阅读说明：本技术 一种富钒渣冶炼生产氮化硅钒的方法 (Method for producing silicon vanadium nitride by smelting vanadium-rich slag ) 是由 吕韬 李秦灿 于洪翔 于 2020-05-21 设计创作，主要内容包括：本发明提供了一种氮化硅钒的生产方法,包括如下步骤：(1)富钒渣、硅石、焦炭、生石灰按预设重量比混合,然后冶炼得到硅钒合金；(2)将所述硅钒合金破碎至20mm以下,然后球磨为-100目的粉料；(3)向所述粉料中加入粘结剂,混合均匀,然后压制成型、烘干得到物料；(4)对所述物料进行真空脱碳、渗氮处理,然后冷却得到氮化硅钒。本发明的方法直接通过火法的方式将富钒渣冶炼成氮化硅钒,省去了湿法环节,流程大大简化,生产效率提高,具有显著的经济效益。(The invention provides a production method of silicon vanadium nitride, which comprises the following steps: (1) mixing vanadium-rich slag, silica, coke and quicklime according to a preset weight ratio, and then smelting to obtain a silicon-vanadium alloy; (2) crushing the silicon-vanadium alloy to be less than 20mm, and then ball-milling the crushed silicon-vanadium alloy into powder of-100 meshes; (3) adding a binder into the powder, uniformly mixing, then performing compression molding and drying to obtain a material; (4) and carrying out vacuum decarburization and nitridation treatment on the material, and then cooling to obtain silicon vanadium nitride. The method directly smelts the vanadium-rich slag into the silicon vanadium nitride in a pyrogenic process mode, thereby saving the wet process link, greatly simplifying the flow, improving the production efficiency and having obvious economic benefit.)

1. The production method of vanadium silicon nitride is characterized by comprising the following steps:

(1) mixing vanadium-rich slag, silica, coke and quicklime according to a preset weight ratio, and then smelting to obtain a silicon-vanadium alloy;

(2) crushing the silicon-vanadium alloy to be less than 20mm, and then ball-milling the crushed silicon-vanadium alloy into powder of-100 meshes;

(3) adding a binder into the powder, uniformly mixing, then performing compression molding and drying to obtain a material;

(4) and carrying out vacuum decarburization and nitridation treatment on the material, and then cooling to obtain silicon vanadium nitride.

2. The production method of vanadium silicon nitride according to claim 1, wherein in the step (1), the preset weight ratio of vanadium-rich slag, silica, coke and quicklime is 24.29-44.35: 2.86-14.65: 7.13-12.16: 41.02-50.75.

3. The production method of vanadium silicon nitride according to claim 1, wherein in the step (2), the vanadium silicon alloy is crushed to a size of 20mm or less, subjected to primary ball milling to a size of-100 meshes, subjected to oxidizing roasting at 600 to 800 ℃ for 4 to 6 hours, and subjected to secondary ball milling to a size of-100 meshes.

4. The method for producing vanadium silicon nitride according to claim 1, wherein in the step (3), the binder is any one or more of water glass, polyvinyl alcohol and cellulose.

5. The method for producing vanadium silicon nitride according to claim 1, wherein in the step (3), the binder accounts for 3 to 6% by weight of the total composition.

6. The method for producing vanadium silicon nitride according to claim 1, wherein in the step (3), the press molding is performed at 12 to 18 Mpa.

7. The method for producing vanadium silicon nitride according to claim 1, wherein in the step (4), the temperature of the vacuum decarburization is 1250 to 1450 ℃, the pressure is 1 to 10Pa, and the vacuum decarburization is maintained for 6 to 10 hours.

8. The method for producing vanadium silicon nitride according to claim 1, wherein in the step (4), the nitriding treatment is performed at a temperature of 1000 to 1150 ℃ and a pressure of 80kPa to 0.1MPa for 12 to 15 hours.

9. The vanadium silicon nitride is characterized by being prepared by the production method of vanadium silicon nitride according to any one of claims 1 to 8.

10. The vanadium silicon nitride according to claim 9, wherein the vanadium silicon nitride comprises, in weight percent, Fe 44.15-55.38%, C0.14-0.45%, Si 6.67-33.01%, V5.85-23.04%, and N7.60-14.54%.

Technical Field

The invention relates to the field of ferroalloy preparation, in particular to a method for producing silicon vanadium nitride by smelting vanadium-rich slag.

Background

Nitrogen has the functions of solid solution strengthening and aging precipitation strengthening in steel, and can form nitrides with alloy elements such as V, Ti, Cr and the like in the steel, so that the strength, the hardness, the wear resistance, the corrosion resistance and the like of the steel are improved. Therefore, the nitrided alloy is used for the production of various steel grades such as heat-resistant steel, corrosion-resistant steel, non-magnetic steel, and the like, and is widely used in the steel industry.

In the text of the annual report (2012) on the comprehensive utilization of Chinese resources, the comprehensive utilization of rare metals such as vanadium in semi-crude metals in the development and utilization of vanadium-titanium resources and the comprehensive utilization of mineral resources is mentioned, and the development of vanadium resources is highly emphasized. The vanadium-rich slag is an important vanadium resource and is usually obtained by smelting vanadium-titanium magnetite in a blast furnace and carrying out oxidation in a converter to extract vanadium.

At present, the utilization of vanadium-rich slag resources is mainly to prepare vanadium tablets (V) by a wet process consisting of the working procedures of salt roasting-leaching-vanadium precipitation-melting and the like₂O₅) And then vanadium series alloys such as ferrovanadium, silicon vanadium nitride, vanadium nitride and the like are prepared from the vanadium sheet through a series of pyrogenic process procedures. The vanadium extraction method has the advantages of long process, low production efficiency, environmental pollution in the wet process, low conversion rate and the like.

The Chinese patent application CN 104388679A discloses a method for extracting vanadium from a vanadium-containing raw material, which extracts vanadium from steel slag and vanadium slag by a sulfuric acid/sulfate wet roasting method; the Chinese patent application CN 105018828A discloses a method for preparing a ferrovanadium alloy, which takes vanadium-containing oxide as a raw material (wherein, the main component of a vanadium sheet is V)₂O₅Included therein), ferrovanadium is produced by a thermite process; the Chinese patent application CN103526098A discloses a silicon nitride ferrovanadium alloy and a production method thereof, wherein the silicon nitride ferrovanadium alloy is prepared by crushing the silicon ferrovanadium alloy serving as a raw material and feeding the crushed silicon ferrovanadium alloy into a high-pressure reactor for vacuum nitriding. However, the methods disclosed in these patent applications do not effectively solve the problems of the existing vanadium extraction process for vanadium-rich slag, such as redundancy, low production efficiency, low conversion rate and environmental pollution.

Disclosure of Invention

In view of the above, the present invention has been made to provide a method for producing vanadium silicon nitride by smelting vanadium-rich slag that overcomes or at least partially solves the above-mentioned problems.

Specifically, the invention is realized by the following technical scheme:

in one aspect, the invention provides a production method of silicon vanadium nitride, which comprises the following steps:

(1) mixing vanadium-rich slag, silica, coke and quicklime according to a preset weight ratio, and then smelting to obtain a silicon-vanadium alloy;

(2) crushing the silicon-vanadium alloy to be less than 20mm, and then ball-milling the crushed silicon-vanadium alloy into powder of-100 meshes;

(3) adding a binder into the powder, uniformly mixing, then performing compression molding and drying to obtain a material;

(4) and carrying out vacuum decarburization and nitridation treatment on the material, and then cooling to obtain silicon vanadium nitride.

Further, in the step (1), the preset weight ratio is that the weight ratio of the vanadium-rich slag, the silica, the coke and the quicklime is 24.29-44.35: 2.86-14.65: 7.13-12.16: 41.02-50.75.

Further, in the step (2), the silicon-vanadium alloy is crushed to be less than 20mm, subjected to primary ball milling to be minus 100 meshes, subjected to oxidizing roasting at 600-800 ℃ for 4-6 hours, and subjected to secondary ball milling to be minus 100 meshes.

Further, in the step (3), the binder is any one or more of water glass, polyvinyl alcohol and cellulose.

Further, in the step (3), the binder accounts for 3-6% by weight of the total mixed material.

Further, in the step (3), the compression molding is carried out at 12-18 MPa.

Further, in the step (4), the temperature of the vacuum decarburization is 1250-1450 ℃, the pressure is 1-10 Pa, and the vacuum decarburization is kept for 6-10 hours.

Further, in the step (4), the nitriding treatment is carried out at a temperature of 1000-1150 ℃ and a pressure of 80 kPa-0.1 MPa for 12-15 hours.

On the other hand, the invention provides silicon vanadium nitride, which is prepared by the production method of silicon vanadium nitride.

Further, the silicon vanadium nitride comprises, by weight, Fe 44.15-55.38%, C0.14-0.45%, Si 6.67-33.01%, V5.85-23.04%, and N7.60-14.54%.

Compared with the prior art, the technical scheme of the invention at least has the following beneficial effects:

according to the method for producing silicon vanadium nitride by smelting vanadium-rich slag, the vanadium-rich slag is directly smelted into the silicon vanadium nitride by a pyrogenic process, so that a wet process link is omitted, the process is greatly simplified, the production efficiency is improved, and the method has remarkable economic benefit.

Detailed Description

The present invention will be described in detail with reference to the following embodiments in order to fully understand the objects, features and effects of the invention, but the present invention is not limited thereto. The process of the present invention employs conventional methods or apparatus in the art, except as described below.

In the present invention, "%" means "% by weight" unless otherwise specified.

The vanadium-rich slag is vanadium slag formed by smelting vanadium-titanium magnetite in a blast furnace to obtain vanadium-containing molten iron and then extracting vanadium by blowing oxygen in a converter for enrichment. Generally, the vanadium-rich slag contains FeO, CaO and SiO₂，MgO，Al₂O₃，V₂O₅These several components, among which the most important V₂O₅The content is mainly in the range of 14-20%. Thus, V₂O₅The vanadium-rich slag with the content of 14-20% can be used in the method.

The utilization of vanadium-rich slag resources at present has the problems of long flow, low production efficiency, environmental pollution, low conversion rate and the like. In view of these problems, the inventors of the present invention have creatively proposed a method for producing vanadium silicon nitride by smelting vanadium-rich slag through research. According to the method, the vanadium-rich slag is directly smelted into the silicon vanadium nitride by a pyrogenic process, so that a wet process link is omitted, the flow is greatly simplified, the production efficiency is improved, and the method has obvious economic benefits and demonstration significance.

The method for smelting the vanadium-rich slag to produce silicon vanadium nitride comprises the following steps: (1) mixing vanadium-rich slag, silica, coke and quicklime according to a preset weight ratio, and then smelting to obtain a silicon-vanadium alloy; (2) crushing the silicon-vanadium alloy to be less than 20mm, and then ball-milling the crushed silicon-vanadium alloy into powder of-100 meshes; (3) adding a binder into the powder, uniformly mixing, then performing compression molding and drying to obtain a material; (4) and carrying out vacuum decarburization and nitridation treatment on the material, and then cooling to obtain silicon vanadium nitride.

In a preferred embodiment, the method for smelting the vanadium-rich slag to produce the silicon-vanadium nitride comprises the following steps:

(1) mixing and smelting raw materials to obtain silicon-vanadium alloy

Vanadium-rich slag, silica, coke and quicklime in a proportion of 24.29-44.35: 2.86-14.65: 7.13-12.16: and 41.02-50.75, and smelting in a submerged arc furnace to obtain the silicon-vanadium alloy.

Vanadium is a strategic national resource, and the key point is the reasonable and effective utilization of vanadium resources. Among them, the vanadium-rich slag is the product obtained from the main channel (i.e. blast furnace smelting vanadium titano-magnetite) for extracting vanadium from natural vanadium-containing ore, and is a useful resource rather than solid waste. In the method, the vanadium-rich slag is used as a raw material to provide vanadium and iron, when the mass ratio of the vanadium-rich slag is less than the minimum value of the range, the vanadium content of the obtained silicon-vanadium alloy is low, and the vanadium content of the obtained silicon-vanadium nitride is not ideal, so that the method is low in return for subsequent steelmaking and uneconomical. When the mass ratio of the vanadium-rich slag is higher than the maximum value of the range, one slag becomes sticky and difficult to discharge, the recovery rate of vanadium is reduced, the carbon content of the silicon-vanadium alloy obtained by the two is high, the burden of oxidizing roasting in the subsequent step is increased, and meanwhile, the phosphorus and sulfur impurities are also high, so that great difficulty is brought to the subsequent impurity removal of steel making.

In the method of the present invention, silica is used as a raw material to supply silicon element while its addition amount also affects the basicity of slag, and when the mass ratio of silica is less than the minimum value of the above range, SiO₂The activity is low, the thermodynamic condition of reduction is poor, and the vanadium leakage amount of the slag is also increased. When the silica mass ratio is higher than the maximum value of the above range, the furnace temperature gradient is large due to the deterioration of the slag conductivity, and the furnace bottom temperature is low, so that it is difficult to satisfy SiO₂The reduction of (2) does not affect the silicon recovery rate, and Si is easily accumulatedC, and other high melting point substances.

In the method of the invention, coke is a reducing agent of the reaction in the furnace and is responsible for reducing vanadium, iron and silicon in silica in the vanadium-rich slag, and when the mass ratio of the coke is less than the minimum value of the range, the electrode is inserted too deeply, the consumption is too large, the load is not full, the current is not stable, and simultaneously, the vanadium is more leaked in the slag. When the mass ratio of the coke is larger than the maximum value of the range, the current rises, the electrode is lifted, the pressure and the temperature of furnace gas are increased, the volatilization loss of vanadium is increased, and simultaneously, the temperature of the furnace bottom is low, so that the tapping and deslagging are not smooth.

In the method, the quicklime is a slagging agent and is mainly used for adjusting the alkalinity of the slag, when the mass ratio of the quicklime to the slag is less than the minimum value of the range, the alkalinity is too low, the conductivity and the fluidity of the slag are poor, a crucible area of a molten pool is small, and the production efficiency is not high. When the mass ratio is more than the maximum value of the above range, SiO is greatly affected₂And V₂O₅Resulting in low levels of both silicon and vanadium in the alloy.

(2) Crushing and ball milling of silicon-vanadium alloy

After casting and cooling the silicon-vanadium alloy liquid ingot mold, coarsely crushing the silicon-vanadium alloy liquid ingot mold to below 20mm by a crusher, performing primary grinding by a ball mill to-100 meshes (Taylor sieve), then performing oxidizing roasting in a roasting kiln, keeping the temperature at 600-800 ℃ for 4-6 hours, and then performing secondary grinding to obtain the silicon-vanadium alloy liquid ingot mold with the particle size below 100 meshes.

In the method, the silicon-vanadium alloy is crushed and ball-milled to-100 meshes for one time, so that a larger specific surface area can be obtained, and the silicon-vanadium alloy can be fully and effectively oxidized and decarburized in a roasting kiln. The oxygen-carbon ratio is controlled within a reasonable range (the ratio is too low to affect decarburization, and the high ratio increases impurity content to affect product quality) by keeping the temperature at 600-800 ℃ for 4-6 hours. After oxidizing roasting, the silicon vanadium powder can be sintered into blocks in different degrees, so that secondary ball milling treatment is required.

(3) Press forming

And (3) adding a binder into the powder obtained in the step (2), uniformly mixing, and then performing compression molding and drying treatment under the pressure of 12-18 MPa, wherein the drying temperature is 150-250 ℃, and the drying time is 2 hours, for example.

Preferably, the binder is any one or more of water glass, polyvinyl alcohol and cellulose. More preferably, the binder is present in an amount of 3% to 6% by weight of the total mix.

In the method of the invention, a binder such as water glass, polyvinyl alcohol, cellulose and the like is added during briquetting, and the addition amount of the binder accounting for 3-6% of the total mixed material is beneficial to improving the strength and the anti-bursting temperature of the briquettes, and simultaneously, excessive impurities are not introduced. 12-18 MPa is the forming pressure suitable for subsequent transportation, drying, vacuum decarburization and nitriding treatment within a reasonable cost interval. And (3) drying before decarburization and nitridation in order to remove moisture as much as possible so as to prevent huge potential safety hazards caused by a large amount of combustible gas generated by moisture decomposition in the high-temperature link of the step (4).

(4) Vacuum decarburization and nitriding treatment

And (4) feeding the material dried in the step (3) into a vacuum resistance furnace, carrying out vacuum decarburization at 1250-1450 ℃ under the pressure of 1-10 Pa, carrying out nitriding treatment at 1000-1150 ℃ under the pressure of 80 kPa-0.1 MPa, cooling to the temperature of less than or equal to 250 ℃, and discharging to obtain the silicon nitride vanadium.

In the method, the pressure of 1-10 Pa effectively ensures the forward proceeding of the decarburization reaction, the temperature of 1250-1450 ℃ ensures that the decarburization has a good reaction speed, and meanwhile, the reaction interruption caused by the phenomenon that the material is melted to retard the escape of the reaction product CO due to overhigh temperature is avoided. The temperature of 1000-1150 ℃ and the pressure of 80 kPa-0.1 MPa are favorable for the full interaction of the silicon-vanadium alloy and nitrogen, and simultaneously, the nitrided product maintains certain stability without decomposition. When the temperature is reduced to 250 ℃ or below, the product can be effectively prevented from being oxidized too fast at high temperature, and meanwhile, the product has a certain protection effect on a furnace lining.

By adopting the method for producing silicon vanadium nitride by smelting vanadium-rich slag, the silicon vanadium nitride with the following composition can be obtained: fe 44.15-55.38 wt%, C0.14-0.45 wt%, Si 6.67-33.01 wt%, V5.85-23.04 wt%, and N7.60-14.54 wt%.

Prepared by the method of the inventionCompared with the existing silicon vanadium nitride, the silicon vanadium nitride has lower vanadium content and higher iron content, mainly because of different processes. The existing silicon vanadium nitride is usually prepared into vanadium sheets (V) from vanadium-rich slag through a series of procedures of wet method₂O₅Content (wt.)>80 percent), then reducing the vanadium sheet by ferrosilicon and aluminum particles by a fire method to obtain silicon-vanadium alloy, and nitriding the silicon-vanadium alloy. The invention directly uses vanadium-rich slag (V)₂O₅In the range of about 14% to 20%) is subjected to carbothermic reduction to obtain a silicon-vanadium alloy, which is subsequently subjected to a subsequent nitriding operation using parameters adapted thereto. The process adopted by the invention is different from the prior process, so that the content of the obtained silicon-vanadium alloy is different, but the subsequent steelmaking operation is not obviously influenced. Moreover, the process adopted by the invention abandons the traditional procedure of obtaining vanadium sheets by wet processing of vanadium-rich slag and the problems of cost investment, environmental protection and the like caused by the traditional procedure, and has obvious advancement and process crossing significance.

It should be noted that various materials involved in the method for producing silicon vanadium nitride by smelting vanadium-rich slag according to the present invention can be purchased from the market.