A method for cleaning plate-agglomerated material in a rotary kiln

Abstract

The present invention discloses a method for cleaning agglomerated materials in a rotary kiln, comprising: (1) preparing a xanthan gum aqueous solution; (2) spraying the xanthan gum aqueous solution onto the surface of the agglomerated materials in the rotary kiln; (3) controlling the rotary kiln to idle at a low temperature for a predetermined time and then heating up; (4) supplying heat to the rotary kiln to increase the temperature of the agglomerated materials in the rotary kiln and to keep the temperature insulated, while controlling the rotary kiln rotation speed; (5) determining whether to repeat the operations of steps (2) to (4) based on the amount of agglomerated materials discharged from the kiln tail discharge end until the agglomerated materials on the inner wall of the rotary kiln and the outer wall of the return air duct are completely detached. The method utilizes the xanthan gum aqueous solution as a cleaning agent and is supplemented by a suitable cleaning process. The method can efficiently and conveniently clean the agglomerated materials on the inner wall and the return air duct of an indirect drying titanium concentrate rotary kiln, without adding too many additional components in the kiln, thereby reducing labor intensity and operation time and improving productivity.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium concentrate production and processing, and in particular relates to a method for cleaning agglomerated materials in a rotary kiln. Background Art

[0002] Titanium concentrate production is based on tailings from iron-containing composite iron ores, which are then enriched after beneficiation. Titanium concentrate enrichment methods are primarily categorized into dry and wet processes. Dry processes include electric furnace smelting, plasma smelting, selective chlorination, and other thermal reduction methods. Wet processes include partial reduction-hydrochloric acid leaching, partial reduction-sulfuric acid leaching, reduction corrosion, and full reduction-hydrochloric acid leaching. Both dry and wet methods involve high-temperature processing of titanium concentrate. However, after flotation, titanium concentrate typically contains 8-12% moisture. Directly subjecting this water-containing titanium concentrate to high-temperature processes will negatively impact the redox roasting efficiency and energy consumption. Therefore, drying and dehydrating the water-containing titanium concentrate before feeding it into the furnace is essential.

[0003] The commonly used drying method for titanium concentrate is to use rotary kiln drying. Rotary kiln drying is to dry the water-containing titanium concentrate by contacting it with high-temperature flue gas. In this drying method, the flotation titanium concentrate enters the kiln from one end of the rotary kiln, is heated and dried during the movement in the kiln, and is finally discharged from the lower discharge port at the other end of the kiln body. There are two drying methods for titanium concentrate: direct drying and indirect drying. Since the titanium concentrate has fine particle size and a wide particle size distribution range, particles below 200 mesh (0.074mm) account for more than 75%; the material has high moisture content and is easy to agglomerate; the specific gravity is high, and the true specific gravity reaches 4.30t / m 3 Due to its poor fluidity and other characteristics, direct drying of titanium concentrate results in significant losses and a poor production environment. Furthermore, due to the high initial temperature during the drying process, flotation agents are easily decomposed or volatilized, emitting a pungent odor, polluting the environment and seriously affecting people's lives. Indirect drying is more environmentally friendly and appropriate for drying titanium concentrate. However, due to the high specific gravity of titanium concentrate, it slides along the inner wall of the drying rotary kiln after entering it, resulting in fine particle size and high moisture content. Indirect drying can cause the titanium concentrate to cling to the flue gas return duct and the inner wall of the drying rotary kiln, increasing equipment load and reducing production efficiency.

[0004] Based on the above technical background, it is necessary to propose a method for cleaning the plate-agglomerated material in the rotary kiln. Summary of the Invention

[0005] To address at least one of the existing technical problems, the present invention provides a method for cleaning aggregated material within a rotary kiln. This method utilizes a xanthan gum aqueous solution as a cleaning agent, supplemented by a suitable cleaning process, to efficiently and conveniently clean aggregated material from the inner walls and return air duct of a rotary kiln for indirect drying of titanium concentrate. This method eliminates the need for numerous additional components within the kiln, reduces labor intensity and operating time, and improves productivity.

[0006] According to the present invention, a method for cleaning agglomerated material in a rotary kiln is provided, comprising:

[0007] (1) preparing a xanthan gum aqueous solution;

[0008] (2) spraying the xanthan gum aqueous solution onto the surface of the plate-bound material in the rotary kiln;

[0009] (3) Control the rotary kiln to run idle at low temperature for a predetermined time before heating up;

[0010] (4) supplying heat to the rotary kiln to increase the temperature of the aggregate in the rotary kiln and keep it warm, while controlling the speed of the rotary kiln;

[0011] (5) Determine whether to repeat steps (2) to (4) based on the amount of agglomerated material discharged from the kiln tail discharge end until the agglomerated material on the inner wall of the rotary kiln and the outer wall of the return air duct is completely removed.

[0012] According to one embodiment of the present invention, in step (1), the mass ratio of xanthan gum to water is 0.18% to 0.25%.

[0013] According to one embodiment of the present invention, in step (2), before spraying the xanthan gum aqueous solution into the rotary kiln, the temperature of the inner wall of the rotary kiln is controlled to be below 60°C.

[0014] According to one embodiment of the present invention, in step (2), before spraying the xanthan gum aqueous solution into the rotary kiln, the rotation speed of the rotary kiln is controlled to be 0.5 r / min to 0.8 r / min.

[0015] According to one embodiment of the present invention, the step (2) of spraying the xanthan gum solution into the rotary kiln includes spraying the xanthan gum solution into the surface of the plate material in the rotary kiln at a pressure of 0.4Mpa to 0.5Mpa, and the amount of the xanthan gum solution used each time is 1.8kg / m 2 ~2.1kg / m 2 .

[0016] According to one embodiment of the present invention, spraying the xanthan gum aqueous solution into the rotary kiln in step (2) includes spraying the xanthan gum aqueous solution from the kiln head at the feed end and the kiln tail at the discharge end.

[0017] According to one embodiment of the present invention, 75% to 80% of the total amount is sprayed into the kiln head at the feeding end, and 20% to 25% of the total amount is sprayed into the kiln tail at the discharging end.

[0018] According to one embodiment of the present invention, the temperature of the low-temperature idling in step (3) does not exceed 60° C., the rotation speed is controlled at 0.5 r / min to 0.8 r / min, and the rotation time is controlled at 100 min to 120 min.

[0019] According to one embodiment of the present invention, in step (4), the temperature of the slab material is raised to 130° C. to 150° C., the holding time is controlled at 60 min to 75 min, and the rotation speed of the rotary kiln is controlled at 3.5 r / min to 4.0 r / min.

[0020] According to one embodiment of the present invention, in step (2), the xanthan gum aqueous solution is sprayed into the rotary kiln using a steel pipe with multiple atomizing nozzles. The steel pipe is placed into the rotary kiln through the observation ports of the kiln head fixed seat and the kiln tail fixed seat of the rotary kiln, and it is ensured that the extension range of the steel pipe at the kiln head and the kiln tail covers the entire axial range of the rotary kiln.

[0021] Due to the adoption of the above technical scheme, the present invention has the following beneficial effects compared with the prior art: the method of the present invention utilizes xanthan gum aqueous solution as a cleaning agent, supplemented by suitable cleaning process materials, and can achieve the effect of efficiently and conveniently cleaning the compacted materials on the inner wall and return air pipe of the indirect drying titanium concentrate rotary kiln without adding too many additional components in the furnace, which saves manufacturing costs, reduces manual labor intensity and operation time, and improves productivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 Schematic diagram of the relevant structure of the method for cleaning the compacted material in the rotary kiln according to an embodiment of the present invention.

[0024] List of reference numerals:

[0025] 1 Steel pipe with atomizing nozzle; 2 Kiln head fixed seat; 3 Rotary kiln body; 4 Dust removal pipe; 5 Return air pipe; 6 Kiln tail fixed seat. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] The present invention provides a method for cleaning aggregated material in a rotary kiln. The overall concept of the method is to use a low-concentration xanthan gum aqueous solution, allowing the xanthan gum aqueous solution to fully penetrate the aggregated material in the early stage. Due to the viscosity of the xanthan gum aqueous solution, the aggregated material and the xanthan gum are combined. Later, the temperature is raised to evaporate the water in the solution, which is prone to cracking. Combined with centrifugal action, the mixture of xanthan gum and aggregated material on the inner wall of the rotary kiln and the outer wall of the return air duct is removed. The method generally comprises the following steps:

[0028] (1) preparing a xanthan gum aqueous solution;

[0029] (2) spraying the xanthan gum aqueous solution onto the surface of the plate-bound material in the rotary kiln;

[0030] (3) Control the rotary kiln to run idle at low temperature for a predetermined time before heating up;

[0031] (4) supplying heat to the rotary kiln to increase the temperature of the aggregate in the rotary kiln and keep it warm, while controlling the speed of the rotary kiln;

[0032] (5) Determine whether to repeat steps (2) to (4) based on the amount of agglomerated material discharged from the kiln tail discharge end until the agglomerated material on the inner wall of the rotary kiln and the outer wall of the return air duct is completely removed.

[0033] The following is a detailed introduction to each step of the method.

[0034] In step (1), the mass ratio of xanthan gum to water is controlled at 0.18% to 0.25%. If the mass concentration of the xanthan gum aqueous solution is too high, the sol will have poor fluidity and be difficult to penetrate into the compacted material, while if the mass concentration is too low, the number of spraying times of the xanthan gum solution will increase, which will increase the cleaning time.

[0035] In step (2), before spraying the xanthan gum solution into the rotary kiln, the temperature of the inner wall of the rotary kiln is controlled to be below 60°C. Too high a temperature will cause the water in the xanthan gum solution added subsequently to evaporate quickly, so that the xanthan gum solution does not have time to flow and diffuse and cannot penetrate and infiltrate the compacted materials, resulting in a significant reduction in the cleaning effect. Before spraying the xanthan gum solution into the rotary kiln, the rotation speed of the rotary kiln is controlled to be 0.5r / min~0.8r / min, and the rotation speed of the rotary kiln is controlled within an appropriate range to avoid the xanthan gum solution added later flowing too fast and failing to ensure sufficient wetting and penetration time. When spraying the xanthan gum solution into the rotary kiln, the xanthan gum solution is sprayed into the surface of the compacted materials in the rotary kiln at a pressure of 0.4Mpa~0.5Mpa, and the amount of xanthan gum solution used each time can be controlled to be 1.8kg / m 2 ~2.1kg / m 2The xanthan gum solution can be sprayed into the kiln head at the feed end and the kiln tail at the discharge end, with 75% to 80% of the total amount sprayed into the kiln head at the feed end and 20% to 25% of the total amount sprayed into the kiln tail at the discharge end. The xanthan gum solution can be sprayed into the kiln using a steel pipe with multiple atomizing nozzles. The steel pipe can be placed into the rotary kiln through the observation ports of the kiln head and kiln tail fixed seats of the rotary kiln, while ensuring that the extension range of the steel pipes at the kiln head and kiln tail covers the entire axial range of the rotary kiln.

[0036] In step (3), after spraying the xanthan gum solution, the steel pipe is withdrawn and the rotary kiln is controlled to idle at low temperature. The temperature of the low temperature idle operation does not exceed 60°C, the rotation speed is controlled at 0.5r / min to 0.8r / min, and the rotation time is controlled at 100min to 120min. Xanthan gum has pseudoplasticity. The xanthan gum solution has high viscosity under static or low shearing action. Under high shearing action, the viscosity drops sharply, but the molecular structure remains unchanged. When the shearing force is eliminated, the original viscosity is immediately restored. The relationship between shearing force and viscosity is completely plastic. In the present invention, after spraying the xanthan gum solution into the rotary kiln, the rotary kiln is idle at low temperature. The viscosity of the xanthan gum solution drops sharply under shearing action, making it easier for the xanthan gum solution to penetrate the compacted material. This operation allows the xanthan gum solution to fully penetrate and infiltrate the compacted material. Moreover, the rotation of the rotary kiln causes the xanthan gum solution to be evenly distributed on the circumference of the inner wall of the rotary kiln, so that the compacted material within the entire range can be cleaned.

[0037] In step (4), heat is supplied to the rotary kiln to raise the temperature of the aggregate in the rotary kiln to a set temperature and to maintain the temperature, while the rotary kiln speed is controlled. Specifically, the temperature of the aggregate is raised to 130° C. to 150° C., and the holding time is controlled to be 60 min to 75 min. The temperature is raised and maintained to evaporate the water in the xanthan gum aqueous solution. The dehydrated xanthan gum is easily powdered and removed. Since it is bonded to the aggregate in a wet state, the xanthan gum carries the aggregate with it when powdered. In addition, the rotary kiln speed is increased to 3.5 r / min to 4.0 r / min. The higher speed causes the mixture of xanthan gum and aggregate on the inner wall of the rotary kiln and the outer wall of the return air pipe to fall off due to centrifugal action, thereby promoting the removal of the aggregate.

[0038] In step (5), whether to repeat steps (2) to (4) is determined based on the amount of aggregated material discharged from the kiln tail discharge end until the aggregated material on the inner wall of the rotary kiln and the outer wall of the return air duct is completely removed.

[0039] Figure 1A schematic diagram of the relevant structures of a method for cleaning the compacted material in a rotary kiln according to an embodiment of the present invention is shown. As shown in the figure, the rotary kiln body 3 is supported on a kiln head fixing seat 2 and a kiln tail fixing seat 6, and each of the kiln head fixing seat 2 and the kiln tail fixing seat 6 is provided with an observation port. The return air pipe 5 is evenly arranged along the circumference near the inner wall of the rotary kiln body 3, and the dust removal pipe 4 is provided on the kiln head fixing seat 2. A steel pipe 1 with multiple atomizing nozzles is placed into the rotary kiln body 3 through the observation ports of the kiln head fixing seat 2 and the kiln tail fixing seat 6 of the rotary kiln, and the extension range of the steel pipe 1 at the kiln head and the kiln tail substantially covers the entire axial range of the rotary kiln. A xanthan gum aqueous solution is sprayed onto the surface of the compacted material in the rotary kiln, and the rotary kiln body 3 is rotated so that the xanthan gum aqueous solution is sprayed over the entire circumferential range of the rotary kiln body 3.

[0040] The following is a specific experimental example of the method for cleaning the aggregated material in the rotary kiln according to the present invention. Unless otherwise specified, the raw materials and consumables used in the following examples can be obtained through conventional commercial means.

[0041] For the parts involving numerical ranges, those skilled in the art can select any value within the numerical range defined by the present invention according to actual needs, and are not limited to the numerical values ​​listed in the specific embodiments.

[0042] Experimental Example 1

[0043] After three months of operation, the thickness of the aggregate on the outer wall of the return air duct and the inner wall of the rotary kiln was 3-5 mm. The inner wall temperature of the rotary kiln was lowered to 50°C, the rotation speed was controlled at 0.7 r / min, and a xanthan gum solution with a mass concentration of 0.2% was sprayed onto the surface of the aggregate in the rotary kiln at a pressure of 0.4 MPa. The amount of xanthan gum solution was 2.1 kg / m 2 75% of the total amount was injected into the kiln head at the feed end, and 25% was injected into the kiln tail at the discharge end. The kiln was idling at 50°C for 100 minutes, then the temperature was raised to 130°C and maintained for 65 minutes. The rotary kiln speed was increased to 4.0 r / min. After repeating this three times, the observation hole at the kiln head was opened for observation. The plate-bound material on the inner wall of the rotary kiln and the return air pipe was basically completely detached.

[0044] Experimental Example 2

[0045] After four months of operation, the thickness of the aggregate on the outer wall of the return air duct and the inner wall of the rotary kiln was 5-8 mm. The inner wall temperature of the rotary kiln was lowered to 40-50 ° C, the rotation speed was controlled at 0.5 r / min, and a xanthan gum solution with a mass concentration of 0.23% was sprayed onto the surface of the aggregate in the rotary kiln at a pressure of 0.5 MPa. The amount of xanthan gum solution used each time was 1.9 kg / m 280% of the total amount of water was injected into the kiln head at the feed end, and 20% of the total amount was injected into the kiln tail at the discharge end. The rotary kiln was idling at a low temperature of about 40°C for 120 minutes, then the temperature was raised to 150°C and maintained for 75 minutes. After that, the rotary kiln speed was increased to 3.5 rpm. After repeating this process four times, the observation hole at the kiln head was opened for observation. The plate-bound material on the inner wall of the rotary kiln and the return air pipe was basically completely detached.

[0046] The above embodiments merely illustrate the implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for cleaning the plate-bound material in a rotary kiln, characterized in that: Include: (1) preparing a xanthan gum aqueous solution; (2) spraying the xanthan gum aqueous solution onto the surface of the plate-bound material in the rotary kiln; (3) Control the rotary kiln to run idle at low temperature for a predetermined time before heating up; (4) supplying heat to the rotary kiln to increase the temperature of the aggregate in the rotary kiln and keep it warm, while controlling the speed of the rotary kiln; (5) Determine whether to repeat steps (2) to (4) based on the amount of agglomerated material discharged from the kiln tail discharge end until the agglomerated material on the inner wall of the rotary kiln and the outer wall of the return air duct is completely removed.

2. The method for cleaning the compacted material in the rotary kiln according to claim 1, characterized in that: In step (1), the mass ratio of xanthan gum to water is 0.18% to 0.25%.

3. The method for cleaning the compacted material in the rotary kiln according to claim 1, characterized in that: In step (2), before spraying the xanthan gum aqueous solution into the rotary kiln, the temperature of the inner wall of the rotary kiln is controlled to be below 60°C.

4. The method for cleaning the compacted material in the rotary kiln according to claim 1, characterized in that: In step (2), before spraying the xanthan gum aqueous solution into the rotary kiln, the rotating speed of the rotary kiln is controlled to be 0.5 r / min to 0.8 r / min.

5. The method for cleaning the compacted material in the rotary kiln according to claim 1, characterized in that: In step (2), the xanthan gum solution is sprayed into the rotary kiln, which includes spraying the xanthan gum solution into the surface of the plate material in the rotary kiln at a pressure of 0.4 MPa to 0.5 MPa. The amount of the xanthan gum solution used each time is 1.8 kg / m 2 ~2.1kg / m 2 .

6. The method for cleaning the compacted material in the rotary kiln according to claim 5, characterized in that: In step (2), spraying the xanthan gum aqueous solution into the rotary kiln includes spraying the xanthan gum aqueous solution from the kiln head at the feed end and the kiln tail at the discharge end.

7. The method for cleaning the compacted material in the rotary kiln according to claim 6, characterized in that: Among them, 75% to 80% of the total amount is sprayed into the kiln head at the feeding end, and 20% to 25% of the total amount is sprayed into the kiln tail at the discharging end.

8. The method for cleaning the compacted material in the rotary kiln according to claim 1, characterized in that: In step (3), the temperature of low-temperature idling does not exceed 60° C., the rotation speed is controlled at 0.5 r / min to 0.8 r / min, and the rotation time is controlled at 100 min to 120 min.

9. The method for cleaning the compacted material in the rotary kiln according to claim 1, characterized in that: In step (4), the temperature of the slab material is raised to 130° C. to 150° C., the holding time is controlled at 60 min to 75 min, and the rotation speed of the rotary kiln is controlled at 3.5 r / min to 4.0 r / min.

10. The method for cleaning the compacted material in the rotary kiln according to claim 6, characterized in that: In step (2), the xanthan gum aqueous solution is sprayed into the rotary kiln using a steel pipe with multiple atomizing nozzles. The steel pipe is placed in the rotary kiln through the observation ports of the kiln head fixed seat and the kiln tail fixed seat of the rotary kiln, and the extension range of the steel pipe at the kiln head and the kiln tail is ensured to cover the entire axial range of the rotary kiln.

Images