A Kiln Lining Drying Technology and Application of a Whole-Pour Rotary Kiln

Abstract

The present invention relates to the technical field of rotary kiln treatment of hydrometallurgical zinc slag. Its purpose is to provide a kiln drying process and application for a monolithic cast rotary kiln lining. The process comprises two stages: a first stage for curing and drying the monolithic cast kiln lining, and a second stage for heating and drying the monolithic cast kiln lining. After the monolithic cast kiln lining is completed, the kiln lining molds are completely removed, and a 1-3 cm thick layer of rice straw is laid on the kiln lining surface. The kiln lining is sprayed with atomized water every 6-12 hours. After the water spraying, the rotary kiln is rotated half a revolution to prevent rapid water loss and cracking of the kiln lining. The kiln lining is naturally cured and air-dried for approximately 5-7 days, after which the naturally air-dried kiln lining is heated and dried. By designing the heating process for the monolithic cast kiln lining, the present invention controls the expansion rate of the rotary kiln lining, thereby extending the life of the rotary kiln lining and improving the kiln's operating rate and equipment utilization.

Description

Technical Field

[0001] The invention belongs to the technical field of treating wet zinc smelting slag in a rotary kiln, and particularly relates to a kiln lining drying process and application of a monolithic cast rotary kiln. Background Art

[0002] The rotary kiln is an important production equipment in the building materials, nonferrous metals, metallurgy and other industries. It is mainly composed of a transmission system, a kiln shell, and a kiln lining. The kiln lining mainly includes separate and close-stacked refractory brick kiln linings and integrally cast kiln linings. Separate and close-stacked refractory brick kiln linings have slippage displacement in the mortar joints, resulting in a short service life of the separate and close-stacked refractory kiln lining, generally around 6 months. The integrally cast kiln lining of amorphous refractory materials has gradually been widely used in rotary kiln linings due to its advantages such as long effective operating cycle, low maintenance rate, high equipment utilization rate, low cost, and good environmental benefits. Since the integrally cast kiln lining of amorphous refractory materials is pre-rotary kiln-bonded through integral casting technology, the kiln drying quality of the rotary kiln directly affects the performance of the kiln lining. Summary of the Invention

[0003] The purpose of the present invention is to provide a kiln lining baking process and application of a monolithic cast rotary kiln to solve the problems raised in the above background technology.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A kiln lining baking process for a cast-in-place rotary kiln includes the following two stages:

[0006] The first stage is the curing and drying stage of the integrally cast kiln lining: This stage is the natural curing and air-drying stage of the integrally cast kiln lining. After the integral casting of the kiln lining is completed, all the kiln lining molds are removed and 1 to 3 cm thick rice straw is laid on the surface of the kiln lining. The kiln lining is sprayed with atomized water every 6 to 12 hours. After spraying water, the rotary kiln is rotated 1 / 2 a circle to prevent the kiln lining from losing water too quickly and causing cracking. After the kiln lining is naturally cured and air-dried for about 5 to 7 days, the next stage of heating and drying the kiln can be carried out.

[0007] The second stage is the heating and kiln baking stage for integral casting of the furnace lining: the naturally air-dried kiln lining is heated and baked. During the heating and kiln baking process, the pressure at the kiln tail is maintained at 40-60 Pa. The kiln temperature is raised from room temperature to 110°C at a rate of 3-4°C / h, which takes about 30 hours. When the kiln tail temperature rises to 110°C, it is kept at a constant temperature for 24 hours. When the kiln tail temperature rises from 110°C to 200°C, it is raised at a rate of 4-5°C / h for about 18 hours. When the kiln tail temperature rises to 200°C, it is kept at a constant temperature for 24 hours. When the temperature at the kiln tail rises from 200℃ to 350℃, it is heated at a rate of 5-6℃ / h, which takes about 30 hours; when the temperature at the kiln tail reaches 350℃, it is kept constant at this temperature for 24 hours; when the temperature at the kiln tail rises from 350℃ to 500℃, it is heated at a rate of 6-7℃ / h, which takes about 25 hours; when the temperature at the kiln tail rises to 500℃, it is kept constant at this temperature for 16 hours; when the temperature at the kiln tail rises from 500℃ to 600℃, it is heated at a rate of 7-8℃ / h, which takes about 12 hours; when the temperature at the kiln tail rises to 600℃, the materials are put into production.

[0008] When the temperature at the kiln tail rises from room temperature to 250°C, the kiln rotates, and the kiln rotates 1 / 4 of a circle per hour.

[0009] When the temperature at the kiln tail rises from 250° C. to 350° C., the rotary kiln rotates slowly continuously.

[0010] When the temperature at the kiln tail is above 350° C., the kiln main motor is started to rotate the kiln, and the kiln speed is adjusted as needed.

[0011] When the temperature at the kiln tail reaches 350°C, a small amount of coking coal is added according to the situation, and the kiln lining water spraying and slag flushing water are started at the same time.

[0012] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0013] The present invention controls the expansion rate of the rotary kiln lining by designing the integral casting kiln lining drying and heating process, thereby extending the service life of the rotary kiln lining and improving the rotary kiln start-up rate and equipment utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 1 is a kiln temperature rise curve diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention but are not intended to limit the present invention.

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0018] Example 1

[0019] After the integral pouring of the rotary kiln's refractory lining is completed according to the whole pouring plan, 2 cm thick rice straw is laid on the lining and the straw is sprayed with water for maintenance every 12 hours. The rotary kiln rotates half a circle after each water spraying. This operation is repeated for 7 days until the rotary kiln's lining is completely dry and solidified.

[0020] After the lining of the rotary kiln is cured at room temperature, the kiln lining is baked with firewood (or natural gas, diesel, heavy oil and other fuels). During the baking process, the blower and induced draft fan are kept on, and the pressure at the kiln tail is kept at about 50Pa. According to the heating curve, by controlling the blast volume, the temperature at the rotary kiln tail is kept at a heating rate of 3℃ / h to 110℃ for about 30 hours. After the temperature is raised to 110℃, it is kept warm for 24 hours. During the insulation period, the temperature fluctuation at the kiln tail does not exceed ±5℃. After the insulation is completed, the blast volume and the amount of fuel added are continued to be adjusted to make the kiln tail heat up to 200℃ at a heating rate of 4℃ / h. It takes about 20 hours. After the temperature is raised to 200℃, it is kept warm for 24 hours. During the insulation period, the temperature at the kiln tail is kept warm. The fluctuation shall not exceed ±5℃; after the insulation is completed, adjust the air volume and fuel quantity to increase the temperature at the kiln tail to 350℃ at a heating rate of 5℃ / h, and then keep it warm for 24 hours; after the insulation is completed, continue to adjust the air volume and fuel quantity to increase the temperature at the kiln tail to 500 degrees Celsius at a heating rate of 6℃ / h, and then keep it warm for 16 hours; after the insulation is completed, adjust the fuel quantity and air volume to increase the temperature at the kiln tail to 600 degrees Celsius at a heating rate of 7℃ / h, and then keep it warm for 18 hours before starting material production.

[0021] When the temperature at the kiln tail rises from room temperature to 250℃, the kiln is rotated, and the kiln is rotated 1 / 4 of a circle per hour;

[0022] When the temperature at the kiln tail rises from 250℃ to 350℃, the rotary kiln rotates slowly continuously;

[0023] When the temperature at the kiln tail is above 350℃, start the kiln main motor to rotate the kiln and adjust the kiln speed as needed.

[0024] When the temperature at the kiln tail reaches 350℃, a small amount of coking coal is added according to the situation, and the kiln lining water spraying and slag flushing water are started at the same time.

[0025] From the time the rotary kiln was put into production to the time it was overhauled, the lining of the rotary kiln was used for 18 months without any falling off or cracking, which is 10 months longer than the lining of a brick-type rotary kiln.

[0026] Example 2

[0027] After the integral pouring of the rotary kiln's refractory lining is completed according to the whole pouring plan, 3 cm thick rice straw is laid on the lining and the straw is sprayed with water for curing every 6 hours. The rotary kiln rotates half a circle after each water spraying. This operation is repeated for 5 days until the rotary kiln's lining is completely dry and solidified.

[0028] After the lining of the rotary kiln is cured at room temperature, the kiln lining is baked with firewood (or natural gas, diesel, heavy oil and other fuels). During the baking process, the blower and induced draft fan are kept on, and the pressure at the kiln tail is kept at about 40Pa. According to the heating curve, by controlling the blast volume, the temperature at the tail of the rotary kiln is kept at a heating rate of 4℃ / h to 110℃ for about 30 hours. After the temperature is raised to 110℃, it is kept warm for 24 hours. During the insulation period, the temperature fluctuation at the kiln tail does not exceed ±5℃. After the insulation is completed, the blast volume and the amount of fuel added are continued to be adjusted to make the kiln tail heat up to 200℃ at a heating rate of 5℃ / h for about 20 hours. After the temperature is raised to 200℃, it is kept warm for 24 hours. During the insulation period, the temperature at the kiln tail is kept warm. The fluctuation shall not exceed ±5℃; after the insulation is completed, adjust the air volume and fuel quantity to increase the temperature at the kiln tail to 350℃ at a heating rate of 6℃ / h, and then keep it warm for 24 hours; after the insulation is completed, continue to adjust the air volume and fuel quantity to increase the temperature at the kiln tail to 500 degrees Celsius at a heating rate of 7℃ / h, and then keep it warm for 16 hours; after the insulation is completed, adjust the fuel quantity and air volume to increase the temperature at the kiln tail to 600 degrees Celsius at a heating rate of 8℃ / h, and then keep it warm for 18 hours before starting material production.

[0029] When the temperature at the kiln tail rises from room temperature to 250℃, the kiln is rotated, and the kiln is rotated 1 / 4 of a circle per hour;

[0030] When the temperature at the kiln tail rises from 250℃ to 350℃, the rotary kiln rotates slowly continuously;

[0031] When the temperature at the kiln tail is above 350℃, start the kiln main motor to rotate the kiln and adjust the kiln speed as needed.

[0032] When the temperature at the kiln tail reaches 350℃, a small amount of coking coal is added according to the situation, and the kiln lining water spraying and slag flushing water are started at the same time.

[0033] From the time the rotary kiln was put into production to the time it was overhauled, the lining of the rotary kiln was in use for 15 months without any peeling or cracking, which is 8 months longer than the lining life of a brick-type rotary kiln.

[0034] Example 3

[0035] After the integral pouring of the rotary kiln's refractory lining is completed according to the whole pouring plan, 2 cm thick rice straw is laid on the lining and the straw is sprayed with water for curing every 8 hours. The rotary kiln rotates half a circle after each water spraying. This operation is repeated for 6 days until the rotary kiln's lining is completely dry and solidified.

[0036] After the lining of the rotary kiln is cured at room temperature, the kiln lining is baked with firewood (or natural gas, diesel, heavy oil and other fuels). During the baking process, the blower and induced draft fan are kept on, and the pressure at the kiln tail is kept at about 60Pa. According to the heating curve, by controlling the blast volume, the temperature at the tail of the rotary kiln is kept at a heating rate of 3℃ / h to 110℃ for about 30 hours. After the temperature is raised to 110℃, it is kept warm for 24 hours. During the insulation period, the temperature fluctuation at the tail of the kiln does not exceed ±5℃. After the insulation is completed, the blast volume and the amount of fuel added are continued to be adjusted to make the tail of the kiln heated to 200℃ at a heating rate of 4℃ / h for about 20 hours. After the temperature is raised to 200℃, it is kept warm for 24 hours. During the insulation period, the temperature fluctuation at the tail of the kiln does not exceed ±5℃. The temperature fluctuation does not exceed ±5℃; after the insulation is completed, adjust the blast volume and fuel quantity to increase the temperature at the kiln tail to 350℃ at a heating rate of 6℃ / h, and then keep it warm for 24 hours; after the insulation is completed, continue to adjust the blast volume and fuel quantity to increase the temperature at the kiln tail to 500℃ at a heating rate of 6℃ / h, and then keep it warm for 16 hours; after the insulation is completed, adjust the fuel quantity and blast volume to increase the temperature at the kiln tail to 600℃ at a heating rate of 7℃ / h, and then keep it warm for 18 hours before feeding and production can be carried out.

[0037] When the temperature at the kiln tail rises from room temperature to 250℃, the kiln is rotated, and the kiln is rotated 1 / 4 of a circle per hour;

[0038] When the temperature at the kiln tail rises from 250℃ to 350℃, the rotary kiln rotates slowly continuously;

[0039] When the temperature at the kiln tail is above 350℃, start the kiln main motor to rotate the kiln and adjust the kiln speed as needed.

[0040] When the temperature at the kiln tail reaches 350℃, a small amount of coking coal is added according to the situation, and the kiln lining water spraying and slag flushing water are started at the same time.

[0041] From the time the rotary kiln was put into production to the time it was overhauled, the lining of the rotary kiln was in use for 20 months without any peeling or cracking, which is 12 months longer than the lining of a brick-type rotary kiln.

Claims

1. A kiln lining baking process for a cast-in-place rotary kiln, characterized in that: It includes the following two stages: The first stage is the curing and drying stage of the integrally cast kiln lining: This stage is the natural curing and air-drying stage of the integrally cast kiln lining. After the integral casting of the kiln lining is completed, all the kiln lining molds are removed and 1 to 3 cm thick rice straw is laid on the surface of the kiln lining. The kiln lining is sprayed with atomized water every 6 to 12 hours. After spraying water, the rotary kiln is rotated 1 / 2 a circle to prevent the kiln lining from losing water too quickly and causing cracking. After the kiln lining is naturally cured and air-dried for 5 to 7 days, the next stage of heating and drying the kiln can be carried out. The second stage is the heating and kiln baking stage of the integral casting furnace lining: the naturally air-dried kiln lining is heated and baked. During the heating and kiln baking process, the kiln tail pressure is maintained at 40-60Pa, and the kiln temperature is raised from room temperature to 110℃ at a rate of 3-4℃ / h for 30 hours; when the kiln tail temperature rises to 110℃, it is kept at a constant temperature for 24 hours; when the kiln tail temperature rises from 110℃ to 200℃, it is raised at a rate of 4-5℃ / h for 18 hours; when the kiln tail temperature rises to 200℃, it is kept at a constant temperature for 24 hours. h; when the temperature at the kiln tail rises from 200℃ to 350℃, increase the temperature at a rate of 5-6℃ / h for 30 hours; when the temperature at the kiln tail reaches 350℃, keep the temperature constant for 24 hours; when the temperature at the kiln tail rises from 350℃ to 500℃, increase the temperature at a rate of 6-7℃ / h for 25 hours; when the temperature at the kiln tail rises to 500℃, keep the temperature constant for 16 hours; when the temperature at the kiln tail rises from 500℃ to 600℃, increase the temperature at a rate of 7-8℃ / h for 12 hours; when the temperature at the kiln tail rises to 600℃, start production; When the temperature at the kiln tail rises from room temperature to 250°C, the kiln is rotated, and the kiln is rotated 1 / 4 of a turn per hour; When the temperature at the kiln tail rises from 250°C to 350°C, the rotary kiln rotates slowly continuously; When the temperature at the kiln tail is above 350°C, the kiln main motor is started to rotate the kiln, and the kiln speed is adjusted as needed; When the temperature at the kiln tail reaches 350°C, a small amount of coking coal is added according to the situation, and the kiln lining water spraying and slag flushing water are started at the same time.

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