阅读说明：本技术 一种玻纤用煅烧高岭土的生产方法 (Production method of calcined kaolin for glass fibers ) 是由 冯建明 陈建文 史兴顺 刘庆华 冯琦 刘松柏 于 2020-04-16 设计创作，主要内容包括：本发明公开了一种玻纤用煅烧高岭土的生产方法,包括以下步骤：1)将高岭土原料破碎、细破后研磨成200目以上的细粉,2)研磨后的细粉进入连续的旋风预热系统进行预热,预热温度为300～800℃,3)从旋风筒上部出来的粉料收集后与前述研磨后的粉料混合再一起进入旋风筒预热,从旋风筒下部出来的旋风下料进入煅烧设备进行煅烧,煅烧温度为500～900℃,煅烧停留时间10分钟以上,将煅烧结束的热粉冷却,即得玻纤用高岭土。本发明的玻纤用煅烧高岭土的生产方法,无需加入外加剂,降低了原料投入成本,制备的玻纤用高岭土COD在300ppm以下,且莫来石相极少,成分均匀,产品成分含量波动小,有利于玻纤的熔融拉丝,同时生产工艺容易实现连续化、大规模化生产。(The invention discloses a production method of calcined kaolin for glass fibers, which comprises the following steps: 1) crushing and finely crushing a kaolin raw material, grinding the crushed kaolin raw material into fine powder with the particle size of more than 200 meshes, 2) preheating the ground fine powder in a continuous cyclone preheating system at the preheating temperature of 300-800 ℃, 3) collecting the powder coming out of the upper part of a cyclone, mixing the powder with the ground powder, then preheating the mixture in the cyclone, feeding the cyclone discharged material coming out of the lower part of the cyclone into a calcining device for calcining at the calcining temperature of 500-900 ℃ for more than 10 minutes, and cooling the calcined hot powder to obtain the kaolin for glass fibers. The production method of the calcined kaolin for the glass fiber does not need to add additives, reduces the input cost of raw materials, ensures that the prepared kaolin for the glass fiber has COD (chemical oxygen demand) below 300ppm, has little mullite phase, uniform components and small fluctuation of the content of the components of the product, is beneficial to the melting and wire drawing of the glass fiber, and simultaneously has easy realization of continuous and large-scale production of the production process.)

1. The production method of the calcined kaolin for the glass fiber is characterized by comprising the following steps:

1) crushing and finely crushing kaolin raw materials, grinding the kaolin raw materials into fine powder with the particle size of more than 200 meshes,

2) the ground fine powder enters a continuous cyclone preheating system for preheating, the preheating temperature is 300-800 ℃,

3) the powder coming out of the upper part of the cyclone cylinder of the cyclone preheating system is mixed with the ground powder and then enters the cyclone cylinder for preheating,

and (3) feeding cyclone blanking coming out of the lower part of the cyclone into calcining equipment for calcining, wherein the calcining temperature is 500-900 ℃, the calcining retention time is more than 10 minutes, and cooling the calcined hot powder to obtain the kaolin for the glass fiber.

2. The method for producing calcined kaolin for glass fiber according to claim 1,

the working parameters of the cyclone preheating system are adjusted to control the powder coming out of the upper part of the cyclone to account for more than 10 percent of the total powder entering the cyclone.

3. The method for producing calcined kaolin for glass fiber according to claim 1,

the kaolin raw material comprises one or more of kaolin or kaolinite, and Al is mixed and compounded₂O₃Greater than 30% of SiO₂Less than 60% of Fe₂O₃The content of (A) is less than 0.7%, and the ignition loss is less than 25%, all in mass percentage.

4. The method for producing calcined kaolin for glass fiber according to claim 3,

the kaolin raw material comprises kaolin or kaolinite with the loss on ignition being more than 15.5%, and the proportion of the kaolin or the kaolinite with the loss on ignition being more than 15.5% in the total raw material of the kaolin is not less than 20%.

5. The method for producing calcined kaolin for glass fiber according to claim 4,

in the step 1), the crushing and fine crushing of the kaolin raw material comprises: respectively crushing different types of kaolin raw materials into small blocks with the size less than 100mm by adopting a jaw crusher or a hammer crusher, then mixing the small blocks according to a certain proportion and finely crushing the small blocks, wherein the finely crushing can be realized by adopting at least one of a double-roller crushing device, a hammer crushing device or a cone crushing device to finely crush the mixed small blocks into particle materials with the size less than 20mm, and then grinding the particle materials into fine powder with the size more than 200 meshes by adopting a grinder.

6. The method for producing calcined kaolin for glass fiber according to claim 1,

in the step 2), the continuous cyclone preheating system adopts 2-5-grade cyclone cylinders, and the preheating temperature is 300-800 ℃.

7. The method for producing calcined kaolin for glass fiber according to claim 6,

and a heat source of the cyclone preheating system is calcination tail gas of the calcination equipment.

8. The method for producing calcined kaolin for glass fiber according to claim 7,

after preheating, the ignition loss of the powder is reduced to below 5 percent.

9. The method for producing calcined kaolin for glass fiber according to any one of claims 1 to 8, characterized in that,

the calcination temperature is 500-900 ℃, and the calcination retention time is 10-60 minutes.

Technical Field

The invention relates to the technical field of inorganic materials, in particular to a production method of calcined kaolin for glass fibers.

Background

Glass fiber originates from the United states, emerges in the 30 th 20 th century, is a substitute material with excellent performance, and is applied to substitute materials such as steel, plates, base materials and the like in different fields. China has own glass fiber industry probably in the 1950 s, the whole industry has developed and perfected a whole industry chain system, and the glass fiber and glass fiber products to glass fiber composite materials are a relatively complete manufacturing industry chain. From the global data, the global glass fiber yield and the Chinese yield percentage in 2009-2018 both keep rising trend, the global glass fiber yield in 2018 is 770 ten thousand tons, and the Chinese yield percentage reaches 58.4%.

Kaolin is one of the important raw materials of the glass fiber, and the Kaolin mainly provides Al in the glass fiber₂O₃And SiO₂The dosage of the kaolin can account for one third of the batch, but the kaolin for the glass fiber in China is always occupied by imported products in the high-end market. Kaolin distributed in southeast and southeast provinces of China has good plasticity, belongs to halloysite, is easy to absorb moisture, is easy to form caking and is not suitable for pneumatic transmission due to long storage time for a tank furnace wire drawing production line with high automation degree, and kaolin suitable for glass fiber production is mainly distributed in a carboniferous-diadskin coal system in northeast and northwest of China, and is hard kaolin deposited by gangue inclusion, a top plate or a single ore bed in a coal bed, which is also called coal-series kaolin. The largest producing area of the high-quality sedimentary kaolin is the same area in Shanxi, and also some areas such as Shandong, Shanxi, Hebei, inner Mongolia and the like. The kaolin belongs to hard kaolin, has no plasticity, can not absorb moisture, has stable aluminum content, but contains more carbon-containing substances such as organic matters and the like in coal gangue, and is extremely unfavorable for clarifying glass fibers, particularly high-grade glass fiber molten liquid. In the industry, the content of raw material organic matters is expressed by a COD (chemical oxygen demand) value, the higher the COD is, the higher the content of the organic matters is, and the COD of untreated coal gangue is generally over thousands of ppm. At present, domestic manufacturers calcine coal gangue to obtain glassThe kaolin for fiber uses, but COD is more than 300ppm, and has a difference with 300ppm index of the advanced products of foreign products. The common calcining equipment such as a rotary kiln is not particularly ideal for contacting materials with air, and COD is difficult to be reduced to below 300ppm in a low-temperature state; the COD can be reduced by raising the temperature, but the hidden trouble brought by high temperature is that the mullite content in the product is high. There is a gap between domestic products and foreign products in that the quality of the products is unstable, the difference between the alumina content of the materials above and below the same batch sometimes exceeds 0.8%, and the difference between the alumina content of the products in different batches sometimes is larger. Raw materials with unstable quality can cause serious broken wire and flying wire in the wire drawing operation, and cause serious economic loss for glass fiber factories.

Disclosure of Invention

The invention provides a production method of calcined kaolin for glass fibers, which aims to solve the technical problems of high COD (chemical oxygen demand) value or high mullite phase content and unstable quality of kaolin for glass fibers prepared from coal-series kaolin with high carbon content.

According to one aspect of the present invention, there is provided a method for producing calcined kaolin for glass fibers, comprising the steps of:

1) crushing and finely crushing kaolin raw materials, grinding the kaolin raw materials into fine powder with the particle size of more than 200 meshes,

2) the ground fine powder enters a continuous cyclone preheating system for preheating, the preheating temperature is 300-800 ℃,

3) the powder coming out of the upper part of the cyclone cylinder of the cyclone preheating system is mixed with the ground powder and then enters the cyclone cylinder for preheating,

and (3) feeding cyclone blanking coming out of the lower part of the cyclone into calcining equipment for calcining, wherein the calcining temperature is 500-900 ℃, the calcining retention time is more than 10 minutes, and cooling the calcined hot powder to obtain the kaolin for the glass fiber.

Furthermore, the working parameters of the cyclone preheating system are adjusted to control the powder coming out of the upper part of the cyclone to account for more than 10 percent of the total powder entering the cyclone.

Further, the kaolin raw material comprises one or more of kaolin or kaolinite, and Al is mixed and compounded₂O₃Is in large amountAt 30%, SiO₂Less than 60% of Fe₂O₃The content of (A) is less than 0.7%, and the ignition loss is less than 25%, all in mass percentage.

Further, the kaolin raw material comprises kaolin or kaolinite with the loss on ignition being more than 15.5%, and the proportion of the kaolin or the kaolinite with the loss on ignition being more than 15.5% in the total kaolin raw material is not less than 20%.

Further, in the step 1), different types of kaolin raw materials are respectively crushed into small blocks with the size smaller than 100mm by adopting a jaw crusher or a hammer crusher, then the small blocks are mixed according to a certain proportion and then finely crushed, the fine crushing can adopt at least one of a double-roller crushing device, a hammer crushing device or a cone crushing device to finely crush the mixed small blocks into particle materials with the size smaller than 20mm, and then the particle materials are ground into fine powder with the size larger than 200 meshes by adopting a grinder.

Further, in the step 2), the continuous cyclone preheating system adopts 2-5-grade cyclone cylinders, and the preheating temperature is 300-800 ℃.

Further, a heat source of the cyclone preheating system is calcination tail gas of the calcination equipment.

Further, after preheating, the loss on ignition of the powder is reduced to below 5%.

Further, the fine powder coming out of the upper part of the cyclone is collected by a bag-type dust collector.

Further, the calcination temperature is 500-900 ℃, and the calcination retention time is 10-60 minutes.

The invention has the following beneficial effects:

the invention relates to a method for producing glass fiber calcined kaolin, which comprises the steps of crushing kaolin raw materials into lump materials, further crushing the lump materials into particle materials, grinding the particle materials into fine powder with the particle size of more than 200 meshes by grinding equipment, preheating the ground fine powder in a continuous cyclone preheating system to remove most of carbon and moisture, greatly reducing COD, dynamically mixing the fine powder in a multistage continuous preheating cyclone cylinder to ensure that the chemical components of the fine powder are more uniform and stable, enabling coarse powder separated by the cyclone cylinder to fall into the calcining equipment from the lower part for calcining, collecting and returning part of decarburized powder on the upper part of the cyclone cylinder after being separated from air flow, mixing the collected powder with the ground fine powder, then preheating the mixture in the cyclone cylinder, mixing the preheated and decarburized fine powder with non-decarburized fine powder, then feeding the mixture into the cyclone cylinder, and greatly diluting the heat discharged by the latter in the decarburizing, greatly improving the local overheating condition, so that the product contains little or no mullite phase; the material discharged from the lower part of the cyclone cylinder enters the calcining equipment for calcining, the COD is further reduced to more than 300, the phenomenon of local overheating can not occur because most of carbon is removed in the preheating process, and the calcining temperature is within 900 ℃, so that the mullite phase is not easy to form in the calcining process. In addition, most COD is removed by preheating in the early stage, and the later-stage calcination retention time can be shorter, so that the yield can be improved, and the energy consumption and the production cost can be reduced.

The kaolin (rock) can be hard kaolin, semi-hard kaolin, such as coal gangue, white ore, purple wood knot and the like which are common in the north.

The production method of the calcined kaolin for the glass fiber does not need to add an additive, reduces the input cost of raw materials, ensures that the prepared kaolin for the glass fiber has the COD of less than 300, has little mullite phase and uniform components, and has Al₂O₃The content fluctuation range is +/-0.4 percent, and SiO₂The content fluctuation range is +/-0.4%, the melting and wire drawing of the glass fiber are facilitated, and the continuous and large-scale production of the production process is easy to realize.

In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic flow chart of a method for producing calcined kaolin for glass fiber according to a preferred embodiment of the present invention;

FIG. 2 is an X-ray diffraction pattern of calcined kaolin for glass fiber according to example 1 of the present invention;

FIG. 3 is an X-ray diffraction pattern of the calcined kaolin of comparative example 1 of the present invention.

Detailed Description

The embodiments of the invention will be described in detail below with reference to the accompanying drawings, but the invention can be embodied in many different forms, which are defined and covered by the following description.

As shown in fig. 1, the method for producing calcined kaolin for glass fiber according to the present invention comprises the following steps:

1) crushing and finely crushing kaolin raw materials, grinding the kaolin raw materials into fine powder with the particle size of more than 200 meshes,

2) the ground fine powder enters a continuous cyclone preheating system for preheating, the preheating temperature is 300-800 ℃,

3) the powder coming out of the upper part of the cyclone cylinder of the cyclone preheating system is mixed with the ground powder and then enters the cyclone cylinder for preheating,

and (3) feeding cyclone blanking coming out of the lower part of the cyclone into calcining equipment for calcining, wherein the calcining temperature is 500-900 ℃, the calcining retention time is more than 10 minutes, and cooling the calcined hot powder to obtain the kaolin for the glass fiber.

According to the production method of the calcined kaolin for the glass fiber, the kaolin raw material is crushed into lump materials, then the lump materials are further crushed into particle materials and then enter ore grinding equipment to be ground into fine powder with the particle size of more than 200 meshes, preferably 200-1250 meshes, more preferably 300-500 meshes, most of carbon and moisture in the ground fine powder are removed through preheating in a continuous cyclone preheating system, COD is greatly reduced, the preheating temperature is 300-800 ℃, and because the carbon content in the raw material is high, a large amount of heat is generated during preheating and decarbonization, even combustion occurs, and a large amount of mullite phase is generated due to local overheating, the preheating temperature is not too high, but if the preheating temperature is too low, the decarbonization and dehydration effects are not ideal, and the COD is still high; the fine powder is dynamically mixed in a multistage continuous cyclone, so that the chemical components of the fine powder are more uniform and stable, the coarse powder separated by the cyclone falls into a calcining device from the lower part for calcining, the partially decarburized powder on the upper part of the cyclone is separated from airflow, collected and returned, mixed with the ground fine powder and then enters the cyclone for preheating, and the preheated and decarburized powder and the powder without decarburization are mixed and then enter the cyclone, so that the heat emitted by the powder without decarburization in the decarburization process is greatly diluted by the fine powder, the local overheating condition is greatly improved, and the mullite phase is less or not contained in the product; the material discharged from the lower part of the cyclone cylinder enters the calcining equipment for calcining, the COD is further reduced to more than 300, the phenomenon of local overheating can not occur because most of carbon is removed in the preheating process, and the calcining temperature is within 900 ℃, so that the mullite phase is not easy to form in the calcining process. Preferably, the calcination temperature is 500-900 ℃, and the calcination retention time is 10-60 minutes. Under the condition of the calcination temperature and the calcination retention time, the COD of the kaolin product can reach the standard without generating a mullite phase.

The production method of the calcined kaolin for the glass fiber does not need to add additives, reduces the input cost of raw materials, ensures that the COD of the prepared kaolin for the glass fiber is below 300ppm and reaches the international advanced level, and has extremely little mullite phase, uniform components and Al₂O₃The content fluctuation range is +/-0.4 percent, and SiO₂The content fluctuation range is +/-0.4%, the melting and wire drawing of the glass fiber are facilitated, and the continuous and large-scale production of the production process is easy to realize.

In the invention, the working parameters of the cyclone preheating system are adjusted to control the powder coming out of the upper part of the cyclone to account for more than 10 percent of the total powder entering the cyclone. The fine powder on the upper part of the cyclone cylinder which is partially decarburized is separated from the airflow, collected and returned, mixed with the ground fine powder and then enters the cyclone cylinder for preheating, the preheated decarburized powder and the powder which is not decarburized enter the cyclone cylinder together, the preheated decarburized powder and the powder which is not decarburized greatly dilute the heat emitted by the powder in the decarburizing process, the local overheating condition is improved, the mullite phase is avoided from being formed, if the amount of the returned fine powder is too small, the effect of the dilution heat is not obvious, and therefore the proportion of the upper discharge powder can be adjusted by adjusting the air volume and the air speed of a. If the amount of the returned powder is too much, the production efficiency is reduced, so that the proportion of the returned powder is preferably controlled to be 10-20%.

In the invention, the kaolin raw material comprises one or more of kaolin or kaolinite, and Al is mixed and compounded₂O₃Greater than 30% of SiO₂Less than 60% of Fe₂O₃The content of (A) is less than 0.7%, and the ignition loss is less than 25%, all in mass percentage. The kaolin raw material can be selected from kaolin or kaolinite with different grades in different producing areas, the raw material source is convenient, and the compounding of various different raw materials needs to ensure that Al is mixed and compounded₂O₃Greater than 30% of SiO₂Less than 60% of Fe₂O₃The content of the kaolin is less than 0.7 percent, and the ignition loss is less than 25 percent, so that the kaolin produced can meet the application requirements of the glass fiber industry. The coal gangue and the lignum sappan are widely used kaolin (rock), and the kaolin raw material can be selected from the coal gangue and/or the lignum sappan.

In the invention, the kaolin raw material comprises kaolin or kaolinite with the loss on ignition being more than 15.5 percent, and the proportion of the kaolin or the kaolinite with the loss on ignition being more than 15.5 percent in the total raw material of the kaolin is not less than 20 percent. The high loss on ignition material has a relatively high moisture content and consumes a relatively high amount of heat during preheating, thereby reducing the risk of overheating, and therefore the kaolin raw material preferably comprises a proportion of the high loss on ignition material. In order to ensure the effect, the ignition loss is more preferably more than 18%.

In the invention, in the step 1), the crushing and fine crushing of the kaolin raw material comprises: respectively crushing different types of kaolin raw materials into small blocks with the size less than 100mm by adopting a jaw crusher or a hammer crusher, then mixing the small blocks according to a certain proportion and finely crushing the small blocks, wherein the finely crushing can be realized by adopting at least one of a double-roller crushing device, a hammer crushing device or a cone crushing device to finely crush the mixed small blocks into particle materials with the size less than 20mm, and then grinding the particle materials into fine powder with the size more than 200 meshes by adopting a grinder. Since only a single kind of raw material is used, it may be difficult to satisfy Al in the raw material₂O₃Greater than 30% of SiO₂Less than 60% of Fe₂O₃The content of (A) is less than 0.7%, and the ignition loss is less than 25%, so that various raw materials with different tastes are required to be used in combination. Mixing different kinds of kaolinThe soil raw materials are respectively crushed into small blocks, and then the small blocks are mixed and then are finely crushed and ground, so that the homogenization of the materials is facilitated, the components of the raw materials are more stable, and the quality of the obtained product is more stable.

In the invention, in the step 2), a 2-5-grade cyclone cylinder is adopted in the continuous cyclone preheating system, and the preheating temperature is 300-800 ℃. The more the progression of whirlwind system of preheating, the compounding effect is better, and product quality is more stable, but the many equipment investment of progression is just big, considers the investment cost performance, sets up whirlwind system of preheating into 2 ~ 5 grades, makes the COD after preheating reduce more.

In the invention, the heat source of the cyclone preheating system is the calcining tail gas of the calcining equipment. The waste heat of the calcining tail gas of the calcining equipment is used as the heat source of the cyclone preheating system, so that the heat utilization rate is improved, and the energy consumption is reduced.

In the invention, after preheating, the ignition loss of the powder is reduced to below 5 percent. The loss on ignition of the preheated powder is controlled to be below 5%, on one hand, the phenomenon of local overheating caused by removal of a large amount of carbon can be avoided during subsequent calcination, the mullite phase is avoided, on the other hand, COD (chemical oxygen demand) after calcination can be below 300, on the other hand, the loss on ignition of the returned fine powder is low, and after the fine powder is mixed with the ground fine powder, the effect of preventing local overheating by diluting heat generated by a large amount of decarburization during preheating is better.

In the invention, the fine powder from the upper part of the cyclone is collected by adopting a bag-type dust collector. The fine powder discharged from the upper part of the cyclone cylinder is carried by airflow and passes through the bag-type dust remover, the fine powder is collected after being intercepted by a bag and returns to be uniformly mixed with the fine powder ground by the grinding machine, and then the fine powder and the fine powder enter the cyclone preheating system together, and the clean airflow after the bag-type dust removal can be emptied and can be used for other secondary utilization.

The following examples are provided to further illustrate the production method of the calcined kaolin for glass fiber of the present invention.