CN111792917A

CN111792917A - Method for preparing artificial expanded vermiculite from fly ash

Info

Publication number: CN111792917A
Application number: CN202010717013.6A
Authority: CN
Inventors: 姚长青; 徐顺涛; 刘纯杰
Original assignee: Shandong Yike Energy Saving Technology Co ltd
Current assignee: Shandong Yike Energy Saving Technology Co ltd
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2020-10-20

Abstract

The invention provides a method for preparing artificial expanded vermiculite by using fly ash. The method comprises the following steps: taking specific amounts of fly ash, feldspar and auxiliary materials, and crushing to 20-100 meshes; sending the mixture into a Raymond mill for dry grinding, and then air-selecting particles with the particle size of less than 200 meshes to obtain powder; putting the obtained powder and a specific amount of pore-forming agent into a mixer, mixing the materials by a dry method, and humidifying the materials until the water content is 4-10%; then conveying the blank to an automatic press to be pressed into a semi-finished product with the thickness of 10-50 mm; and then sintering is carried out. The invention produces a natural vermiculite substitute product by utilizing tailings and industrial solid wastes in an artificial synthesis mode, solves the storage problem of feldspar-like tailings and industrial solid wastes, and also solves the problem of vermiculite shortage of mines caused by sealing mountains, cultivating forests and resource exhaustion. The invention ensures the porosity, water absorption, activity and strength of the artificial expanded vermiculite by a special processing technology, a reasonable formula and a firing method.

Description

Method for preparing artificial expanded vermiculite from fly ash

Technical Field

The invention relates to the technical field of production processes of inorganic non-metallic materials, in particular to a method for preparing artificial expanded vermiculite by using fly ash.

Background

The vermiculite is a magnesium-containing aluminosilicate secondary metamorphic mineral with a layered structure, can expand by 6-20 times rapidly after being roasted at high temperature, and has very strong heat preservation and heat insulation performance. The expanded vermiculite is laid on the roof, so that a good heat insulation effect can be achieved, and the building is warm in winter and cool in summer. The partition wall board of high-rise building built by vermiculite bricks can play roles of sound insulation, fire prevention, moisture prevention and the like, and can also reduce the load of the building body.

The expanded vermiculite can be used as a seed preservative, a soil conditioner, a wetting agent and a plant growth agent to be used in a greenhouse, has the characteristics of loose soil, good air permeability, strong water absorption, small temperature change and the like, is beneficial to the growth of crops, and can reduce the input of fertilizers. In the newly emerging soilless culture technology, it is an indispensable raw material.

In view of the above characteristics of expanded vermiculite, our artificial expanded vermiculite must have high porosity, high water absorption, and high activity. It must have a certain strength and must not be broken during transportation and weathered after water exposure.

The fly ash is used as one of the current industrial waste residues with large discharge amount in China, and is mainly generated and collected from coal-fired flue gas of a thermal power plant. The fly ash mainly comprises silicon dioxide, aluminum oxide, calcium oxide, ferric oxide, titanium oxide and the like, and simultaneously contains a small amount of vitreous body and a trace amount of unburned carbon, and because the volume-weight ratio of the fly ash is light, the fly ash is easy to form raised dust and is not easy to store, and simultaneously is easy to pollute soil and damage the environment. The storage and the production amount of the fly ash are huge, how to comprehensively utilize the fly ash, realize the industrial production and change waste into valuable is a very important problem for production and manufacturing enterprises, and the fly ash mainly has the following purposes according to different standards at present: the method comprises the steps of firstly, using the cement as a cement filler to prepare high-grade concrete, secondly, producing cement aerated building blocks, and thirdly, producing micro-beads, floating beads, preparing heat insulation materials and fillers, and the like. According to the component analysis of the fly ash, the glass phase component is added, and the dry process technologies of mixing, grinding, distributing, sintering, crushing and the like can be used for producing the artificial expanded vermiculite.

The fly ash is used for preparing the artificial expanded vermiculite, and the fly ash is mainly coal series kaolin, so that the fire resistance is high, and the artificial expanded vermiculite is not easy to sinter. In order to make the artificial expanded vermiculite have high porosity, high water absorption and high activity, a pore-forming agent and a fluxing agent are required to be added, the pore-forming agent is easy to reduce the strength of the artificial expanded vermiculite, and the fluxing agent can increase the strength of the artificial vermiculite and simultaneously reduce the activity of the artificial vermiculite.

Disclosure of Invention

The invention aims to provide a method for preparing artificial expanded vermiculite by using fly ash aiming at the technical defects of the prior art, so as to solve the technical problem that the conventional process is difficult to simultaneously consider porosity, water absorption, activity and strength.

The invention also aims to solve the technical problem that the artificial expanded vermiculite is not easy to sinter when prepared from the fly ash.

The invention aims to solve the technical problem of how to expand the resource utilization method of the fly ash.

In order to achieve the technical purpose, the invention adopts the following technical scheme:

the method for preparing the artificial expanded vermiculite by using the fly ash comprises the following steps:

1) taking 30-70 parts by weight of fly ash, 15-50 parts by weight of feldspar and 2-8 parts by weight of auxiliary materials, and crushing to 20-100 meshes; wherein the auxiliary materials are selected from one or more of the following components: heavy calcium carbonate, dolomite, talc, magnesite, cullet and waste glass fiber;

2) sending the product obtained in the step 1) into a Raymond mill, carrying out dry grinding, and then air-selecting particles with the particle size of less than 200 meshes to obtain powder;

3) putting the powder obtained in the step 2) and 15-35 parts by weight of pore-forming agent into a mixer, mixing the materials by a dry method, and humidifying the materials until the water content is 4-10% (specifically taking the use of a press as a standard) to obtain a formula material;

4) conveying the formula material obtained in the step 3) to an automatic press to be pressed into a semi-finished product with the thickness of 10-50 mm;

5) and (4) firing the semi-finished product in the step 4).

Preferably, the raw material comprises 30-70% of fly ash, 15-50% of feldspar, 2-8% of auxiliary material and 15-35% of pore-forming agent by mass.

Preferably, the pore former is selected from one or several of the following components: coal slime, municipal sludge and river sludge.

Preferably, the material mixing process in the step 3) comprises the following steps: adding 15-35 parts by weight of pore-forming agent into a mixer, spraying water to moisten the surface of the pore-forming agent, adding the powder obtained in the step 2), mixing, and coating the surface of the pore-forming agent with the powder with the thickness of 0.2-1.0 mm.

Preferably, the water content in step 3) is 6%.

Preferably, the firing in step 5) is performed in a roller kiln or a tunnel kiln.

Preferably, the sintering temperature in the step 5) is 800-1000 ℃, and the sintering time is 1-10 hours.

Preferably, the method further comprises the following step 6): and 5) cooling the sintered product, and crushing or cutting the product into a required shape to obtain a finished product.

Preferably, the pore former is required to form similar particles in terms of the porosity and pore size required for the expanded vermiculite.

Preferably, the amount of heat generated by the pore-forming agent is less than the energy consumption required for the firing temperature.

Preferably, the shape of the pore former is: flaky particles with the average diameter of 2-3 mm.

The invention provides a method for preparing artificial expanded vermiculite by using fly ash. The method takes fly ash as a main material, and feldspar like raw materials, auxiliary materials and pore-forming agents are added, so that the technical requirements of the process for producing the artificial expanded vermiculite by the fly ash are met through a dry-method powder-making processing process.

The invention produces a natural vermiculite substitute product by utilizing tailings and industrial solid wastes in an artificial synthesis mode, solves the storage problem of feldspar-like tailings and industrial solid wastes, and also solves the problem of vermiculite shortage of mines caused by sealing mountains, cultivating forests and resource exhaustion.

The invention ensures the porosity, water absorption, activity and strength of the artificial expanded vermiculite by a special processing technology, a reasonable formula and a firing method.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described in detail. Well-known structures or functions may not be described in detail in the following embodiments in order to avoid unnecessarily obscuring the details. Approximating language, as used herein in the following examples, may be applied to identify quantitative representations that could permissibly vary in number without resulting in a change in the basic function. Unless defined otherwise, technical and scientific terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The overall technical scheme of the invention is as follows:

(1) ingredients

The raw materials comprise 30-70% of fly ash, 15-50% of feldspar like raw material, 2-8% of auxiliary material and 15-35% of pore-forming agent by mass percent; as the fly ash is a relatively fine material, the fly ash becomes lighter and finer to grind under the same condition, so that the minerals of the feldspar like raw materials need to be crushed, and the fly ash, the feldspar like raw materials and the auxiliary materials are crushed to 20-100 meshes, so that the particle size matching of the materials is reasonable, and the grinding efficiency and the uniformity and the dispersibility of the materials are improved.

(2) Grinding

And mixing the crushed fly ash and the feldspar-like raw material with auxiliary materials, putting the mixture into a continuous Raymond mill, carrying out dry grinding, and then air-selecting particles with the particle size of less than 200 meshes to obtain powder.

(3) Granulation of pore-forming agent

Processing the pore-forming agent into flaky particles with the average diameter of 2-3 mm.

(4) Mixing material

Humidifying the powder material obtained in the step (2) to the moisture content of about 6% and then adding the pore-forming agent obtained in the step (3) to mix uniformly, so that the surface of the pore-forming agent is uniformly coated with a layer of the powder material obtained in the step (2), and obtaining the formula material.

(5) Profiling die

Pressing the humidified formula material obtained in the step (4) into a board with the thickness of 10-50 mm by using a press.

(6) Firing into

And (5) drying the board obtained in the step (5), and then feeding the dried board into a kiln for sintering.

(7) Crushing

And cooling the sintered plate, and crushing or cutting the plate into a required shape to obtain a finished product.

Preferably, the feldspar-like raw material is one or more of feldspar, tailings with similar components to the feldspar or industrial solid waste.

Preferably, the auxiliary materials are one or more of heavy calcium carbonate, dolomite, talc, magnesite, cullet and waste glass fiber.

Preferably, the pore-forming agent is one or more of coal slime, municipal sludge and river sludge or waste materials with large loss on ignition.

Preferably, the pore former needs to be processed into a desired shape, and the particle size is determined according to the pore size.

Preferably, the dry grinding in step (2) is carried out by air separation to separate particles with a particle size of less than 200 meshes. The powder meeting the requirement of the particle size in the grinding process by adopting the winnowing process can be immediately selected, and the over-grinding phenomenon in the grinding process is avoided as much as possible, so that the energy consumption required by grinding is greatly reduced.

Preferably, after the materials are mixed in the step (3), the surface of the pore-forming agent is uniformly coated with a layer of powder, and the thickness of the powder is 0.2-1.0 mm.

Preferably, the amount of heat generated by the pore-forming agent must be less than the energy consumption required for the firing temperature.

Preferably, the sintering temperature in the step (4) is 800-.

Example 1

The production process of artificial expanded vermiculite with flyash includes the following steps:

(1) coarse crushing of the ingredients

The raw materials comprise 60% of fly ash, 5% of feldspar-like raw material, 5% of auxiliary material and 30% of pore-forming agent by mass, the fly ash, the feldspar-like raw material and the auxiliary material are coarsely crushed to 20-100 meshes, and the fly ash, the feldspar-like raw material and the auxiliary material are coarsely crushed to below 30 meshes;

(2) grinding

Mixing the coarsely crushed fly ash and feldspar-like raw materials with auxiliary materials, putting the mixture into a Raymond mill, carrying out dry grinding, and then air-selecting fine powder with the particle size of below 200 meshes to obtain the fineness of the powder: 200-mesh sieve residue of feldspar like 1.5%, 200-mesh sieve residue of fly ash 1.5%, and 200-mesh sieve residue 0.8% of auxiliary materials to obtain powder.

(3) Granulation of pore-forming agent

The pore-forming agent is processed into flaky particles with the diameter of less than 10mm and the thickness of about 2 mm.

(4) Mixing material

And (3) putting the pore-forming agent obtained in the step (3) into a mixer in proportion, adding 2% of water, mixing for 30 seconds by a dry method, adding the powder obtained in the step (2), continuously adding 3% of water, and coating the surface of the pore-forming agent with about 2mm of powder to obtain the formula material.

(5) Profiling die

Pressing the formula material obtained in the step (4) into 100 x 200 x 10mm cubes by using a 100 ton press.

(6) Firing into

And (4) putting the square blocks obtained in the step (5) into a roller kiln, and then sintering at the sintering temperature of 1000 ℃ for 1 hour. (ii) a

The auxiliary materials are talc and dolomite, and the feldspar-like raw material is gold ore flotation tailings.

The pore-forming agent is municipal sludge and lignocellulose.

The firing kiln is a roller kiln.

Example 2

(1) coarse crushing of the ingredients

The raw materials comprise 50% of fly ash, 15% of feldspar like raw material, 9% of auxiliary material and 26% of pore-forming agent by mass, and the fly ash, the feldspar like raw material and the auxiliary material are coarsely crushed to 40 meshes.

(2) Grinding

Mixing the coarsely crushed fly ash and feldspar raw materials with auxiliary materials, putting the mixture into a Raymond mill, carrying out dry grinding, and then carrying out air separation on fine powder with the particle size of below 200 meshes to obtain the powder with the fineness of 0.5 percent of feldspar-like 200 meshes, 1.4 percent of fly ash 200 meshes and 0.8 percent of auxiliary materials 200 meshes, thus obtaining the powder.

3) Granulation of pore-forming agent

(4) Mixing material

And (3) putting the pore-forming agent obtained in the step (3) into a mixer in proportion, adding 2% of water, mixing for 30 seconds by a dry method, adding the powder obtained in the step (2), continuously adding 5% of water, and coating the surface of the pore-forming agent with about 3mm of powder to obtain the formula material.

(5) Profiling die

Pressing the formula material obtained in the step (4) into 100 x 200 x 25mm cubes by using a 100 ton press.

(6) Firing into

And (4) putting the square block obtained in the step (5) into a roller kiln, and then sintering at 880 ℃ for 3 hours.

The auxiliary materials are heavy calcium carbonate and dolomite, and the feldspar-like raw material is gold ore flotation tailings.

The pore-forming agent is municipal sludge and lignocellulose.

The kiln is a roller kiln.

Example 3

(1) coarse crushing of the ingredients

The raw materials comprise 30% of fly ash, 50% of feldspar, 5% of auxiliary material and 15% of municipal sludge in percentage by mass, and the fly ash, the feldspar and the auxiliary material are coarsely crushed to 80 meshes.

(2) Grinding

Mixing the coarsely crushed fly ash and feldspar raw materials with auxiliary materials, putting the mixture into a Raymond mill, carrying out dry grinding, and then carrying out air separation on fine powder with the particle size of below 200 meshes to obtain the powder with the fineness of 1.5 percent of feldspar-like 200 meshes, 1 percent of fly ash 200 meshes and 0.8 percent of auxiliary materials 200 meshes to obtain the powder.

3) Granulation of pore-forming agent

(4) Mixing material

(5) Profiling die

Pressing the formula material obtained in the step (4) into 100 x 200 x 50mm cubes by using a 100 ton press.

(6) Firing into

And (4) putting the square block obtained in the step (5) into a kiln, and then sintering at the sintering temperature of 1000 ℃ for 10 hours.

The auxiliary materials are heavy calcium carbonate and talc, and the feldspar-like raw material is gold ore flotation tailings.

The pore-forming agent is municipal sludge.

The kiln is a tunnel kiln.

Example 4

(1) coarse crushing of the ingredients

(2) Grinding

(3) Mixing material

And (3) mixing the powder obtained in the step (2) with a pore-forming agent in proportion, and adding 5% of water to obtain the formula material.

(4) Profiling die

Pressing the formula material obtained in the step (3) into 100 x 200 x 25mm cubes by using a 100 ton press.

(5) Firing into

And (4) putting the square blocks obtained in the step (4) into a roller kiln, and then sintering at 880 ℃ for 3 hours.

The pore-forming agent is municipal sludge and lignocellulose.

The pore former is not granulated.

The kiln is a roller kiln.

Example 5

(1) coarse crushing of the ingredients

(2) Grinding

3) Granulation of pore-forming agent

(4) Mixing material

And (3) putting the powder obtained in the step (2) and the pore-forming agent obtained in the step (3) into a mixer in proportion, adding 5% of water, and mixing for 60 seconds by a dry method to obtain the formula material.

(5) Profiling die

(6) Firing into

The pore-forming agent is municipal sludge.

In the process, the pore-forming agent and the powder are not coated.

The kiln is a tunnel kiln.

The artificial expanded vermiculite samples prepared in examples 1-5 were tested for properties and the test data are shown in table 1.

TABLE 1 indices for samples of examples 1-5

As can be seen from the test results in Table 1, examples 1-3 can reach the national standard for expanded vermiculite; examples 4-5 samples did not meet the national standards because the pore former was not granulated, or did not form a coating with the powder after granulation.

The embodiments of the present invention have been described in detail, but the description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention. Any modification, equivalent replacement, and improvement made within the scope of the application of the present invention should be included in the protection scope of the present invention.

Claims

1. The method for preparing the artificial expanded vermiculite by using the fly ash is characterized by comprising the following steps of:

3) putting the powder obtained in the step 2) and 15-35 parts by weight of pore-forming agent into a mixer, mixing by a dry method, and humidifying until the water content is 4% -10% to obtain a formula material;

5) and (4) firing the semi-finished product in the step 4).

2. The method for preparing the artificial expanded vermiculite by using the fly ash as claimed in claim 1, wherein the raw material comprises 30-70% of the fly ash, 15-50% of the feldspar, 2-8% of the auxiliary material and 15-35% of the pore-forming agent by mass.

3. The method for preparing artificial expanded vermiculite from fly ash according to claim 1, wherein the pore former is selected from one or several of the following components: coal slime, municipal sludge and river sludge.

4. The method for preparing artificial expanded vermiculite by using fly ash as claimed in claim 1, wherein the mixing process in step 3) is as follows: adding 15-35 parts by weight of pore-forming agent into a mixer, spraying water to moisten the surface of the pore-forming agent, adding the powder obtained in the step 2), mixing, and coating the surface of the pore-forming agent with the powder with the thickness of 0.2-1.0 mm.

5. The method for preparing artificial expanded vermiculite from fly ash according to claim 1, wherein the water content in step 3) is 6%.

6. The method for preparing artificial expanded vermiculite from fly ash as claimed in claim 1, wherein the firing in step 5) is performed in a roller kiln or a tunnel kiln.

7. The method for preparing the artificial expanded vermiculite by using the fly ash as claimed in claim 1, wherein the firing temperature in the step 5) is 800-1000 ℃, and the firing time is 1-10 hours.

8. The method for preparing artificial expanded vermiculite from fly ash according to claim 1, further comprising the following step 6): and 5) cooling the sintered product, and crushing or cutting the product into a required shape to obtain a finished product.