Preparation method of gypsum-based mortar material

Abstract

The invention discloses a gypsum-based mortar material, which is prepared from the following ingredients in parts by weight: 30 to 60 parts of gypsum, 30 to 65 parts of aggregate, 0.1 to 0.5 part of modified cellulose ether, 2 to 5 parts of redispersible latex powder, 0.2 to 1 part of waterproof agents, 0.1 to 0.5 part of retarders and 0.2 to 0.5 part of early strength agents. The invention belongs to the technical field of gypsum-based mortar preparation, and particularly relates to a preparation method of a gypsum-based mortar material.

Description

Technical Field

[0001] The invention belongs to the technical field of gypsum-based mortar preparation, and specifically refers to a method for preparing a gypsum-based mortar material. Background Art

[0002] In the field of building materials, gypsum-based mortar has always been an important material, widely used in wall plastering, masonry and other construction links. Traditional gypsum-based mortar is relatively conventional in the selection of raw materials, usually using gypsum that has not been deeply treated, which has limited purity and many impurities. This not only affects the hydration reaction efficiency of gypsum, but also leads to a significant reduction in the strength and stability of the final mortar product. In terms of aggregates, they mostly rely on a single natural aggregate, such as ordinary quartz sand, and lack an optimized combination design for aggregate performance, making it impossible to achieve multifunctional requirements such as light weight and thermal insulation while ensuring strength.

[0003] In terms of the use of additives, traditional gypsum-based mortars often simply add single cellulose ethers, latex powders, etc., with relatively simple functions, and it is difficult to meet the stringent requirements of modern construction on the various performance aspects of mortar. Summary of the invention

[0004] The technical problem to be solved by the present invention is that a single aggregate cannot take into account multiple properties, the additive has a single function and uneven dispersion, and the extensive preparation process leads to performance limitations.

[0005] In order to achieve the above functions, the technical solution adopted by the present invention is as follows: a gypsum-based mortar material, comprising the following components in parts by weight: 30-60 parts of gypsum, 30-65 parts of aggregate, 0.1-0.5 parts of modified cellulose ether, 2-5 parts of redispersible latex powder, 0.2-1 parts of waterproofing agent, 0.1-0.5 parts of retarder, and 0.2-0.5 parts of early strength agent.

[0006] Preferably, the gypsum is desulfurized gypsum with a purity of more than 85%.

[0007] Preferably, the aggregate is a composite aggregate of quartz sand and lightweight ceramsite, wherein the quartz sand has a particle size of 0.1-1.5 mm, accounting for 40-60% of the total aggregate, and the lightweight ceramsite has a particle size of 2-5 mm, accounting for 40-60% of the total aggregate.

[0008] Preferably, the waterproofing agent is a composite waterproofing agent of a silicone waterproofing agent and a calcium stearate waterproofing agent in a mass ratio of 2:1 to 3:1.

[0009] Preferably, the retarder is a compound retarder of sodium citrate and sodium gluconate, and the mass ratio of the two is 1:1-2:1.

[0010] Preferably, the early strength agent is a compound of calcium sulfate whiskers and calcium nitrate in a mass ratio of 2:1-4:1.

[0011] The present invention also discloses a method for preparing a gypsum-based mortar material, which is characterized by comprising the following steps:

[0012] step:

[0013] S1: Selection and treatment of gypsum: Industrial desulfurized gypsum is used, and the gypsum is dried in a rotary dryer at 120-130° C. for 1.5-2 hours. A breaking device is provided inside the dryer to break up the gypsum lumps during the drying process, thereby improving the drying efficiency and reducing the subsequent grinding energy consumption. The dried gypsum is ground with a vertical mill to a fineness of 150-180 meshes;

[0014] S2: Selection and preparation of aggregate: Aggregates are a composite system of recycled aggregates and natural sand. The recycled aggregates are obtained by crushing and screening concrete blocks and bricks from construction waste, with a particle size of 2-5 mm, accounting for 30%-40% of the total aggregates. Natural sand is medium-coarse sand with a particle size of 0.15-1.5 mm, accounting for 60%-70% of the total aggregates.

[0015] Soak the recycled aggregate in an aqueous solution containing 5%-8% cement slurry for 2-3 hours to adhere a layer of cement slurry to the surface of the recycled aggregate, then remove it and dry it in the natural environment for 1-2 days. This treatment can improve the bonding strength between the recycled aggregate and the gypsum matrix and make up for the defect of insufficient strength of the recycled aggregate itself;

[0016] S3: Preparation of additive pre-dispersion liquid: After accurately weighing the modified cellulose ether, redispersible latex powder, waterproofing agent, retarder and early strength agent according to weight, put them into an ultrasonic device, set the ultrasonic frequency to 20-30kHz, and treat for 3-5 minutes to disperse the additives preliminarily, then put them into a mixer and stir them at a high speed of 1000-1500r / min for 4-6 minutes to form an additive pre-dispersion liquid. During the stirring process, the temperature inside the equipment is controlled at 25-30°C to prevent excessive heat generated by high-speed stirring from causing changes in the performance of the additives;

[0017] S4: Mixing and stirring: Add the treated gypsum and composite aggregate into a twin-shaft forced mixer, first stir at a low speed (100-150r / min) for 2-3 minutes to make the materials initially mixed and evenly mixed, then slowly add the additive pre-dispersion liquid into the mixer, and at the same time increase the mixer speed to 250-300r / min and stir for 6-8 minutes until the material becomes a uniform mortar. During the stirring process, spray a small amount of water mist into the mixer through a spray device (the amount of water mist is 1%-2% of the total weight of the mortar) to replenish the water loss caused by stirring and ensure the working performance of the mortar.

[0018] The present invention adopts the above structure to achieve the following beneficial effects: first, raw materials are optimized, high-purity desulfurized gypsum is matched with recycled-natural sand composite aggregate, which not only improves performance but also reduces cost and enhances bonding; second, additives and processes are coordinated, and the composite additives are subjected to ultrasonic-temperature control treatment and combined with a precise mixing process, so that the mortar has multiple excellent properties such as waterproofing, slow setting, early strength, etc., and has high stability and strong adaptability. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Embodiment 1:

[0021] S1: Raw material preparation, select 45 parts of industrial desulfurization gypsum with a purity of 86%, dry the gypsum in a rotary dryer at 125°C for 1.8 hours, and the breaking device in the dryer effectively breaks up the agglomerated gypsum. Use a vertical mill to grind the dried gypsum to a fineness of 160 mesh;

[0022] Aggregates are made of recycled aggregates and natural sand, with a total of 55 parts, of which recycled aggregates come from concrete blocks and bricks in construction waste, with a particle size of 2-5 mm, and 19.25 parts (accounting for 35% of the total aggregate) are taken. The recycled aggregates are soaked in an aqueous solution containing 6% cement slurry for 2.5 hours, and then dried in a natural environment for 1.5 days. Natural sand is medium-coarse sand with a particle size of 0.15-1.5 mm, and 35.75 parts (accounting for 65% of the total aggregate) are taken.

[0023] Accurately weigh 0.3 parts of modified cellulose ether, 3.5 parts of redispersible latex powder, 0.6 parts of waterproofing agent (compounded by silicone waterproofing agent and calcium stearate waterproofing agent in a mass ratio of 2.5:1), 0.3 parts of retarder (compounded by sodium citrate and sodium gluconate in a mass ratio of 1.5:1), and 0.35 parts of early strength agent (compounded by calcium sulfate whisker and calcium nitrate in a mass ratio of 3:1);

[0024] S2: Preparation of additive pre-dispersion liquid: the weighed additive is placed in an ultrasonic device with an ultrasonic frequency set to 25 kHz for 4 minutes to make the additive preliminarily dispersed, and then placed in a stirrer and stirred at a high speed of 1200 r / min for 5 minutes to form an additive pre-dispersion liquid. During the stirring process, the internal temperature of the equipment is controlled at 28°C;

[0025] S3: Mixing and stirring. Add the treated gypsum and composite aggregate into a twin-shaft forced mixer. First, stir at a low speed of 120 r / min for 2.5 minutes. Then slowly add the additive pre-dispersion liquid. At the same time, increase the mixer speed to 280 r / min and stir for 7 minutes. During the stirring process, spray a small amount of water mist into the mixer through a spray device (the amount of water mist is 1.5% of the total weight of the mortar) to obtain a uniform mortar-like material.

[0026] Embodiment 2:

[0027] S1: Raw material preparation, 50 parts of industrial desulfurized gypsum with a purity of 88%, dried in a rotary dryer at 128°C for 1.6 hours, and ground into 170 meshes by a vertical mill;

[0028] A total of 50 parts of recycled aggregate and natural sand were compounded. The particle size of recycled aggregate was 2-5mm, and 16 parts (accounting for 32% of the total aggregate) were taken. They were soaked in cement slurry (7% concentration) for 2.2 hours and then dried for 1.8 days. The particle size of natural sand was 0.15-1.5mm, and 34 parts (accounting for 68% of the total aggregate) were taken.

[0029] Weigh 0.2 parts of modified cellulose ether, 4 parts of redispersible latex powder, 0.8 parts of waterproofing agent (compounded with silicone waterproofing agent and calcium stearate waterproofing agent in a mass ratio of 2.2:1), 0.2 parts of retarder (compounded with sodium citrate and sodium gluconate in a mass ratio of 1.2:1), and 0.4 parts of early strength agent (compounded with calcium sulfate whisker and calcium nitrate in a mass ratio of 3.5:1);

[0030] S2: Preparation of additive pre-dispersion liquid: After the additive is preliminarily dispersed in an ultrasonic device (22kHz, 4.5 minutes), it is stirred in a stirrer at 1300r / min for 4.5 minutes and the temperature is controlled at 26°C to form a pre-dispersion liquid;

[0031] S3: Mixing and stirring: gypsum and aggregate are first stirred at a low speed of 110 r / min for 2.8 minutes in a twin-shaft forced mixer. After the additive pre-dispersion liquid is added, the speed is increased to 260 r / min and stirred for 7.5 minutes. The amount of water mist sprayed is 1.2% of the total weight of the mortar to make a uniform mortar.

[0032] Embodiment 3:

[0033] S1: Raw material preparation, 35 parts of desulfurized gypsum, purity 85%, dried at 122℃ for 1.9 hours, fineness 155 mesh; 65 parts of recycled aggregate and natural sand composite, 24.7 parts of recycled aggregate (38% of the total aggregate), particle size 2-5mm, soaked in cement slurry for 2.8 hours (5% concentration), dried for 1.2 days. Natural sand accounts for 40.3 parts (62% of the total aggregate), particle size 0.15-1.5mm;

[0034] Weigh 0.4 parts of modified cellulose ether, 2.5 parts of redispersible latex powder, 0.4 parts of waterproofing agent (silicone waterproofing agent and calcium stearate waterproofing agent are compounded in a mass ratio of 2.8:1), 0.4 parts of retarder (sodium citrate and sodium gluconate are compounded in a mass ratio of 1.8:1), and 0.25 parts of accelerator (calcium sulfate whisker and calcium nitrate are compounded in a mass ratio of 2.5:1).

[0035] S2: Preparation of additive pre-dispersion liquid: After treatment with an ultrasonic device (28kHz, 3.5 minutes), stirring in a stirrer at 1400r / min for 5.5 minutes at a temperature of 27°C, a pre-dispersion liquid was obtained;

[0036] S3: Mixing and stirring. The gypsum and aggregate are first stirred at a low speed of 130 r / min for 2.2 minutes. After adding the pre-dispersed liquid, they are stirred at 290 r / min for 6.5 minutes. The amount of water mist sprayed is 1.8% of the total weight of the mortar to obtain a uniform mortar material.

[0037] The present invention and its implementation methods are described above, and such description is not restrictive. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design structures and embodiments similar to the technical solution without creativity, which should all fall within the protection scope of the present invention.

Claims

1. A gypsum-based mortar material, characterized in that: The composition includes the following components by weight: 30-60 parts of gypsum, 30-65 parts of aggregate, 0.1-0.5 parts of modified cellulose ether, 2-5 parts of redispersible latex powder, 0.2-1 parts of waterproofing agent, 0.1-0.5 parts of retarder and 0.2-0.5 parts of early strength agent.

2. A gypsum-based mortar material according to claim 1, characterized in that: The gypsum is desulfurized gypsum with a purity of more than 85%.

3. A gypsum-based mortar material according to claim 1, characterized in that: The aggregate is a composite aggregate of quartz sand and light ceramsite, wherein the quartz sand has a particle size of 0.1-1.5 mm, accounting for 40-60% of the total aggregate, and the light ceramsite has a particle size of 2-5 mm, accounting for 40-60% of the total aggregate.

4. The gypsum-based mortar material according to claim 1, characterized in that: The waterproofing agent is a composite waterproofing agent of an organosilicon waterproofing agent and a calcium stearate waterproofing agent in a mass ratio of 2:1 to 3:

1.

5. The gypsum-based mortar material according to claim 1, characterized in that: The retarder is a compound retarder of sodium citrate and sodium gluconate, and the mass ratio of the two is 1:1-2:

1.

6. The gypsum-based mortar material according to claim 1, characterized in that: The early strength agent is a compound of calcium sulfate whiskers and calcium nitrate in a mass ratio of 2:1-4:

1.

7. A method for preparing a gypsum-based mortar material according to any one of claims 1 to 6, characterized in that: The steps include: S1: Selection and treatment of gypsum: Industrial desulfurized gypsum is used, and the gypsum is dried in a rotary dryer at 120-130° C. for 1.5-2 hours. A breaking device is provided inside the dryer to break up the gypsum lumps during the drying process, thereby improving the drying efficiency and reducing the subsequent grinding energy consumption. The dried gypsum is ground with a vertical mill to a fineness of 150-180 meshes; S2: Selection and preparation of aggregate: Aggregates are a composite system of recycled aggregates and natural sand. The recycled aggregates are obtained by crushing and screening concrete blocks and bricks from construction waste, with a particle size of 2-5 mm, accounting for 30%-40% of the total aggregates. Natural sand is medium-coarse sand with a particle size of 0.15-1.5 mm, accounting for 60%-70% of the total aggregates. Soak the recycled aggregate in an aqueous solution containing 5%-8% cement slurry for 2-3 hours to adhere a layer of cement slurry to the surface of the recycled aggregate, then remove it and dry it in the natural environment for 1-2 days. This treatment can improve the bonding strength between the recycled aggregate and the gypsum matrix and make up for the defect of insufficient strength of the recycled aggregate itself; S3: Preparation of additive pre-dispersion liquid: After accurately weighing the modified cellulose ether, redispersible latex powder, waterproofing agent, retarder and early strength agent according to weight, put them into an ultrasonic device, set the ultrasonic frequency to 20-30kHz, and treat for 3-5 minutes to disperse the additives preliminarily, then put them into a mixer and stir them at a high speed of 1000-1500r / min for 4-6 minutes to form an additive pre-dispersion liquid. During the stirring process, the temperature inside the equipment is controlled at 25-30°C to prevent excessive heat generated by high-speed stirring from causing changes in the performance of the additives; S4: Mixing and stirring: Add the treated gypsum and composite aggregate into a twin-shaft forced mixer, first stir at a low speed (100-150r / min) for 2-3 minutes to make the materials initially mixed and evenly mixed, then slowly add the additive pre-dispersion liquid into the mixer, and at the same time increase the mixer speed to 250-300r / min and stir for 6-8 minutes until the material becomes a uniform mortar. During the stirring process, spray a small amount of water mist into the mixer through a spray device (the amount of water mist is 1%-2% of the total weight of the mortar) to replenish the water loss caused by stirring and ensure the working performance of the mortar.