A feeding method for controlling the bottom temperature of a titanium slag furnace

Abstract

The present invention discloses a feeding method for controlling the bottom temperature of a titanium slag furnace, comprising the following steps: detecting the iron mouth temperature T when the liquid level is lowest after the previous slag discharge; when the iron mouth temperature T is less than a first preset temperature T1, adding a first preset amount of material M1 to the titanium slag furnace at one time, and then continuously and evenly feeding the remaining amount of material in this furnace according to the production time of this furnace; when the iron mouth temperature is equal to the first preset temperature T1, adding a second preset amount of material M2 to the titanium slag furnace at one time; when the iron mouth temperature is greater than the first preset temperature T1 and less than or equal to the second preset temperature T2, increasing the amount of material added at one time based on the increase in the iron mouth temperature compared to the first preset temperature T1, starting from the second preset amount of material M2; when the iron mouth temperature is greater than the second preset temperature T2, stopping the furnace. The present application adopts a method of combining centralized feeding first and continuous feeding later, which can effectively block the impact of heat on the furnace bottom, so that the titanium slag furnace can operate stably for a long time.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium dioxide preparation, and particularly relates to a feeding method for controlling the temperature of a titanium slag furnace bottom. Background Art

[0002] During the existing titanium slag smelting process, the furnace maintains a high temperature for extended periods, significantly impacting the furnace bottom and walls. Although the walls are constructed with refractory magnesia bricks, prolonged high-power operation can still activate and melt the dead iron layer at the bottom, thinning the walls and posing a significant risk. Power outages and furnace cooling are necessary to mitigate this risk. Cooling can take anywhere from five days to half a month, which is insufficient for continuous production and severely impacts both production and output.

[0003] Since 2014, the applicant has been using ilmenite to produce titanium slag in a titanium slag furnace. The traditional charging method has been used, namely, continuous and uniform charging, evenly distributing the total charge per heat per hour. This charging method has significant drawbacks: the slag level is relatively low after the electric furnace tapping operation, and the heat has a significant impact on the furnace bottom, which can easily melt the dead iron layer at the furnace bottom, increase the furnace wall temperature (especially the tap hole temperature rises rapidly), and even create the risk of furnace penetration. Summary of the Invention

[0004] The purpose of the present invention is to provide a feeding method for controlling the bottom temperature of a titanium slag furnace in order to solve the deficiencies of the prior art.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A feeding method for controlling the temperature of a titanium slag furnace bottom comprises the following steps:

[0007] Detect the iron mouth temperature T when the liquid level is lowest after the last slag tapping;

[0008] When the iron mouth temperature T is less than the first preset temperature T1, a first preset amount of material M1 is added to the titanium slag furnace at one time, and then the remaining amount of material in this heat is continuously and evenly fed according to the production time of this heat;

[0009] When the iron mouth temperature T=the first preset temperature T1, a second preset amount of material M2 is added to the titanium slag furnace at one time, and then the remaining amount of material in this heat is continuously and evenly fed according to the production time of this heat;

[0010] When the taphole temperature T is greater than the first preset temperature T1 and less than or equal to the second preset temperature T2, the amount of material added in one go is increased based on the increase in taphole temperature T compared to the first preset temperature T1, with the second preset material amount M2 as the starting point, and the remaining material of this heat is continuously and evenly fed according to the production time of this heat;

[0011] When the iron mouth temperature T is greater than the second preset temperature T2, the furnace is stopped and the feeding is stopped.

[0012] Preferably, the first preset temperature T1 is 650-700°C, and the first preset material quantity M1 is 3-6% of the total material quantity of the furnace;

[0013] The second preset material quantity M2 is 7-10% of the total material quantity of the current heat. When the taphole temperature T exceeds the first preset temperature T1 by 8-12°C, the amount of material added is increased by 0.8-1.2% of the total material quantity of the current heat compared to the second preset material quantity M2.

[0014] The second preset temperature T2 is 820-850°C.

[0015] Preferably, the upper limit of the amount of material added to the titanium slag furnace at one time does not exceed 20% of the total amount of material in this furnace.

[0016] Preferably, the first preset temperature T1 is 700°C, and the second preset temperature T2 is 830°C;

[0017] The corresponding relationship between the taphole temperature T and the one-time concentrated feeding amount obtained by detection is shown in Table 1:

[0018] Table 1

[0019]

[0020] Preferably, the one-time concentrated feeding time is limited to ≤15min.

[0021] Preferably, the smelting temperature of the titanium slag furnace is 1600-1700°C.

[0022] Preferably, the raw material added to the titanium slag furnace is powdered ilmenite, and the particle size of the powdered ilmenite is: +40 mesh ≤ 0, -160 mesh ≤ 20%.

[0023] The present application adopts a method of combining concentrated feeding first and continuous feeding later, which can effectively block the impact of heat on the furnace bottom and enable the titanium slag furnace to operate stably for a long time. DETAILED DESCRIPTION

[0024] The present application provides a charging method for controlling the bottom temperature of a titanium slag furnace, comprising the following steps:

[0025] Detect the iron mouth temperature T when the liquid level is lowest after the last slag tapping;

[0026] When the iron mouth temperature T is less than the first preset temperature T1, the first preset material amount M1 is added to the titanium slag furnace at one time, and then the remaining material of this heat is continuously and evenly fed according to the production time of this heat;

[0027] When the iron mouth temperature T=the first preset temperature T1, the second preset material amount M2 is added to the titanium slag furnace at one time, and then the remaining material of this heat is continuously and evenly fed according to the production time of this heat;

[0028] When the taphole temperature T is greater than the first preset temperature T1 and less than or equal to the second preset temperature T2, the amount of material added in one go is increased based on the increase in taphole temperature T compared to the first preset temperature T1, starting from the second preset material amount M2, and the remaining material of this heat is continuously and evenly fed according to the production time of this heat;

[0029] When the taphole temperature T> the second preset temperature T2, the furnace is stopped and the feeding is stopped.

[0030] The applicant has found in actual production that after slag tapping, the combination of centralized feeding and continuous feeding can effectively reduce the impact of high temperature on the furnace bottom. Specifically, first, a certain amount of ilmenite is added in a one-time centralized manner after slag tapping. The added ilmenite can effectively absorb and block the impact of heat on the furnace bottom, and then the remaining amount of material in this furnace is continuously and evenly distributed and added to the furnace. At the same time, the amount of material added in a one-time centralized manner is optimized according to the tapping hole temperature. When the tapping hole temperature is relatively low, adding a small amount of ilmenite can effectively absorb and block the impact of heat on the furnace bottom. When the tapping hole temperature is high, as the tapping hole temperature rises, the amount of material added in a one-time centralized manner is correspondingly increased to absorb excess heat. However, when the temperature continues to increase and exceeds the set limit, on the one hand, accidents are prone to occur in production at high temperatures. On the other hand, adding too much ilmenite in a one-time manner will produce heaps, affecting normal smelting. Moreover, it has been verified that the one-time centralized feeding amount is mainly related to the iron mouth temperature, and the inner diameter of the titanium slag furnace and the liquid level after slag tapping have no significant effect on the feeding amount. When the inner diameter of the titanium slag furnace is larger or the liquid level after slag tapping is lower, the one-time centralized feeding amount can be appropriately increased.

[0031] Therefore, the present application adopts a method of combining concentrated feeding first and continuous feeding later, which can effectively block the impact of heat on the furnace bottom and enable the titanium slag furnace to operate stably for a long time.

[0032] The above parameters such as the first preset temperature T1 and the first preset material quantity M1 can be adjusted accordingly according to actual production conditions.

[0033] The present application provides a preferred embodiment, wherein the first preset temperature T1 is 650-700°C, and the first preset material quantity M1 is 3-6% of the total material quantity of the current batch;

[0034] The second preset material quantity M2 is 7-10% of the total material quantity of this heat. When the taphole temperature T exceeds the first preset temperature T1 by 8-12°C, the added material quantity is increased by 0.8-1.2% of the total material quantity of this heat compared with the second preset material quantity M2.

[0035] The second preset temperature T2 is 820-850°C. Within this temperature range, a corresponding one-time concentrated charge can effectively absorb heat and function effectively. If the temperature exceeds 820-850°C, and concentrated charge still fails to curb the temperature rise, the furnace must be shut down to prevent serious accidents such as furnace breakdown. If the one-time concentrated charge is less than 3%, the taphole temperature of the titanium slag furnace will gradually rise and cannot be curbed.

[0036] Further preferably, the present application provides a typical embodiment, wherein the first preset temperature T1 is 700° C., and the second preset temperature T2 is 830° C.;

[0037] The corresponding relationship between the taphole temperature T and the one-time concentrated feeding amount obtained from the test is shown in Table 1:

[0038] Table 1

[0039]

[0040] Preferably, the one-time concentrated feeding time is limited to ≤15 minutes, more preferably 3 to 5 minutes.

[0041] Preferably, the upper limit of the amount of material added to the titanium slag furnace at one time does not exceed 20% of the material of this furnace. According to experiments, when the amount of ilmenite added at one time exceeds 20%, material heaps will be generated, affecting normal smelting.

[0042] Preferably, the smelting temperature of the titanium slag furnace is 1600-1700°C.

[0043] Preferably, the raw material added to the titanium slag furnace is powdered ilmenite, and the particle size of the powdered ilmenite is: +40 mesh ≤ 0, -160 mesh ≤ 20%. Compared with the block material, the powdered ilmenite can be better melted, reduced and absorb heat.

[0044] Example 1

[0045] Since 2014, the applicant has been using a 33MVA fully enclosed electric furnace (with a furnace inner diameter of 9.8m, a liquid level of approximately 3.0m after slag discharge, and a smelting temperature of approximately 1650°C) to smelt ilmenite. The traditional continuous and uniform feeding method has been used for charging. This feeding method periodically causes the furnace bottom to become active and the furnace wall temperature to rise. When the taphole temperature exceeds 830°C, the furnace is shut down, with each shutdown lasting 6 to 10 days. This affects production by approximately 2,500 tons per month and significantly increases production costs, becoming a bottleneck restricting titanium slag production. When the taphole temperature exceeds 600°C, although the furnace is not shut down, there is a risk of furnace penetration, and the higher the temperature, the greater the risk.

[0046] Since the beginning of 2022, the feeding method provided in this embodiment has been used for feeding, as follows:

[0047] After the slag is discharged from the previous heat, the taphole temperature T is detected. The reference table shown in Table 1 is used to first perform a one-time feeding (powdered ilmenite, particle size +40 mesh ≤ 0, -160 mesh ≤ 20%), and then the remaining material of this heat is continuously and evenly fed according to the production time of this heat. The specific feeding process is as follows:

[0048] First heat (total charge of 150 tons, production time of 10 hours): after slagging from the previous heat, the taphole temperature was detected to be 720°C. 9% of the total charge of ilmenite was added at once within 15 minutes, and the remaining 91% of the charge was continuously distributed over the remaining 9.75 hours.

[0049] The second heat (the total charge of this heat is 150 tons, the production time is 10 hours): after the slag is discharged from the previous heat, the iron mouth temperature is detected to be 705℃. 7.5% of the total charge of this heat of ilmenite is added at one time within 15 minutes, and the remaining 92.5% of the charge is continuously distributed for the remaining 9.75 hours;

[0050] The third heat (the total charge of this heat is 150 tons, the production time is 10 hours): after the slag is discharged from the previous heat, the iron mouth temperature is detected to be 680℃. 6% of the total charge of this heat of ilmenite is added at one time within 15 minutes, and the remaining 94% of the charge is continuously distributed for the remaining 9.75 hours;

[0051] Heat 4 (total charge of 150 tons, production time of 10 hours): After slagging from the previous heat, the taphole temperature was detected to be 650°C. 6% of the total charge of ilmenite was added at once within 15 minutes, and the remaining 94% of the charge was continuously distributed over the remaining 9.75 hours.

[0052] The fifth heat (the total material quantity of this heat is 150 tons, and the production time is 10 hours): after the slag is discharged from the previous heat, the iron mouth temperature is detected to be 630℃. Within 15 minutes, 5% of the total material quantity of this heat is added at one time. The remaining 95% of the material quantity is continuously distributed for the remaining 9.75 hours.

[0053] …

[0054] Heat 8 (total charge of 150 tons, production time of 10 hours): After slagging from the previous heat, the iron mouth temperature was detected to be 570°C. 3% of the total charge of this heat was added at once within 15 minutes. The remaining 97% of the charge was continuously distributed over the remaining 9.75 hours.

[0055] The above method was continued to be used for charging, and the furnace was operated continuously for half a year without any shutdown due to active furnace bottom and high iron mouth temperature. Currently, the iron mouth temperature has been stably maintained at around 500℃.

[0056] Example 2

[0057] The feeding method provided in this embodiment comprises the following steps:

[0058] After the last heat (the specifications of the titanium slag furnace are the same as those in Example 1) was discharged, the iron mouth temperature was detected to be 745°C. Within 15 minutes, 11.5% of the total material of this heat was added to ilmenite (the production time of this heat was 8h, and the total material was 120 tons). The remaining 88.5% of the material was continuously distributed to the remaining 7.75h. After the heat was discharged, the iron mouth temperature was detected to drop by 20°C. The material was continuously added according to the control table shown in Table 1. After 12 heats, the iron mouth temperature was stably maintained at about 500°C.

[0059] Example 3

[0060] The feeding method provided in this embodiment comprises the following steps:

[0061] In the previous heat (the titanium slag furnace is a 33MVA fully enclosed electric furnace with an inner diameter of 11.1m. The liquid level in the furnace is generally about 3.0m after slag tapping, and the smelting temperature is about 1650℃), the iron mouth temperature was detected to be 750℃, and 13% of the total material of this heat was added at one time within 15 minutes (the production time of this heat is 12h, and the total material is 180 tons). The remaining 87% of the material is continuously distributed to the remaining 11.75h. After the heat was tapped, the iron mouth temperature was detected to drop by 18℃, and the material was continuously added according to the control table shown in Table 2. After 15 heats, the iron mouth temperature was stably maintained at about 500℃.

[0062] Table 2

[0063]

[0064] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such changes and modifications as fall within the scope of the claims and their equivalents.

Claims

1. A feeding method for controlling the bottom temperature of a titanium slag furnace, characterized in that: The following steps are involved: Detect the iron mouth temperature T when the liquid level is lowest after the last slag tapping; When the iron mouth temperature T is less than the first preset temperature T1, a first preset amount of material M1 is added to the titanium slag furnace at one time, and then the remaining amount of material in this heat is continuously and evenly fed according to the production time of this heat; When the iron mouth temperature T=the first preset temperature T1, a second preset amount of material M2 is added to the titanium slag furnace at one time, and then the remaining amount of material in this heat is continuously and evenly fed according to the production time of this heat; When the taphole temperature T is greater than the first preset temperature T1 and less than or equal to the second preset temperature T2, the amount of material added in one go is increased based on the increase in taphole temperature T compared to the first preset temperature T1, with the second preset material amount M2 as the starting point, and the remaining material of this heat is continuously and evenly fed according to the production time of this heat; When the iron mouth temperature T> the second preset temperature T2, the furnace is stopped and the feeding is stopped; The first preset temperature T1 is 650-700°C, and the first preset material quantity M1 is 3-6% of the total material quantity of the furnace; The second preset material quantity M2 is 7-10% of the total material quantity of the current heat. When the taphole temperature T exceeds the first preset temperature T1 by 8-12°C, the amount of material added is increased by 0.8-1.2% of the total material quantity of the current heat compared to the second preset material quantity M2. The second preset temperature T2 is 820-850°C.

2. The charging method for controlling the bottom temperature of a titanium slag furnace according to claim 1, characterized in that: The upper limit of the amount of materials added to the titanium slag furnace at one time shall not exceed 20% of the total amount of materials in this furnace.

3. The charging method for controlling the bottom temperature of a titanium slag furnace according to claim 1, characterized in that: The first preset temperature T1 is 700° C., and the second preset temperature T2 is 830° C.; The corresponding relationship between the taphole temperature T and the one-time concentrated feeding amount obtained by detection is shown in Table 1: Table 1 4. The charging method for controlling the bottom temperature of a titanium slag furnace according to claim 1, wherein: The one-time concentrated feeding time is limited to ≤15min.

5. The charging method for controlling the bottom temperature of a titanium slag furnace according to claim 1, characterized in that: The smelting temperature of the titanium slag furnace is 1600-1700°C.

6. The charging method for controlling the bottom temperature of a titanium slag furnace according to claim 1, characterized in that: The raw material added to the titanium slag furnace is powdered ilmenite, and the particle size of the powdered ilmenite is: +40 mesh ≤ 0, -160 mesh ≤ 20%.

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