.16 0.26 0.33 0.11 4.32

[0063] The dosages of the coolant and lime are obtained according to the calculation formula in the specification and applied to the following process; the vanadium extraction coolant is added in the first stage and the second stage of the above blowing. The dosage of the vanadium extraction coolant is controlled according to 821 kg / t of iron. In the first stage of blowing, it is added according to 40% of the total coolant, and in the second stage, it is added according to 60% of the total coolant. The dosage of each addition of the coolant ≤ 1 t. After each addition of the coolant, a reaction time of 20 s must be ensured before the coolant can be added continuously; in the third stage of blowing, 113.4 kg / furnace of lime is added for slag state adjustment. After the lime is added, the molten bath must be stirred for more than 1.5 min before the oxygen blowing can be stopped. After blowing, semi-steel and vanadium slag are obtained, in which the vanadium slag contains 4.0 wt% CaO, 30.1 wt% TFe, 0.05 wt% P, 0.0014 wt% Pb, and 0.0008 wt% ZnO0.

[0064] Control example

[0065] The vanadium extraction coolant is produced by using vanadium extraction dust; 80 t of hot metal from a vanadium extraction converter (the relevant parameters are shown in Table 4) is subjected to top and bottom combined blowing process, and the oxygen supply intensity of top blowing is controlled at 1.1 m 3 / (t·min) -1 ; After the converter is charged with hot metal, the oxygen lance is lowered for blowing. The blowing is divided into three stages: in the first stage, low bottom blowing and stirring, that is, when blowing for 0 - 2 min, the nitrogen supply intensity of bottom blowing is controlled at 0.12 m 3 / (t·min) -1 ; In the second stage, strong bottom blowing and stirring, that is, when blowing for 2 - 4 min, the nitrogen supply intensity of bottom blowing is controlled at 0.14 m 3 / (t·min) -1 ; In the third stage, high-strength bottom blowing and stirring, that is, when blowing from 4 min to the end of blowing, the nitrogen supply intensity of bottom blowing is controlled at 0.16 m 3 / (t·min) -1 ;

[0066] Table 4 Parameter data table of the above hot metal from the vanadium extraction converter

[0067] Hot metal temperature / ℃ Si / % Mn / % V / ％ Ti / % C / ％ Data 1306 0.19 0.2 0.31 0.17 4.19

[0068] The dosage of the coolant is obtained according to the calculation formula in the specification and applied to the following process;

[0069] During the first and second stages of the above smelting process, vanadium extraction coolants are added. The dosage of the vanadium extraction coolants is controlled according to 73.52 kg / t of iron. In the first stage of smelting, 40% of the total coolant is added, and in the second stage, 60% of the total coolant is added. The amount of coolant added each time ≤ 1 t. After each addition of the coolant, a reaction time of 20 s must be ensured before continuing to add the coolant. After smelting, semi-steel and vanadium slag are obtained. In the vanadium slag, CaO is 2.2 wt%, TFe is 32.14 wt%, P is 0.05 wt%, Pb is 0.024 wt%, and ZnO is 0.04 wt%.

[0070] According to the compositions of the vanadium slag in the above Examples 1 to 3, it can be seen that the staged addition of the coolant and lime during the smelting process enables the CaO content in the vanadium slag to be controllable, the harmful components such as phosphorus and lead to be relatively low, and the content of TFe to be relatively low.

[0071] The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0072] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for reducing harmful components in vanadium slag, comprising: Fe-containing hot metal is fed into a vanadium extraction converter, and top-bottom combined blowing process is adopted for blowing during the process of the vanadium extraction converter to obtain semi-steel and vanadium slag; The top-bottom combined blowing process is top blowing oxygen and bottom blowing nitrogen; The bottom blowing nitrogen includes a first-stage low bottom blowing stirring, a second-stage strong bottom blowing stirring and a third-stage high-strength bottom blowing stirring. A coolant is added during the first-stage low bottom blowing stirring and the second-stage strong bottom blowing stirring, and lime is added during the third-stage high-strength bottom blowing stirring.

2. The method according to claim 1, wherein The supply intensity of the top-blown oxygen is 1.0 to 2.0 m 3 / (t·min) -1 , and / or the supply intensity of the bottom-blown nitrogen is 0.1 to 0.2 m 3 / (t·min) -1 .

3. The method according to claim 1 or 2, characterized in that, The low bottom-blowing stirring in the first stage is that when blowing is carried out for 0 - 2 minutes, the bottom-blowing nitrogen gas supply intensity is 0.1 - 0.12 m 3 / (t·min) -1 , and / or, the strong bottom-blowing stirring in the second stage is that when blowing is carried out for 2 - 4 minutes, the bottom-blowing nitrogen gas supply intensity is 0.13 - 0.15 m 3 / (t·min) -1 , and / or, the high-strength bottom-blowing stirring in the third stage is that when blowing is carried out from 4 - 5 minutes to the end of blowing, the bottom-blowing nitrogen gas supply intensity is 0.15 - 0.2 m 3 / (t·min) -1 .

4. The method according to claim 3, characterized in that, The total addition amount Q1 of the coolant during the first-stage low bottom blowing stirring and the second-stage strong bottom blowing stirring is 10-50 kg / t of iron.

5. The method according to claim 4, characterized in that, The total addition amount Q1 of the coolant in the first stage and the second stage is obtained according to the following formula: Q1 = {1360 - T 铁水温度 + %[Si] × 140 + %[Mn] × 120 + %[V] × 130 + %[Ti] × 110 + (%[C] - 3.4) × 100} ÷ 3.3 (kg / t of iron).

6. The method according to claim 4 or 5, characterized in that, The addition amount of the coolant during the first-stage low bottom blowing stirring is 30-50 wt% of the total addition amount of the coolant, and the addition amount of the coolant during the second-stage strong bottom blowing stirring is 50-70 wt% of the total addition amount of the coolant.

7. The method according to claim 6, wherein During the first-stage low bottom blowing stirring and the second-stage strong bottom blowing stirring, the addition amount of the coolant each time ≤ 1 t, and the coolant is added again 20-30 s after each addition of the coolant.

8. The method according to claim 1 or 7, characterized in that, The coolant is obtained from vanadium extraction dedusting ash and / or ironmaking dedusting ash.

9. The method according to claim 1 or 7, characterized in that The addition amount Q2 of the lime is obtained according to the following formula: Q2 = ([Si]% + [Ti]%) × weight of hot metal × 3 kg / furnace.

10. The method according to claim 9, characterized in that, After the lime is added, the oxygen blowing is stopped after the molten pool stirring time > 1.5 min.