CN112095043A

CN112095043A - Titanium removing method for high-titanium phosphorus iron alloy

Info

Publication number: CN112095043A
Application number: CN202010977872.9A
Authority: CN
Inventors: 朱翔鹰; 苏旭平; 王建华; 涂浩; 陈军修; 黄晓中
Original assignee: Jiangsu Jiangnan Ferroalloy Co ltd; Changzhou University
Current assignee: Jiangsu Jiangnan Ferroalloy Co ltd; Changzhou University
Priority date: 2020-09-17
Filing date: 2020-09-17
Publication date: 2020-12-18

Abstract

The invention discloses a titanium removing method for a high-titanium phosphorus iron alloy, which comprises the following steps: loading 10-400 meshes of high-titanium phosphorus ferroalloy powder into a tray, controlling the thickness of cloth to be 1-10 cm, then placing the tray into a heating furnace, continuously introducing carbon dioxide gas into the heating furnace, and heating for 1-24 hours at 750-1000 ℃ (300-400 ℃ lower than the melting point of high-titanium phosphorus ferroalloy); the heating furnace is provided with a tail gas discharge port, the discharge port is always opened in the reaction process and discharges tail gas, and the volume concentration of carbon dioxide in the tail gas is controlled to be 10-90%; then putting the ferrophosphorus alloy into a melting furnace for melting to obtain alloy liquid and slag floating on the alloy liquid surface, pouring the alloy liquid and the slag into a steel die, naturally layering the alloy liquid and the slag, and cooling and forming; and finally, breaking the cooled and formed alloy blocks and slag blocks, and manually sorting to obtain the low-titanium-phosphorus-iron alloy ingot, wherein Ti is less than 0.03 wt.%. The titanium removing process has the advantages of low cost, good effect, environmental protection and industrial popularization value.

Description

Titanium removing method for high-titanium phosphorus iron alloy

Technical Field

The invention belongs to the technical field of pure ferroalloy smelting production, and particularly relates to a titanium removing method for a high-titanium phosphorus ferroalloy.

Background

Every 1 ton of yellow phosphorus is produced in the yellow phosphorus industry, 0.1-0.2 ton of byproduct ferrophosphorus alloy is produced, and about 14 million tons of industrial ferrophosphorus alloy can be produced all the year according to the calculation of about 95 million tons of yellow phosphorus yield in China in 2018. The waste contains various impurity elements, the content of the impurities fluctuates between 0.5 and 15 percent, and the industrial utilization value is extremely low. There are three trends in current commercial ferrophosphorus alloys: firstly, enterprises are buried as garbage, so that the environment is polluted and resources are wasted; secondly, the device is overstocked in a factory, occupies a field and affects enterprise operation; and thirdly, the components are relatively good and can be sold as common ferrophosphorus alloy, and the price is extremely low.

The research reports of Ouyang Page et al indicate that the addition of phosphorus element to non-oriented silicon steel can reduce iron loss, improve punching performance and increase magnetic induction strength. The ferrophosphorus alloy can be used as phosphorus element to be added during the smelting of silicon steel. Because titanium element can be combined with C, N, O to generate inclusions and influence the performance of silicon steel, the requirement of silicon steel plants on the content of titanium element in ferrophosphorus alloy is very high, and is generally less than 0.05 wt.%. If the phosphorus-iron alloy byproduct in the yellow phosphorus industry can be used as a raw material to perform smelting and titanium removal to obtain the low-titanium phosphorus-iron alloy for silicon steel smelting, the additional value of the phosphorus-iron alloy byproduct in the yellow phosphorus industry can be obviously improved.

The patent CN110055452A by Octopus et al of Anhui university of industry discloses a process for treating yellow phosphorus and a byproduct ferrophosphorus alloy, and the ferrophosphorus alloy produced by the process can be used for producing high-quality silicon steel. The specific operation of the process is as follows: nitrogen or ammonia is blown into the high-titanium ferrophosphorus melt, the generated titanium nitride is absorbed by the absorption slag, and the ferrophosphorus finished product components are obtained after slag-metal separation: p: 23-25%, Si: 1.7-2.8%, C: 0.8-0.9%, S: 0.05-0.08%, Mn: 0.8-1.7%, Cr: 0.6-0.8%, Ti less than 0.05%, and the balance of Fe. The process utilizes the nitridation reaction of Ti element to remove the Ti content, but can not remove other impurities. In the method, the gas is adopted to blow the high-temperature ferrophosphorus melt, so that the operation time is long, and P steam is seriously volatilized, so that the phosphorus content in the final ferrophosphorus alloy is reduced. Particularly, when ammonia gas is used as blowing gas, the smelting environment is relatively severe, which is not good for the health of workers and increases the environmental management cost.

Therefore, how to remove titanium in ferrophosphorus alloy in an efficient and environment-friendly way is an urgent problem to be solved.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the high titanium phosphorus iron alloy has high titanium content, and cannot be applied to smelting high-quality silicon steel.

The invention solves the technical problems through the following technical scheme, and the titanium removing method for the high-titanium phosphorus iron alloy comprises the following steps:

(1) milling: preparing high-titanium phosphorus ferroalloy powder with the granularity of 10-400 meshes from high-titanium phosphorus ferroalloy raw material blocks by adopting a crushing and grinding mode;

(2) and (3) oxidation: loading the high-titanium phosphorus ferroalloy powder obtained in the step (1) into a tray, controlling the cloth thickness of the high-titanium phosphorus ferroalloy powder to be 1-10 cm, then placing the tray into a heating furnace, continuously introducing carbon dioxide gas into the heating furnace, controlling the temperature of powder to be 750-1000 ℃ and 300-400 ℃ lower than the melting point of the high-titanium phosphorus ferroalloy, and controlling the heating time to be 1-24 hours; the heating furnace is provided with a tail gas discharge port, the discharge port is always in an open state in the reaction process and discharges tail gas, the flow of the carbon dioxide gas is controlled according to the volume concentration of the carbon dioxide in the tail gas, and the volume concentration of the carbon dioxide in the tail gas is controlled to be 10-90%;

(3) melting: putting the ferrophosphorus alloy obtained in the step (2) into a melting furnace for melting, controlling the melting temperature to be 1400-1600 ℃, and obtaining molten alloy liquid and slag floating on the alloy liquid surface;

(4) casting: pouring the alloy liquid and the slag obtained in the step (3) into a steel casting mould, naturally layering the alloy liquid and the slag due to specific gravity difference, and cooling and forming;

(5) separation: and (4) breaking the alloy blocks and the slag blocks formed by cooling in the step (4), and manually sorting to obtain low-titanium phosphorus iron alloy ingots.

Further, the mass content of titanium in the high-titanium phosphorus iron alloy is as follows: 0.10% < Ti < 5.0% ".

Further, in the step (1), a jaw crusher or a hammer crusher is adopted as a crushing mode, and a ball mill or a Raymond mill is adopted as a grinding mode.

Further, in the step (1), the particle size range of the high titanium phosphorus iron alloy powder is 10-400 meshes, more preferably 200-300 meshes, and the most preferred value is 250 meshes.

Further, in the step (2), the heating furnace into which the carbon dioxide gas is introduced is an electrically heated atmospheric pressure furnace, the atmospheric pressure furnace has an air inlet and an exhaust port, the carbon dioxide gas flows through the air inlet, the exhaust port discharges the exhaust gas after the reaction, and the exhaust gas generally contains carbon dioxide and carbon monoxide gas.

Further, in the step (2), the cloth thickness range of the high titanium phosphorus iron alloy powder is 1-10 cm, more preferably 3-5 cm, and the optimal value is 4 cm.

Further, in the step (2), the volume concentration of carbon dioxide in the tail gas is controlled to be 50-80%, and the optimal value is 65%.

Further, in the step (2), the temperature of the powder material ranges from 850 ℃ to 900 ℃.

Further, in the step (2), the heating time is the time for the high titanium phosphorus iron alloy powder to stay in the heating furnace, and the heating time is 6-12 hours.

In the step (5), the mass content of Ti in the low-titanium ferrophosphorus alloy ingot is less than 0.03%, and the mass content of P, Si, Mn, Cr, C and S in the low-titanium ferrophosphorus alloy ingot is respectively reduced by about 1-2% compared with the mass content of P, Si, Mn, Cr, C and S in the original high-titanium ferrophosphorus alloy raw material block.

A low-titanium phosphorus iron alloy prepared by the titanium removing method of the high-titanium phosphorus iron alloy.

A low-Ti-P-Fe alloy can be used for smelting silicon steel.

The main impurity elements contained in the phosphorus-iron alloy as the byproduct of the yellow phosphorus industry are Ti, Si, Mn, Cr and the like, and the impurity elements are mainly dissolved in the phosphorus-iron alloy in a simple substance form during melting. Three main phases, FeP phase and Fe, exist in the solid phase high titanium phosphorus iron alloy₂P and Fe₃The P phase, and Ti element is mainly dissolved in these three phases. According to the Ellingham oxygen potential diagram, the affinity of Ti, Si, Mn and Cr to oxygen is higher than that of Fe and P, wherein the affinity of Ti element to oxygen is strongest. Theoretically, an oxidant with higher oxygen potential can be selected to oxidize the active metal elements, and the oxidation of Fe and P by the oxygen potential is reduced as much as possible or does not occur. Researches show that carbon dioxide meets the requirements, and in order to solve the problems of phosphorus loss and energy consumption increase caused by long-time gas blowing of the high-titanium-phosphorus-iron alloy melt, the carbon dioxide blowing impurity removal reaction is carried out at 300-400 ℃ below the melting point of the high-titanium-phosphorus-iron alloy. Therefore, the impurity removing reaction of the high titanium phosphorus ferroalloy titanium removing process is a gas-solid reaction. In order to improve the gas-solid reaction speed, three factors of the reaction temperature, the particle size of the ferrophosphorus alloy and the carbon dioxide concentration need to be controlled. The reaction speed rapidly increases along with the increase of the reaction temperature, but the impurity removing reaction is an oxidation exothermic reaction, and the high impurity removing reaction temperature easily causes the ferrophosphorus alloy to sinter and even melt, is not beneficial to the diffusion of atoms in the medium, and reduces the reaction speed, so the impurity removing reaction temperature is controlled below 1000 ℃ (namely the powder temperature in the step (2) needs to be controlled below 1000 ℃). When the reaction temperature is less than 750 ℃, the reaction speed is very slow and there is no production economy, so the reaction temperature should be more than 750 ℃. The smaller the granularity of the high-titanium phosphorus iron alloy is, the larger the surface area is, the shorter the diffusion path of atoms in the particles is, and the faster the gas-solid reaction speed is, but the too high speed easily causes local high-temperature sintering, and affects the overall reaction speed, so the granularity needs to be controlled within a proper range, and experiments prove that the granularity range of 10-400 meshes is usable, and particularly the granularity range of 200-300 meshes is the optimal granularity range. Atmosphere furnaceThe higher the internal carbon dioxide concentration, the higher the oxygen potential, and the faster the reaction to oxidize the impurity elements. Carbon dioxide oxidizes impurity elements to generate carbon monoxide, and the concentration of the carbon dioxide is correspondingly reduced. In order to maintain a certain carbon dioxide concentration, fresh carbon dioxide gas must be continuously introduced while the reaction off-gas is discharged. The volume concentration of carbon dioxide in tail gas is adjusted by controlling the flow of the introduced carbon dioxide, thereby ensuring the oxygen potential in the furnace. If the concentration of carbon dioxide in the tail gas is too high, the consumption of carbon dioxide is increased, and the more heat is taken away by the gas. If the concentration of carbon dioxide in the tail gas is too low, the oxygen potential in the furnace is too low, the impurity removal oxidation reaction is slow, and the production efficiency is influenced. Through experiments, the volume concentration of carbon dioxide in tail gas is feasible to be controlled within 10-90%, and the optimal range is 50-80%.

After the high titanium phosphorus iron alloy is oxidized by carbon dioxide, most of titanium elements are oxidized, and other impurity elements, namely Si, Mn and Cr, are partially oxidized to generate corresponding oxides. And putting the oxidized ferrophosphorus alloy into a melting furnace for melting, controlling the melting temperature to be 1400-1600 ℃, and obtaining molten alloy liquid and slag floating on the alloy liquid surface. The slag contains titanium oxide, silicon oxide, manganese oxide, chromium oxide, iron oxide and phosphorus oxide. And pouring the molten alloy liquid and the slag into a steel casting mold, naturally layering the alloy liquid and the slag due to specific gravity difference, and cooling and molding. And breaking the cooled and formed alloy blocks and slag blocks, and manually sorting to obtain the low-titanium phosphorus iron alloy ingot.

The invention has the following advantages:

1. the method adopts cheap carbon dioxide gas as an oxidant to selectively oxidize titanium elements and other active impurity elements in the high-titanium ferrophosphorus alloy, and has obvious advantages in the aspects of economy, environmental protection and safety.

2. The high titanium phosphorus iron alloy after oxidation treatment only needs to be melted and cast quickly, so that the liquid operating time of the phosphorus iron alloy is shortened, the volatilization of phosphorus at high temperature is avoided, the phosphorus yield is improved, the environmental pollution is reduced, and the operating environment of workers is improved.

3. Besides titanium element, other impurity elements (Si, Mn, Cr) and iron are also partially oxidized, and the oxides form a low-temperature slag system at high temperature without a slagging agent, so that the production cost is reduced, and the slag output is reduced.

Drawings

FIG. 1 is an SEM image of a high titanium ferrophosphorus alloy as a starting material in example 1;

FIG. 2 is a graph of EDS spectrum analysis of high phosphorus phase (sampled as "+" in FIG. 1) of high titanium ferrophosphorus alloy as a starting material in example 1;

FIG. 3 is an SEM image of a high titanium phosphorous iron alloy of example 1 as a starting material;

FIG. 4 is a graph of EDS spectrum analysis of low phosphorus phase (at the "+" sampling point in FIG. 3) of high titanium ferrophosphorus alloy as a starting material in example 1;

FIG. 5 is an SEM image of a low titanium phosphorous iron alloy of example 1 as a finished product;

FIG. 6 is a graph of EDS spectrum analysis of high phosphorus phase (FIG. 5 frame sample) of the low titanium phosphorous iron alloy of example 1 as a finished product;

FIG. 7 is an SEM image of a low titanium phosphorous iron alloy of example 1 as a finished product;

FIG. 8 is a graph of EDS spectrum analysis of the low phosphorus phase (sampled in the shape of the box of FIG. 7) of the low titanium phosphorous iron alloy of example 1 as a finished product.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.

Example 1

Sampling and testing the high-titanium phosphorus ferroalloy to be processed, wherein the components are as follows: 26.5% of P, 2.2% of Ti, Si: 2.2%, Mn: 1.1%, Cr: 0.8%, C: 0.1%, S: 0.05% and the balance Fe. Putting the high-titanium-phosphorus-iron alloy raw material blocks into a hammering type crusher, crushing until the granularity is less than 1cm, and then putting the crushed high-titanium-phosphorus-iron alloy raw material blocks into a ball mill for ball milling until the granularity is 200-300 meshes. 10kg of ground high-titanium phosphorus iron powder is loaded into a tray, the material distribution thickness is 3cm, the tray is placed into an atmosphere furnace (a tail gas discharge port of the atmosphere furnace is in an open state and is used for discharging tail gas in the reaction process in real time, the same is applied below), carbon dioxide gas is continuously introduced, the temperature of the powder is raised to 900 ℃, the temperature is kept, and the flow of the carbon dioxide gas is adjusted to ensure that the concentration of the carbon dioxide in the tail gas is between 70 and 80 percent. And (4) after the temperature is preserved and the gas is ventilated for 8 hours, taking out the oxidized material, putting the oxidized material into an intermediate frequency furnace, quickly melting the oxidized material, controlling the melting temperature to be 1400 ℃, and casting after separating slag and gold. After the ingot casting is cooled, ingot and slag are knocked to be broken, alloy ingots are manually sorted out, and the components of finished products are sampled and tested: 24.3% of P, 0.005% of Ti, Si: 1.8%, Mn: 0.8%, Cr: 0.4%, C: 0.1%, S: 0.05% and the balance Fe.

Example 2

The conditions are the same as example 1 except that the powder is heated to 750 ℃ for heat preservation, and the final product sampling and testing components are as follows: 24.7% of P, 0.008% of Ti, Si: 1.9%, Mn: 0.9%, Cr: 0.39%, C: 0.09%, S: 0.048 percent and the balance of Fe.

Example 3

The conditions are the same as example 1 except that the powder is heated to 1000 ℃ and the temperature is kept, and the final product is sampled and tested according to the following components: 23.8% of P, 0.015% of Ti, Si: 1.5%, Mn: 0.6%, Cr: 0.38%, C: 0.09%, S: 0.045% and the balance of Fe.

Example 4

Except that the granularity of the raw material ferrophosphorus powder is 300-400 meshes, the other conditions are the same as the example 1, and the final product sampling assay components are as follows: 24.5% of P, 0.013% of Ti, Si: 1.7%, Mn: 0, 8%, Cr: 0.36%, C: 0.09%, S: 0.05% and the balance Fe.

Example 5

The method is the same as the example 1 except that the granularity of the raw material ferrophosphorus powder is 100-200 meshes, and the final product comprises the following components in a sampling and testing way: 24.5% of P, 0.012% of Ti, Si: 1.8%, Mn: 0, 8%, Cr: 0.36%, C: 0.1%, S: 0.049 percent and the balance of Fe.

Example 6

The method is the same as the example 1 except that the granularity of the raw material ferrophosphorus powder is 10-100 meshes, and the final product is prepared by the following components in a sampling and testing way: 24.7% of P, 0.028% of Ti, Si: 1.9%, Mn: 0.9%, Cr: 0.37%, C: 0.1%, S: 0.05% and the balance Fe.

Example 7

The conditions were the same as in example 1 except that the incubation and aeration were carried out for 5 hours, and the final product was sampled and assayed as follows: 24.9% of P, 0.05% of Ti, Si: 2.0%, Mn: 1.0%, Cr: 0.45%, C: 0.1%, S: 0.05% and the balance Fe.

Example 8

The conditions were the same as in example 1 except that the incubation and aeration were carried out for 15 hours, and the final product was sampled and assayed as follows: 24.0% of P, 0.004% of Ti, Si: 1.7%, Mn: 0.7%, Cr: 0.38%, C: 0.09%, S: 0.045% and the balance of Fe.

Example 9

The conditions were the same as in example 1 except that the thickness of the cloth was 1cm, and the final product was sampled and tested as follows: 24.3% of P, 0.005% of Ti, Si: 1.8%, Mn: 0.8%, Cr: 0.39%, C: 0.09%, S: 0.045% and the balance of Fe.

Example 10

The conditions were the same as in example 1 except that the thickness of the cloth was 10 cm, and the final product was sampled and tested as follows: 24.6% of P, 0.1% of Ti, Si: 2.0%, Mn: 1.5%, Cr: 0.65%, C: 0.1%, S: 0.05% and the balance Fe.

Example 11

Sampling and testing the high-titanium phosphorus ferroalloy to be processed, wherein the components are as follows: 25.7% of P, 1.5% of Ti, Si: 1.4%, Mn: 2.0%, Cr: 1.1%, C: 0.15%, S: 0.06 percent and the balance of Fe. Putting the high-titanium phosphorus iron alloy raw material block to be subjected to titanium removal into a jaw crusher, crushing until the granularity is less than 3cm, and then putting into a Raymond mill to be ground until the granularity is 200-300 meshes. 10kg of ground high-titanium phosphorus iron powder is loaded into a tray, the cloth thickness is 4cm, the tray is placed into an atmosphere furnace, carbon dioxide gas is continuously introduced, the temperature of the powder is raised to 900 ℃, the temperature is kept, and the flow of the carbon dioxide gas is adjusted to enable the concentration of the carbon dioxide in tail gas to be between 50% and 60%. And (4) after the temperature is preserved and the gas is ventilated for 8 hours, taking out the oxidized material, putting the oxidized material into an intermediate frequency furnace, quickly melting the oxidized material, controlling the melting temperature to be 1450 ℃, and casting after separating slag and gold. After the ingot casting is cooled, ingot and slag are knocked to be broken, alloy ingots are manually sorted out, and finally, the components of a finished product are sampled and tested: 23.4% of P, 0.008% of Ti, Si: 0.8%, Mn: 0.8%, Cr: 0.55%, C: 0.13%, S: 0.05% and the balance Fe.

Example 12

Except that the concentration of carbon dioxide is 10-20%, the conditions are the same as those in the embodiment 11, and the final product comprises the following components in a sampling and testing way: 23.6% of P, 0.3% of Ti, Si: 1.2%, Mn: 1.6%, Cr: 0.85%, C: 0.15%, S: 0.06 percent and the balance of Fe.

Example 13

Except that the concentration of carbon dioxide is 90-95%, the conditions are the same as those in the embodiment 11, and the final product comprises the following components in a sampling and testing way: 23.2% of P, 0.006% of Ti, Si: 0.6%, Mn: 0.6%, Cr: 0.45%, C: 0.10%, S: 0.045% and the balance of Fe.

Tables 1 to 4 show the results of EDS spectroscopy in fig. 2, 4, 6 and 8, respectively.

TABLE 1

Element(s)	Si	P	Ti	Mn	Fe	Σ
							By weight%	0.09	37.4	0.16	0.92	61.44	100
Atom%	0.13	51.81	0.14	0.71	47.2	100

TABLE 2

Element(s)	Si	P	Ti	Mn	Fe	Σ
							By weight%	0.05	23.36	3.08	2.46	71.05	100
Atom%	0.08	35.28	3.01	2.1	59.53	100

TABLE 3

Element(s)	Si	P	Ti	Mn	Fe	Σ
							By weight%	0.27	38.79	0.00	0.02	60.92	100
Atom%	0.4	53.22	0.00	0.02	46.36	100

TABLE 4

Element(s)	Si	P	Ti	Mn	Fe	Σ
							By weight%	0.09	24.32	0.02	0.07	75.5	100
Atom%	0.16	36.65	0.02	0.06	63.11	100

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A titanium removing method for a high-titanium phosphorus iron alloy comprises the following steps:

2. The titanium removing method for the high-titanium phosphorus-iron alloy according to claim 1, wherein the mass content of titanium in the high-titanium phosphorus-iron alloy is as follows: 0.10% < Ti < 5.0% ".

3. The method for removing titanium from a high-titanium-phosphorus-iron alloy according to claim 1, wherein in the step (1), a jaw crusher or a hammer crusher is adopted as a crushing mode, and a ball mill or a Raymond mill is adopted as a grinding mode.

4. The method for removing titanium from the high titanium phosphorus iron alloy according to claim 1, wherein in the step (1), the particle size of the high titanium phosphorus iron alloy powder is 200-300 meshes.

5. The method of claim 1, wherein the high-Ti-P-Fe alloy powder has a particle size of 250 mesh.

6. The titanium removing method for the high titanium phosphorus iron alloy according to claim 1, wherein in the step (2), the cloth thickness of the high titanium phosphorus iron alloy powder is 3-5 cm.

7. The method for removing titanium from the high titanium phosphorus iron alloy according to claim 1, wherein in the step (2), the cloth thickness of the high titanium phosphorus iron alloy powder is 4 cm.

8. The method for removing titanium from a high-titanium ferrophosphorus alloy as claimed in claim 1, wherein in the step (2), the volume concentration of carbon dioxide in the tail gas is controlled to be 50-80%.

9. The method for removing titanium from a high-titanium ferrophosphorus alloy according to claim 1, wherein in the step (2), the volume concentration of carbon dioxide in the tail gas is controlled to be an optimal value of 65%.

10. The method for removing titanium from the high-titanium ferrophosphorus alloy as claimed in claim 1, wherein in the step (2), the temperature of the powder is controlled to be 850-900 ℃;

and/or in the step (2), the heating time is 6-12 hours.