CN112125698B - Medium-density diatomite fiber cement board and preparation method thereof - Google Patents

Abstract

The invention provides a medium-density diatomite fiber cement board which comprises the following components in parts by weight: 22-30 parts of diatomite, 20-30 parts of quartz sand, 35-48 parts of cement, 0-10 parts of fly ash, 2-8 parts of silica fume, 1-5 parts of lignocellulose and 0.5-1 part of hydroxypropyl methyl cellulose. In addition, the invention also provides a preparation method of the medium-density diatomite fiber cement board. According to the invention, the diatomite is used for partially replacing quartz stone, the bulk density and hardness of the diatomite are far lower than those of quartz sand, and compared with a high-density fiber cement board prepared by taking pure quartz sand as a raw material, the board prepared by the diatomite has lighter self weight, less accessories and keels required by board building construction, low cost and high construction efficiency, and the product competitiveness of the board is improved; meanwhile, the vacuum extrusion process is adopted for production, the water consumption is less than that of the traditional pulp flowing method and the traditional paper making method, and the produced plate has the excellent characteristics of low porosity, high breaking strength, good durability and the like.

Description

Medium-density diatomite fiber cement board and preparation method thereof

Technical Field

The invention belongs to the technical field of building materials, and particularly relates to a medium-density diatomite fiber cement board and a preparation method thereof.

Background

The fiber cement board is one of the artificial boards, has a plurality of excellent functions, such as high strength, weather resistance, moisture resistance, water resistance, flame retardance, mildew resistance, bacteria resistance, good machining (sawing, drilling, nailing, punching, slotting and the like) performance, easy decoration and good sound insulation, heat insulation and the like, and is applied to the fields of non-bearing inner and outer wallboards, ceilings, composite wallboards and the like as a series of advantages as a novel building material along with the rapid development of national economy and the acceleration of urbanization process according to the national policy requirements of energy conservation, emission reduction and environmental protection. Diatomite is a natural mineral material with biological origin, and the chemical component is mainly SiO₂The bulk density is 0.34 to 0.65g/cm³A specific surface area of 40 to 65m²The diatomite has strong activity and adsorption, wide application due to special physical and chemical properties, and wide application rangeThe medium-density diatomite fiber cement board prepared from the fiber cement board has excellent performance and meets the market demand.

In recent years, medium-density diatomite fiber cement boards on the market are usually formed by adopting a pulp flowing method or a sheet-making method and then are subjected to autoclaved curing or steam curing. For example, chinese patent CN104446298A discloses a method for preparing a diatomite fiber cement board, which comprises mixing raw materials with water uniformly, and using a slurry flow process to obtain a board with low strength; chinese patent CN103880349A discloses a method for preparing diatomite fiber cement board, which comprises mixing raw materials with water for pulping, and adopting a pulp flow process to obtain the board with low breaking strength, large porosity and poor durability.

Disclosure of Invention

The invention aims to solve the problems that the conventional diatomite fiber cement board is low in breaking strength, large in porosity and poor in board durability.

Therefore, the invention provides a medium-density diatomite fiber cement board which comprises the following components in parts by weight: 22-30 parts of diatomite, 20-30 parts of quartz sand, 35-48 parts of cement, 0-10 parts of fly ash, 2-8 parts of silica fume, 1-5 parts of lignocellulose and 0.5-1 part of hydroxypropyl methyl cellulose.

Further, SiO in the diatomite₂The content of the diatomite is more than 70wt percent, and the balance of the diatomite 200-mesh sieve is less than 1wt percent.

Further, SiO in the quartz sand₂The content of the quartz sand is more than 90wt%, and the balance of the quartz sand with a 200-mesh sieve is less than 1 wt%.

Further, the cement is ordinary portland cement.

Further, SiO in the fly ash₂Content of > 50wt%, Al₂O₃The content of the fly ash is more than 27wt percent, and the balance of the fly ash is less than 5 percent after being sieved by a 200-mesh sieve.

Further, SiO in the micro silicon powder₂The content of the silicon micro-powder is more than 90wt%, and the balance of the silicon micro-powder with 500 meshes is less than 1 wt%.

Further, the length of the lignocellulose is 0.2-2 mm.

Further, the density of the medium-density diatomite fiber cement board is 1.30-1.36 g/cm³And the breaking strength is 16.8-19.6 MPa.

In addition, the invention also provides a preparation method of the medium-density diatomite fiber cement board, which comprises the following steps:

1) weighing diatomite, quartz sand, cement, fly ash, silica fume, lignocellulose and hydroxypropyl methyl cellulose according to the designed dosage, putting the weighed materials into a high-speed mixer, uniformly mixing, pouring the mixed powder and water into a kneading machine, and uniformly kneading to obtain pug with the water content of 30-40 wt%;

2) putting the pug obtained in the step 1) into an extruder for extrusion molding to obtain a wet blank;

3) placing the wet blank prepared in the step 2) into a pre-curing box, and curing for 4-8 hours by using moisture at the temperature of 20-22 ℃ to obtain a blank;

4) placing the blank obtained in the step 3) into an autoclave, and maintaining for 8-12 h under the saturated vapor pressure of 0.9-1.1 MPa at constant pressure to obtain a medium-density diatomite fiber cement board sample;

5) and 4) drying the medium-density diatomite fiber cement board sample obtained in the step 4) to enable the water content of the medium-density diatomite fiber cement board sample to be lower than 10wt%, so as to obtain the medium-density diatomite fiber cement board.

Further, the technical conditions of the pug extrusion molding in the step 2) are as follows: the pugging shaft frequency of the extruder is 20-30 HZ, the extrusion shaft frequency is 20-30 HZ, and the extrusion vacuum degree of the vacuum extruder is-0.08-0.95 MPa.

Compared with the prior art, the invention has the beneficial effects that:

(1) the middle-density diatomite fiber cement board provided by the invention adopts diatomite to partially replace quartz stone, the stacking density and hardness of the diatomite are far lower than those of quartz sand, compared with a high-density fiber cement board prepared by taking pure quartz sand as a raw material, the board prepared by the diatomite has lighter dead weight, the board is easier to cut during building construction, fewer accessories required by engineering construction are needed, the use specification of a structural keel is smaller, an installation structure without a cross keel can be adopted, the structure is simple, the material cost is low, the construction efficiency is high, and the purpose of reducing the weight of a building is achieved while the whole engineering cost is reduced.

(2) The medium-density diatomite fiber cement board provided by the invention is produced by adopting a vacuum extrusion process in the preparation process, the process does not generate three wastes, the cost of treating the three wastes by enterprises is saved while the environmental pollution is reduced, the requirements of national advocated green environmental protection policy are met, the product types are more abundant and various by changing the structure of an extrusion die, and the requirements of the market on various types of boards are met; compared with the traditional pulp flowing method and paper making method, the water consumption is less, and the produced sheet material has the excellent characteristics of low porosity, high breaking strength, good durability and the like.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

the embodiment provides a medium-density diatomite fiber cement board which comprises the following components in parts by weight: 30 parts of diatomite, 22 parts of quartz sand, 43 parts of cement, 7 parts of fly ash, 5 parts of silica fume, 3 parts of lignin fiber and 1 part of hydroxypropyl methyl cellulose. Wherein, SiO in diatomite₂The content of the diatomite is more than 70 wt%, and the balance of the diatomite 200-mesh sieve is less than 1 wt%; SiO in quartz sand₂The content of the quartz sand is more than 90wt%, and the balance of the quartz sand with a 200-mesh sieve is less than 1 wt%; the cement is ordinary portland cement; SiO in fly ash₂Content of > 50wt%, Al₂O₃The content of the fly ash is more than 27wt percent, and the balance of the fly ash is less than 5 percent after being sieved by a 200-mesh sieve; SiO in micro silicon powder₂The content of the silicon micro-powder is more than 90wt%, and the balance of the silicon micro-powder with 500 meshes is less than 1 wt%; the length of the lignin fiber is 0.2-2 mm.

The specific preparation process of the medium-density diatomite fiber cement board is as follows:

(1) weighing the diatomite, the quartz sand, the cement, the fly ash, the micro silicon powder, the lignin fiber and the hydroxypropyl methyl cellulose according to the above dosage ratio, putting the weighed materials into a high-speed mixer, uniformly mixing, pouring the mixed powder and water into a kneader, and uniformly kneading to obtain a pug with the water content of 30-40 wt%.

(2) Putting the pug obtained in the step 1) into an extruder, wherein the frequency of a pugging shaft of the extruder is 20-30 HZ, the frequency of an extrusion shaft is 20-30 HZ, the extrusion vacuum degree of the vacuum extruder is-0.08 to-0.95 MPa, and extruding and forming to obtain a wet blank;

(3) and (3) placing the wet blank prepared in the step (2) into a pre-curing box, and curing for 6 hours by using moisture at the temperature of 20 ℃ to obtain a blank.

(4) And (4) placing the blank obtained in the step (3) into a still kettle, and maintaining for 10 hours under the saturated vapor pressure of 1.0MPa at constant pressure to obtain a medium-density diatomite fiber cement board sample.

(5) And (5) drying the medium-density diatomite fiber cement board sample obtained in the step (4) through an oven to enable the water content of the medium-density diatomite fiber cement board sample to be lower than 10wt%, and thus obtaining the medium-density diatomite fiber cement board.

Example 2:

the embodiment provides a medium-density diatomite fiber cement board which comprises the following components in parts by weight: 25 parts of diatomite, 27 parts of quartz sand, 43 parts of cement, 7 parts of fly ash, 5 parts of silica fume, 3 parts of lignin fiber and 1 part of hydroxypropyl methyl cellulose. Wherein, SiO in diatomite₂The content of the diatomite is more than 70 wt%, and the balance of the diatomite 200-mesh sieve is less than 1 wt%; SiO in quartz sand₂The content of the quartz sand is more than 90wt%, and the balance of the quartz sand with a 200-mesh sieve is less than 1 wt%; the cement is ordinary portland cement; SiO in fly ash₂Content of > 50wt%, Al₂O₃The content of the fly ash is more than 27wt percent, and the balance of the fly ash is less than 5 percent after being sieved by a 200-mesh sieve; SiO in micro silicon powder₂The content of the silicon micro-powder is more than 90wt%, and the balance of the silicon micro-powder with 500 meshes is less than 1 wt%; the length of the lignin fiber is 0.2-2 mm.

The specific preparation process of the medium-density diatomite fiber cement board is as follows:

(1) weighing the diatomite, the quartz sand, the cement, the fly ash, the micro silicon powder, the lignin fiber and the hydroxypropyl methyl cellulose according to the above dosage ratio, putting the weighed materials into a high-speed mixer, uniformly mixing, pouring the mixed powder and water into a kneader, and uniformly kneading to obtain a pug with the water content of 30-40 wt%.

(2) Putting the pug obtained in the step 1) into an extruder, wherein the frequency of a pugging shaft of the extruder is 20-30 HZ, the frequency of an extrusion shaft is 20-30 HZ, the extrusion vacuum degree of the vacuum extruder is-0.08 to-0.95 MPa, and extruding and forming to obtain a wet blank;

(3) and (3) placing the wet blank prepared in the step (2) into a pre-curing box, and curing for 6 hours by using moisture at the temperature of 20 ℃ to obtain a blank.

(4) And (4) placing the blank obtained in the step (3) into a still kettle, and maintaining for 10 hours under the saturated vapor pressure of 1.0MPa at constant pressure to obtain a medium-density diatomite fiber cement board sample.

(5) And (5) drying the medium-density diatomite fiber cement board sample obtained in the step (4) through an oven to enable the water content of the medium-density diatomite fiber cement board sample to be lower than 10wt%, and thus obtaining the medium-density diatomite fiber cement board.

Example 3:

the embodiment provides a medium-density diatomite fiber cement board which comprises the following components in parts by weight: 22 parts of diatomite, 30 parts of quartz sand, 43 parts of cement, 7 parts of fly ash, 5 parts of silica fume, 3 parts of lignin fiber and 1 part of hydroxypropyl methyl cellulose. Wherein, SiO in diatomite₂The content of the diatomite is more than 70 wt%, and the balance of the diatomite 200-mesh sieve is less than 1 wt%; SiO in quartz sand₂The content of the quartz sand is more than 90wt%, and the balance of the quartz sand with a 200-mesh sieve is less than 1 wt%; the cement is ordinary portland cement; SiO in fly ash₂Content of > 50wt%, Al₂O₃The content of the fly ash is more than 27wt percent, and the balance of the fly ash is less than 5 percent after being sieved by a 200-mesh sieve; SiO in micro silicon powder₂The content of the silicon micro-powder is more than 90wt%, and the balance of the silicon micro-powder with 500 meshes is less than 1 wt%; the length of the lignin fiber is 0.2-2 mm.

The specific preparation process of the medium-density diatomite fiber cement board is as follows:

(1) weighing the diatomite, the quartz sand, the cement, the fly ash, the micro silicon powder, the lignin fiber and the hydroxypropyl methyl cellulose according to the above dosage ratio, putting the weighed materials into a high-speed mixer, uniformly mixing, pouring the mixed powder and water into a kneader, and uniformly kneading to obtain a pug with the water content of 30-40 wt%.

(2) Putting the pug obtained in the step 1) into an extruder, wherein the frequency of a pugging shaft of the extruder is 20-30 HZ, the frequency of an extrusion shaft is 20-30 HZ, the extrusion vacuum degree of the vacuum extruder is-0.08 to-0.95 MPa, and extruding and forming to obtain a wet blank;

(3) and (3) placing the wet blank prepared in the step (2) into a pre-curing box, and curing for 6 hours by using moisture at the temperature of 20 ℃ to obtain a blank.

(4) And (4) placing the blank obtained in the step (3) into a still kettle, and maintaining for 10 hours under the saturated vapor pressure of 1.0MPa at constant pressure to obtain a medium-density diatomite fiber cement board sample.

(5) And (5) drying the medium-density diatomite fiber cement board sample obtained in the step (4) through an oven to enable the water content of the medium-density diatomite fiber cement board sample to be lower than 10wt%, and thus obtaining the medium-density diatomite fiber cement board.

Example 4:

the embodiment provides a medium-density diatomite fiber cement board which comprises the following components in parts by weight: 25 parts of diatomite, 20 parts of quartz sand, 35 parts of cement, 10 parts of fly ash, 8 parts of silica fume, 5 parts of lignin fiber and 0.5 part of hydroxypropyl methyl cellulose. Wherein, SiO in diatomite₂The content of the diatomite is more than 70 wt%, and the balance of the diatomite 200-mesh sieve is less than 1 wt%; SiO in quartz sand₂The content of the quartz sand is more than 90wt%, and the balance of the quartz sand with a 200-mesh sieve is less than 1 wt%; the cement is ordinary portland cement; SiO in fly ash₂Content of > 50wt%, Al₂O₃The content of the fly ash is more than 27wt percent, and the balance of the fly ash is less than 5 percent after being sieved by a 200-mesh sieve; SiO in micro silicon powder₂The content of the silicon micro-powder is more than 90wt%, and the balance of the silicon micro-powder with 500 meshes is less than 1 wt%; the length of the lignin fiber is 0.2-2 mm.

The specific preparation process of the medium-density diatomite fiber cement board is as follows:

(1) weighing the diatomite, the quartz sand, the cement, the fly ash, the micro silicon powder, the lignin fiber and the hydroxypropyl methyl cellulose according to the above dosage ratio, putting the weighed materials into a high-speed mixer, uniformly mixing, pouring the mixed powder and water into a kneader, and uniformly kneading to obtain a pug with the water content of 30-40 wt%.

(2) Putting the pug obtained in the step 1) into an extruder, wherein the frequency of a pugging shaft of the extruder is 20-30 HZ, the frequency of an extrusion shaft is 20-30 HZ, the extrusion vacuum degree of the vacuum extruder is-0.08 to-0.95 MPa, and extruding and forming to obtain a wet blank;

(3) and (3) placing the wet blank prepared in the step (2) into a pre-curing box, and curing for 6 hours by using moisture at the temperature of 20 ℃ to obtain a blank.

(4) And (4) placing the blank obtained in the step (3) into a still kettle, and maintaining for 10 hours under the saturated vapor pressure of 1.0MPa at constant pressure to obtain a medium-density diatomite fiber cement board sample.

(5) And (5) drying the medium-density diatomite fiber cement board sample obtained in the step (4) through an oven to enable the water content of the medium-density diatomite fiber cement board sample to be lower than 10wt%, and thus obtaining the medium-density diatomite fiber cement board.

Example 5:

the embodiment provides a medium-density diatomite fiber cement board which comprises the following components in parts by weight: 29 parts of diatomite, 23 parts of quartz sand, 48 parts of cement, 2 parts of silica fume, 1 part of lignin fiber and 0.8 part of hydroxypropyl methyl cellulose. Wherein, SiO in diatomite₂The content of the diatomite is more than 70 wt%, and the balance of the diatomite 200-mesh sieve is less than 1 wt%; SiO in quartz sand₂The content of the quartz sand is more than 90wt%, and the balance of the quartz sand with a 200-mesh sieve is less than 1 wt%; the cement is ordinary portland cement; SiO in micro silicon powder₂The content of the silicon micro-powder is more than 90wt%, and the balance of the silicon micro-powder with 500 meshes is less than 1 wt%; the length of the lignin fiber is 0.2-2 mm.

The specific preparation process of the medium-density diatomite fiber cement board is as follows:

(1) weighing the diatomite, the quartz sand, the cement, the silica fume, the lignin fiber and the hydroxypropyl methyl cellulose according to the above dosage ratio, putting the weighed materials into a high-speed mixer for uniform mixing, and pouring the mixed powder and water into a kneader for uniform kneading to obtain the pug with the water content of 30-40 wt%.

(2) Putting the pug obtained in the step 1) into an extruder, wherein the frequency of a pugging shaft of the extruder is 20-30 HZ, the frequency of an extrusion shaft is 20-30 HZ, the extrusion vacuum degree of the vacuum extruder is-0.08 to-0.95 MPa, and extruding and forming to obtain a wet blank;

(3) and (3) placing the wet blank prepared in the step (2) into a pre-curing box, and curing for 6 hours by using moisture at the temperature of 20 ℃ to obtain a blank.

(4) And (4) placing the blank obtained in the step (3) into a still kettle, and maintaining for 10 hours under the saturated vapor pressure of 1.0MPa at constant pressure to obtain a medium-density diatomite fiber cement board sample.

(5) And (5) drying the medium-density diatomite fiber cement board sample obtained in the step (4) through an oven to enable the water content of the medium-density diatomite fiber cement board sample to be lower than 10wt%, and thus obtaining the medium-density diatomite fiber cement board.

Comparative example:

the middle-density diatomite fiber cement board prepared by adopting a pulp flowing process comprises the following components in parts by weight: 30 parts of diatomite, 22 parts of quartz sand, 43 parts of cement, 7 parts of fly ash, 5 parts of silica fume and 3 parts of lignin fiber, wherein the specific preparation process of the medium-density diatomite fiber cement board in the comparative example is as follows:

(1) the diatomite raw ore is naturally dried, weathered, crushed and ground to ensure that the granularity reaches more than 200 meshes.

(2) Uniformly mixing the diatomite treated in the step (1) with lignin fibers, quartz sand, cement, micro silicon powder and fly ash, adding water for pulping to obtain slurry with the mass concentration of 14-21%, and preparing a wet blank of the medium-density diatomite fiber cement board by a slurry flowing process.

(3) And (3) placing the medium-density diatomite fiber cement board wet blank prepared in the step (2) into a pre-curing box, and curing for 6 hours by moisture under the condition that the temperature is 20 ℃.

(4) And (4) placing the medium-density diatomite fiber cement board prepared in the step (3) into a still kettle, performing constant-pressure maintenance for 10 hours after the saturated vapor pressure of 1.0MPa is reached through a 4-hour pressure increasing process, and performing a 3-hour pressure reducing process to finally prepare a sample of the medium-density diatomite fiber cement board.

(5) And (5) drying the medium-density diatomite fiber cement board prepared in the step (4) by using a dryer to enable the moisture content of the medium-density diatomite fiber cement board to be lower than 10wt%, and finally obtaining the medium-density diatomite fiber cement board.

The physical properties of the medium density diatomite fiber cement boards prepared in the above examples 1 to 5 and comparative example were measured, and the results are shown in table 1.

Table 1:

from the test results of the medium density diatomite fiber cement board in table 1, it is understood that the density of the medium density diatomite fiber cement board is decreased and the porosity is increased with the increase of the added amount of diatomite, and the breaking strength ratio and the breaking strength are slightly decreased after 100 cycles of freeze-thaw. Compared with the medium-density diatomite fiber cement board produced by the pulp flow process, the medium-density diatomite fiber cement board produced by the vacuum extrusion process has lower porosity and higher breaking strength under the same density (namely example 1 and a comparative example), and meanwhile, the durability of the board produced by the vacuum extrusion process is better and meets the requirements of JC/T412.1-2018 fiber cement flat boards according to the results of the frost resistance test. Therefore, the lightweight characteristic of the medium-density diatomite fiber cement board mainly depends on the special porous structure of the diatomite, the strong surface activity capability of the diatomite is the reason that the medium-density diatomite fiber cement board can still maintain higher breaking strength under the condition of lower density, and the board produced by the vacuum extrusion process is superior to the board produced by the pulp flow method in terms of mechanical strength and durability.

The above examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention, which is intended to be covered by the claims and any design similar or equivalent to the scope of the invention.

Claims (2)

1. The medium-density diatomite fiber cement board is characterized by comprising the following components in parts by weight: 22-30 parts of diatomite, 20-30 parts of quartz sand, 35-48 parts of cement, 7-10 parts of fly ash, 2-8 parts of silica fume, 1-5 parts of lignocellulose and 0.5-1 part of hydroxypropyl methyl cellulose; wherein SiO in the diatomite₂The content of the diatomite is more than 70 wt%, and the balance of the diatomite 200-mesh sieve is less than 1 wt%; SiO in the quartz sand₂The content of the quartz sand is more than 90wt%, and the balance of the quartz sand with a 200-mesh sieve is less than 1 wt%; the cement is ordinary portland cement; SiO in the fly ash₂Content of > 50wt%, Al₂O₃The content of the fly ash is more than 27wt percent, and the balance of the fly ash is less than 5 percent after being sieved by a 200-mesh sieve; SiO in the micro silicon powder₂The content of the silicon micro-powder is more than 90wt%, and the balance of the silicon micro-powder with 500 meshes is less than 1 wt%; the length of the lignocellulose is 0.2-2 mm; the medium-density diatomite fiber cement board is prepared by the following method:

1) weighing diatomite, quartz sand, cement, fly ash, silica fume, lignocellulose and hydroxypropyl methyl cellulose according to the designed dosage, putting the weighed materials into a high-speed mixer, uniformly mixing, pouring the mixed powder and water into a kneading machine, and uniformly kneading to obtain pug with the water content of 30-40 wt%;

2) putting the pug obtained in the step 1) into an extruder for extrusion molding to obtain a wet blank; the technical conditions of the pug extrusion molding are as follows: the pugging shaft frequency of the extruder is 20-30 Hz, the extrusion shaft frequency is 20-30 Hz, and the extrusion vacuum degree of the vacuum extruder is-0.08 MPa;

3) placing the wet blank prepared in the step 2) into a pre-curing box, and curing for 4-8 hours by using moisture at the temperature of 20-22 ℃ to obtain a blank;

4) placing the blank obtained in the step 3) into an autoclave, and maintaining for 8-12 h under the saturated vapor pressure of 0.9-1.1 MPa at constant pressure to obtain a medium-density diatomite fiber cement board sample;

5) and 4) drying the medium-density diatomite fiber cement board sample obtained in the step 4) to enable the water content of the medium-density diatomite fiber cement board sample to be lower than 10wt%, so as to obtain the medium-density diatomite fiber cement board.

2. Such as rightThe medium-density diatomite fiber cement board according to claim 1, wherein the density of the medium-density diatomite fiber cement board is 1.30-1.36 g/cm³And the breaking strength is 16.8-19.6 MPa.