CN115157443B - A device suitable for preparing water-based foam and mixing it with cement slurry - Google Patents

Abstract

The application discloses a device suitable for preparing water-based foam and mixing the water-based foam with cement paste, which comprises a gas cylinder, a flask, a foam chamber and a stirring cylinder, wherein inert gas is filled in the gas cylinder, a gas outlet of the gas cylinder is sequentially communicated with a gas inlet pipe and a T-shaped three-way pipe, the other two ends of the T-shaped three-way pipe are respectively communicated with a foaming liquid inlet pipe at the opening of the flask and an open pipeline at the left lower end of the foam chamber, foaming liquid is filled in the flask, a plurality of layers of porous media with gradually increased porosity are arranged in the foam chamber, a filler is arranged between adjacent layers of porous media, a discharge pipe is arranged at the bottom of the foam chamber, a foam outlet pipe is arranged at the middle upper end of the foam chamber, the foam outlet pipe is communicated with the stirring cylinder, a slurry inlet is arranged at the upper end of the stirring cylinder for inputting cement paste, and a slurry outlet is arranged at the lower end of the stirring cylinder. The device is used for preparing uniform, fine and stable carbon dioxide water-based foam, low foam breaking rate, large contact area and uniformly mixed foam cement slurry.

Description

A device suitable for preparing water-based foam and mixing it with cement slurry

technical field

The invention belongs to the field of foaming equipment and stirring equipment, in particular to a device suitable for preparing water-based foam and mixing it with cement slurry.

Background technique

Under the same water-cement ratio, the foam cement slurry has lower permeability and higher strength. Foam cement slurry with different specific gravity can fully meet the requirements of different working performances such as compressive strength, permeability and fluidity. Foam cement slurry has been widely used as a new type of material. At the same time, due to fuel combustion and clinker calcination in cement production, a large amount of environmentally polluting gases will be produced, such as carbon dioxide gas. In order to reduce carbon emissions in the air and protect the environment, we try to use these gases to make water-based foams, so as to prepare lightweight The method of preparing foam synchronous grouting grout from light foam cement slurry and achieving good results. However, most of the water-based foams prepared by the existing foaming equipment do not have a uniform foam structure, a high expansion ratio and a certain stability time, and the prepared water-based foams cannot meet the quality requirements required by the project. At the same time, the existing mixing When the equipment is mixed and stirred, it is mostly added at one time. When the two are mixed, the foam is easy to break when mixed, the foam breaking rate is high, the contact area between the water-based foam and the cement slurry is small, and the properties of the foamed cement slurry obtained by mixing and stirring are not good. To meet the engineering requirements, manual mixing is often required in order to obtain good quality foamed cement slurry for experiments. At the same time, the current technology can hardly achieve the same pace of foaming and mixing, that is, after foaming is completed, the foam is added to the cement slurry at the same time. Feed into the mixer to ensure less material loss and less equipment wear.

Therefore, there is a need for a foaming equipment that can prepare fine, uniform, and stable water-based foam and a mixing equipment that has a simple structure, less foam breakage during mixing and mixing, and a large contact area between foam and cement slurry, and at the same time, it is necessary to ensure that both work In step.

Contents of the invention

The technical problem to be solved by the present invention is to provide a device suitable for preparing water-based foam and mixing it with cement slurry. The device provides the gas required for preparing foam through different gas cylinders; Foam liquid; fine, stable and uniform water-based foam is prepared through a foamer; the prepared water-based foam and cement slurry are mixed and stirred through a mixer to obtain a low foam breaking rate, a large contact area between the foam and the cement slurry, and various properties Foam cement slurry that can meet the needs of the project; control the foaming and mixing steps through the designed working steps. In addition, the structure design of the device is simple and the cost is low.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A device suitable for preparing water-based foam and mixing it with cement slurry, including a gas cylinder, a flask, a foam chamber and a mixing drum, the gas cylinder is filled with inert gas, and the gas outlet of the gas cylinder is sequentially connected with the The gas inlet pipe is communicated with the T-shaped tee pipe, and the other two ends of the T-shaped tee pipe are respectively connected with the foaming liquid inlet pipe at the opening of the flask and the open pipe at the lower left end of the foam chamber. Foaming liquid, the flask is provided with a constant temperature heater, the foam chamber is provided with multi-layer porous media with gradually increasing porosity, fillers are arranged between adjacent layers of porous media, and the foam chamber The bottom is provided with a discharge pipe, the middle and upper end of the foam chamber is provided with a foam outlet pipe, the air outlet of the gas cylinder is provided with a cylinder valve, the outlet of the flask is provided with a flask valve, and the foam outlet pipe A foam outlet pipe valve is provided at the center, and the foam outlet pipe is connected with the mixing drum. The upper end of the mixing drum is provided with a slurry inlet for inputting cement slurry, and the lower end of the mixing drum is provided with a slurry outlet.

Further, the mixing drum is placed horizontally, and a horizontally placed hollow screw rod is arranged inside the mixing drum. Both the mixing drum and the hollow screw rod are connected to the rotating shaft of the bearing, and the bearing is powered by a motor. The foam outlet pipe extends into the mixing drum, and the foam outlet pipe communicates with the hollow screw rod, and the hollow screw rod is evenly provided with round holes for foaming.

Preferably, the bearing includes an inner rotating shaft and an outer rotating shaft that rotate in opposite directions, the inner rotating shaft is connected with the hollow screw rod, the outer rotating shaft is connected with the mixing drum, and the hollow screw rod The outer wall is provided with several inner shaft blades, and the inner wall of the mixing drum is provided with several outer shaft blades.

Preferably, the inner shaft blade is a helical stainless steel blade, and the outer shaft blade is a rectangular stainless steel blade.

Preferably, the porous medium is a multi-layer steel wire mesh, and the filler is steel wool, which is evenly filled between adjacent layers of steel wire mesh.

Further, a density detector and a pH detector are installed on the upper right part of the mixing drum, and an air pressure controller is installed on the gas cylinder.

Further, the mixing drum is provided with a rectangular hole, and a rectangular plate is hinged on the outer side of the mixing drum close to one side of the rectangular hole, and the pH detector is detachably arranged on the inner side of the rectangular plate. The outer side of the mixing drum is fixed with bumps near the other three sides of the rectangular hole, the bumps are provided with grooves, and the inner side of the rectangular plate is provided with a 3/4 ring protruding ring, the protruding ring and The grooves are adapted, the protruding ring is provided with a locking hole, and the protrusion is provided with a lock, and the locking hole is adapted to the locking buckle.

Preferably, the reading of the air pressure controller is 0.2kpa, and the foaming liquid adopted in the flask includes the foaming agent tea saponin of 4g/L, the foam stabilizer lauryl of 5g/L, 2g/L The thickener is sodium polyacrylate, and the temperature of the constant temperature heater is set to 25 degrees Celsius.

Further, the method for preparing foam cement slurry is:

Step A: Inject inert gas into the foaming liquid to prepare foam, calculate the expansion ratio Y of the foaming liquid, and mix the prepared foam with cement slurry according to the foam slurry ratio of 5:1 to obtain foam cement slurry for testing , and measure the foam cement slurry density Z;

Step B: Calculate the amount of foam required for the experiment based on the amount X of the foamed cement slurry prepared in the experiment and the density Z of the foamed cement slurry, the amount of foam is 0.83X, and the foaming liquid is made accordingly;

Step C: Fill the gas cylinder with inert gas, close the valve of the gas cylinder, and adjust the air pressure controller so that the air pressure in the gas cylinder is 0.2kpa;

Step D: Connect the gas cylinder with the gas inlet pipe, then connect the gas inlet pipe with the T-shaped tee pipe, and then connect the other two branches of the T-shaped tee pipe with the foaming liquid inlet pipe and the foaming liquid inlet pipe at the opening of the flask respectively. The open pipe at the lower left end of the chamber is connected, and the valve of the flask is closed;

Step E: Based on the amount of foam required for the experiment in step B, select a foam chamber with a suitable volume to communicate with the T-shaped tee pipe;

Step F: Simultaneously open the gas cylinder valve and the flask valve, close the foam outlet pipe valve, and prepare foam;

Step G: The inert gas is pushed by the air pressure, and the foam enters the foam chamber and gradually rises, passing through the porous medium and the filler;

Step H: as the porosity gradually increases, the foam pore size becomes larger and uniform;

Step I: Obtain fine, stable and uniform water-based foam, which is stored inside the foam chamber;

Step J: Calculate the water, cement, and light magnesia required for mixing based on the foam slurry ratio of 5:1 and water-cement ratio of 1:2.4, light magnesium oxide 15%, fly ash 25%, and cement 60%. and the amount of fly ash and its preparation;

Step K: mixing and stirring water, cement, light magnesia and fly ash to prepare cement slurry;

Step L: Open the valve of the foam outlet pipe, and pour the prepared cement slurry into the slurry inlet;

Step M: Turn on the motor, the hollow screw rod rotates clockwise, the mixing drum rotates counterclockwise, the foam is discharged from the foam hole, and moves forward in a spiral together with the cement slurry;

Step N: read the density of the foamed cement slurry according to the reading of the density detector;

Step 0: read the pH value of the foamed cement slurry according to the pH detector;

Step P: The prepared foamed cement slurry is discharged from the slurry outlet, and the motor is turned off;

Step Q: Obtain the required foam cement slurry.

Preferably, the calculation formula in the process of preparing foamed cement slurry is:

C=0.426X×Z

D=0.1775X×Z

E=0.1065X×Z

Among them, X is the volume of the foamed cement slurry planned for the experiment, Y is the foaming ratio of the foaming liquid, Z is the density of the foamed cement slurry measured by the test, K is the density of the foaming liquid, and A is the required density of the experiment. The volume of foaming liquid, B is the quality of water required for mixing cement, C is the required quality of cement, D is the required quality of fly ash, and E is the required quality of light magnesium oxide.

Compared with the prior art, the present invention has the following beneficial effects:

The technical problem to be solved by the present invention is to provide a device suitable for preparing water-based foam and mixing it with cement slurry. The device provides the gas required for preparing foam through different gas cylinders; Foam liquid; fine, stable and uniform water-based foam is prepared through a foamer; the prepared water-based foam and cement slurry are mixed and stirred through a mixer to obtain a low foam breaking rate, a large contact area between the foam and the cement slurry, and various properties Foam cement slurry that can meet the needs of the project; control the foaming and mixing steps through the designed working steps. In addition, the structure design of the device is simple and the cost is low.

Description of drawings

Fig. 1 is a kind of schematic diagram of the device that is suitable for preparing water-based foam and mixing it with cement slurry of the present invention;

Fig. 2 is a schematic diagram inside the foam chamber of the present invention;

Fig. 3 is the style and measurement principle of the self-made pH meter of the present invention.

1-gas cylinder, 2-air pressure controller, 3-gas cylinder valve, 4-gas inlet pipe, 5-T-type tee pipe, 6-flask, 7-constant temperature heater, 8-flask valve, 9-foaming Liquid inlet pipe, 10-foam chamber, 11-porous medium, 12-filler, 13-discharge pipe, 14-foam outlet pipe, 15-foam outlet pipe valve, 16-bearing, 17-slurry inlet, 18- Inner shaft blade, 19-foaming round hole, 20-outer shaft blade, 21-stirring drum, 22-hollow screw rod, 23-density detector, 24-pulp outlet, 25-PH detector, 26-motor.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Example 1

The embodiment of the present invention provides a kind of foaming and mixing equipment, as shown in Figure 1, wherein the equipment for providing gas is a gas cylinder 1, and the gas cylinder 1 is equipped with an air pressure controller 2 and a gas cylinder valve 3; the equipment for providing foaming liquid It is a flask 6 equipped with a constant temperature heater 7, a movable bottom plate and a flask valve 8; the foaming equipment includes a gas inlet pipe 4, a foaming liquid inlet pipe 9, a T-shaped tee pipe 5, a foam chamber and a movable bottom plate 10, Porous medium 11, filler 12, discharge pipe 13, foam outlet pipe 14 and foam outlet pipe valve 15; said equipment provides gas raw material for foaming through said gas cylinder 1, and the air pressure during ventilation is controlled based on air pressure controller 2, Control the venting speed based on the cylinder valve 3, feed gas based on the gas inlet pipe 4, store the foaming liquid based on the flask 6, control the temperature of the foaming liquid based on the constant temperature heater 7, and control the flask based on the movable bottom plate 6 switches, based on the flask valve 8 to control the speed of feeding the liquid, based on the foaming liquid inlet pipe 9 into the foaming liquid, based on the T-shaped tee pipe 5 the gas inlet pipe 4, the foaming liquid inlet pipe 9 , the foaming cylinder is connected, based on the foam chamber and its movable floor 10 to store the prepared water-based foam, based on the porous medium 11 and the filler 12, the prepared foam is fine, uniform and stable, based on the foaming cylinder Carry out the whole process of foaming, the discharge pipe 13 can discharge the diluent that is not fully foamed, discharge the liquid that is not completely foamed based on the discharge pipe 13, and feed the foam into the mixer based on the foam outlet pipe 14, based on the The foam outlet pipe valve 15 controls the passage time.

As shown in Figure 2, a movable baffle is set at the bottom of the foam chamber 10, and a valve is set on the foam outlet pipe 14, so that the foam can be stored in the foam chamber preferably, and the valve can be opened after the cement slurry is mixed, which can precisely control Foam and cement slurry are passed into the mixer at the same time, effectively reducing material loss and equipment wear. The foam chambers 10 have various volumes, and the foam chambers 10 are detachable, and the foam chambers 10 with different volumes can be accurately selected and installed in the foam generator according to the amount of foam required by the project. A piston is provided on the left side of the foam chamber 10, and a scale is provided on the surface. After the valve is opened, the foam can be precisely pushed into the subsequent mixer by compressing the piston.

Specifically, the air pressure controller 2 is arranged on the upper left side of the gas cylinder 1, the gas cylinder valve 3 is located at the outlet of the gas cylinder 1, the gas cylinder 1 is connected to the gas inlet pipe 4, and the gas cylinder 1 The right side of the inlet pipe 4 is connected to the left end of the T-shaped tee pipe 5 , and the gas cylinder 1 is fed with required gas based on the gas inlet pipe 4 . The thermostatic controller 7 is arranged on the outside of the flask 6, the flask valve 8 is arranged at the outlet of the flask 6, the flask 6 is connected to the foaming liquid inlet pipe 9, and the foaming liquid inlet pipe 9. The lower part is connected to the upper guide port of the T-shaped tee pipe 5, and the right guide port of the T-shaped tee pipe 5 is connected to the foaming tube to complete the feeding and foaming of raw materials; The foam cylinder is placed vertically (the gas-liquid movement direction is opposite to the gravity direction of the steel plate), the bottom is the discharge pipe 13, the interior is the filler 12 and the porous medium 11, and the top is the foam chamber and its baffle 10 , the vertically placed gas-liquid flow direction is opposite to the direction of gravity, which is equivalent to introducing a bubbling effect, which is beneficial to the generation of foam. The arrangement of the T-shaped three-way pipe 5 has a simple structure, is easy to process and manufacture, and has low cost. It can simultaneously pass gas and foaming liquid into the foamer to control the quality of the obtained foam.

Preferably, the flask 6 is inverted, and the side wall of the flask is marked with scales, so that it is relatively easy and convenient to feed the foaming liquid, and the volume of the foaming liquid can be precisely controlled.

Further, the gas filled in the gas cylinder 1 is carbon dioxide, the reading of the air pressure controller 2 is adjusted to be 0.2kpa, the foaming liquid ratio adopted in the flask 6 is tea saponin 4g/L, and the selected foam stabilizer ratio is ten Dialkyl 5g/L, thickener is sodium polyacrylate 2g/L, regulates thermostatic heater 7 and temperature is controlled constant at 25 degrees centigrade, provides carbon dioxide gas by cylinder 1, provides institute's foaming liquid by flask 6, both Mix to foam. The foaming liquid is non-toxic and pollution-free.

Further, the filler 12 is steel wool, and the porous medium 11 is steel wire mesh. The steel wire mesh is provided with three layers, and the apertures of the steel wire mesh are 0.1 mm, 0.5 mm, and 1.0 mm from bottom to top. Steel wool is filled between the steel wire mesh. A steel wire mesh is arranged in the foam chamber 10, steel wool is filled between the steel mesh, the porosity of the steel mesh increases gradually, and the simultaneous action of the steel mesh and the steel wool can form a turbulent vortex, and as the porosity gradually increases, The foam cells become larger and uniform. The porous medium 11 is made of steel wire mesh, and the filler 12 is made of steel wool, which comprehensively considers the engineering effectiveness and economic applicability.

The mixing equipment of the present invention comprises a bearing 16, a pulp inlet 17, an inner shaft blade 18, a bubble hole 19, an outer shaft blade 20, a mixing drum 21, a hollow screw rod 22, a density detector 23, a pulp outlet 24, a pH Detector 25, motor 26. The mixing device controls the rotation of the mixing drum 21 and the hollow screw 22 through the bearing 16, introduces the cement slurry that is not mixed with the foam through the slurry inlet 17, and makes the foamer through the foaming circular hole 19. The prepared foam flows out, and the cement slurry and foam are mixed and stirred by the inner shaft blade 18 and the outer shaft blade 20, and the blade is rotated by the rotation of the mixing drum 21 and the hollow screw rod 22, and is discharged through the slurry outlet 24 The prepared carbon dioxide foam cement slurry is powered by the motor 26 to drive the mixing drum and the hollow spiral, and the related properties of the foam are measured by the density detector 23 and the pH detector 25 .

Specifically, the mixing drum 21 is placed horizontally as a whole, and the left end is connected to the foam outlet pipe 14 in the foaming equipment. The hollow screw rod 22 is located inside and connected to the right end of the foam outlet pipe 14. 19 is evenly arranged on the hollow screw rod 22, and the right end of the mixing drum 21 is provided with a motor 26. The slurry inlet 17 and the slurry outlet 24 are respectively located at the upper left part and the lower right part of the mixing drum. The density detector 23 and the pH detector 25 are respectively arranged inside the mixing drum, and are located at the upper part of the rightmost end of the mixing drum.

The inner shaft blade 18 is arranged outside the hollow screw rod 22 , and the outer shaft blade 20 is arranged inside the mixing drum 21 .

The bearing 16 is divided into two types: an internal bearing and an external bearing, wherein the internal bearing controls the rotation of the hollow screw rod 22 , and the external bearing controls the rotation of the mixing drum 21 . Power is provided by the motor 26, the hollow screw rod 22 and the mixing drum 21 are controlled to rotate in the opposite direction through the bearing 16, and the inner shaft blade 18 and the outer shaft blade 20 are driven to rotate, and the cement slurry is injected through the slurry inlet 17, The foam is precipitated through the foaming hole 19, the cement slurry and the foam are mixed and stirred by the rotation of the inner shaft blade 18 and the outer shaft blade 20, and the resulting carbon dioxide foam cement slurry is discharged through the slurry outlet 24, and is detected by the density detector 23 and the pH A meter 25 was used to measure the related properties of the prepared foam cement slurry.

Internal and external bearings respectively control the rotation of the hollow screw rod 22 and the mixing drum 21, improving the stability of the device. The motor 26 is used to control the rotation of the hollow screw rod 22 and the mixing drum 21, which reduces manpower consumption. There is a foaming circular hole 19 in the pitch center of each spiral blade as the foam outlet, which increases the contact area between the foam and the cement slurry, makes the foam evenly distributed, and reduces the foam breaking rate. The hollow screw rod 22 and the mixing drum 21 rotate in opposite directions, which also increases the contact area between the foam and the cement slurry, and improves the mixing uniformity of the foam and the slurry. The inner shaft blade adopts spiral shape, which significantly improves the stirring efficiency, increases the contact area, and reduces the foam breaking rate. Both the inner and outer shaft blades are made of stainless steel, which reduces the possibility of rust and strength decline after long-term contact with the foam.

Further, the hole diameter of the foaming circular hole 19 is 1.0 mm, so that the previously prepared foam is separated out.

Further, the inner shaft blade 18 is helical, the outer shaft blade 20 is rectangular, and the materials used are all stainless steel, which can increase the stirring area, reduce the foam breaking rate, improve the stirring efficiency and prevent the blade from rusting and reduce the strength. .

Further, the rotation direction of the mixing drum 21 is counterclockwise, and the rotation direction of the hollow screw rod 22 is clockwise. It also increases the stirring contact area and makes the mixing more uniform and sufficient.

Further, the density detector 23 is a tuning fork densitometer, the model of the tuning fork densitometer is LDS-2100 tuning fork densitometer, and the measuring range of density is 0-3g/cm3. The pH meter adopts pH test paper to measure the pH value of the foam cement slurry.

As shown in FIG. 3 , the pH tester 25 can be detachably placed in the mixing tank 21 . Preferably, the mixing drum 21 is provided with a rectangular hole, and the outside of the mixing drum 21 is hinged with a rectangular plate near one side of the rectangular hole, and the pH detector 25 is detachably arranged on the rectangular plate. Inside, the outside of the mixing drum 21 is fixedly provided with bumps near the other three sides of the rectangular hole. The protruding ring is adapted to the groove, the protruding ring is provided with a lock hole, and the protrusion is provided with a lock catch, and the lock hole is adapted to the lock catch. The setting of the supporting structure ensures the airtightness, and at the same time, the pH tester 25 can be detachable.

Example 2

Usually, we use a turbo foamer to prepare CO2 water-based foam, and manually mix the cement slurry and CO2 water-based foam by manual method. The foam prepared by this method is not uniform and stable enough, and it is very easy to break. At the same time, the contact between the cement slurry and the foam is not sufficient when mixing and stirring. The invention improves the manufacturing of foaming and mixing equipment for foaming and stirring, and the quality of the prepared foam is improved. However, because the cement slurry cannot be fed into the mixer simultaneously when the foam enters the mixer, and there is no formula for quantitative calculation, this results in a large amount of material waste and excessive wear and tear on equipment. Thus, the device is further improved, and the raw materials required for the calculation formula are obtained. The whole process of the improved work is as follows:

Step A: select whipping agent tea saponin, the amount of tea saponin is 4g/L, foam stabilizer dodecyl, the amount of dodecyl is 5g/L, thickener is sodium polyacrylate, polyacrylic acid The amount of sodium is 2g/L to prepare a foaming liquid, the temperature of the foaming liquid is fixed at 25 degrees Celsius, a small amount of foam is prepared by feeding carbon dioxide gas, and the foaming ratio Y of the foaming liquid is calculated accordingly. The prepared foam was mixed with cement slurry according to the foam slurry ratio of 5:1 to obtain foam cement slurry, and its density Z was measured.

Step B: Determine the amount X of the foam cement slurry required for the experiment, calculate the amount of foam required for stirring according to the density Z of the foam cement slurry obtained in the experiment in the previous step A, and the foam slurry ratio is 5:1, and select the foaming agent tea soap Plain, the amount of tea saponin is 4g/L, foam stabilizer lauryl, the amount of lauryl is 5g/L, thickener is sodium polyacrylate, and the amount of sodium polyacrylate is 2g/L. According to step A, the foaming rate of the foaming liquid is Y, and quantitatively make the foaming agent diluent accordingly, open the movable baffle at the bottom of the flask 6, pass it into the flask 6, close the baffle, close the valve, and turn on constant temperature heating Keep the temperature constant at 25°C.

Step C: The gas filled in the gas cylinder 1 should be inert. In order to explore the various properties of the carbon dioxide foam cement slurry in this experiment, choose carbon dioxide as the gas used for foaming, obtain the corresponding gas cylinder, and adjust the air pressure controller , control the air pressure to 0.2kpa, and close the valve.

Step D: The gas inlet pipe 4 is connected to the T-shaped tee pipe 5, the gas inlet pipe 4 is connected to the gas cylinder; the foam chamber 10 is connected to the branch pipe of the T-shaped tee pipe 5, and the other branch of the T-shaped tee pipe 5 Branch pipe is connected with flask 6;

Step E: The volume of each foam chamber 10 is different. According to the previous step B, the amount of foam required for this experiment can be known. Based on this, select a foam chamber with a suitable volume for installation, and pull the piston on the left side of the foam chamber to the far left side.

Step F: Simultaneously open the valves of the gas cylinder and flask 6, open the movable baffle at the bottom of the foam chamber, close the valve at the foam inlet pipe, control the flow rate of the gas and liquid, and start foaming.

Step G: The diluted blowing agent solution and a certain gas under certain pressure enter the lower part of the foaming cylinder, the porous medium 11 and the filler 12, the foam gradually rises in the foaming cylinder, and the baffle at the bottom of the foam chamber is opened.

Step H: With the gradual increase of porosity, the foam pore size becomes larger and uniform.

Step I: To obtain fine, stable and uniform water-based foam, close the baffle at the bottom of the foam chamber so that the foam is stored inside the foam chamber. At this point, the foaming process is over, and we get the carbon dioxide water-based foam required for the experiment and store it inside the foam chamber, then the cement slurry is stirred, and it is mixed with the foam synchronously.

Step J: The amount X of the foam cement slurry required for the experiment was determined in the previous step B, through the ratio of foam slurry 5:1 and water-binder ratio 1:2.4 and the proportion of various cementitious materials - light magnesium oxide 15% , fly ash 25%, cement 60%, calculate the amount of water, cement, light magnesia and fly ash required for mixing and mixing and prepare them.

Step K: mixing water with cement and other materials to obtain cement slurry.

Step L: Open the valve at the foam inlet pipe, slowly push the piston according to the experimental requirements, so that the foam enters the mixer, and at the same time pour the previously prepared cement slurry into the slurry inlet of the mixer, and turn on the motor.

Step M: The motor rotates the hollow screw rod clockwise, which makes the mixing drum rotate counterclockwise, and the foam is discharged from the foaming hole and moves forward in a spiral with the cement slurry; the spiral inner shaft blade and the rectangular outer shaft blade are mixed in the opposite direction at the same time .

Step N: Read the density of the foamed cement slurry according to the reading of the tuning fork concentration meter

Step O: Open the side wall of the mixer at the pH detector, take out the pH test paper fixed on the side wall, and read the pH value of the foam cement slurry according to the color of the test paper.

Step P: The prepared foam cement slurry is discharged from the slurry outlet, and the motor is turned off.

Step Q: Obtain the required foam cement slurry.

Calculate the amount of water, cement, fly ash, light magnesia and foaming liquid required for this experiment by the following formula:

C=0.426X×Z

D=0.1775X×Z

E=0.1065X×Z

Among them, X is the volume of the required foam cement slurry determined before the experiment, Y is the foaming ratio of the foaming liquid, Z is the density of the foam cement slurry read by the densitometer in the previous experiment, and K is the density of the foaming liquid , A is the volume of foaming liquid required for the experiment, B is the quality of water required for mixing cement, C is the required quality of cement, D is the required quality of fly ash, and E is the required quality of light magnesium oxide.

The water-based foam prepared by the invention has a uniform foam structure, a relatively high expansion ratio and a certain stable time.

After optimizing the proportion of each material component based on the two most important performance indicators of compressive strength and density, the mechanical properties of the carbon dioxide foam composite cement slurry were measured, including stone formation rate, water separation rate, setting time and fluidity, and the performance of the foamed cement slurry was compared. The standard analyzes the applicability of carbon dioxide foam cement slurry grouting. The setting time is measured by a typical Vicat instrument, and the fluidity is measured by the truncated cone circular mold method. The test results are shown in the following table:

Table 1 Determination of mechanical properties of foam composite cement slurry

It can be seen from the table that the compressive strength of the carbon dioxide foam cement stone body modified by the external admixture far exceeds the strength standard of foam cement, and is higher than that of ordinary cement stone body, and the density, stone rate and water separation rate all meet the requirements of foam cement slurry The initial setting time of foam cement is 146 minutes, and the final setting time is 413 minutes, which meets the setting time requirements. It is longer than the initial setting time of 45 minutes and the final setting time of 390 minutes for ordinary cement grout, because a large amount of free water in the slurry is stored in the liquid film of the foam system , free water precipitates after the foam dissipates, which prolongs the hydration process. At the same time, the existence of foam makes the sample more loose and porous, prolonging the moving path of water; the average fluidity is 21cm, which meets the fluidity requirements of foam cement, which is higher than that of ordinary cement slurry The fluidity of 16-18cm increased by about 20%, indicating that the incorporation of water-based foam increased the fluidity of the slurry material.

The embodiment of the present invention provides a foaming and mixing equipment. The equipment prepares carbon dioxide water-based foam through a foamer, and mixes and stirs the carbon dioxide water-based foam and cement slurry through a mixer, and finally obtains carbon dioxide foam cement slurry for use in On-site engineering reduces carbon dioxide emissions and provides new light-weight, high-strength materials for on-site construction, which are low-cost and environmentally friendly.

In general, the mixing equipment has the characteristics of less foam breakage, simple structure, uniform mixing and continuous production of large flow foam cement slurry. At the same time, the equipment uses the storage function of the foam chamber to allow foam and cement slurry to enter the mixer at the same time for mixing. , less material loss and equipment wear.

In actual engineering, the effect of the foamed cement slurry produced mainly depends on two core components, the foamer and the mixer. The present invention redesigns the porous foamer, and there are few designs in the prior art in this regard. A two-way stirring mixer is designed, which is more suitable for practical engineering;

In this application, through the design of the foamer and the mixer, uniform, delicate and stable carbon dioxide water-based foam can be prepared, as well as foam cement slurry with low foam breaking rate, large contact area and uniform mixing. At the same time, the equipment has the advantages of simple structure, low cost, easy processing and high reliability, and the foamed cement slurry produced can meet the requirements of on-site construction.

Claims (5)

1. A method for preparing foam cement slurry based on a device suitable for preparing water-based foam and mixing it with cement slurry, characterized in that: The device suitable for preparing water-based foam and mixing it with cement slurry includes a gas cylinder (1), a flask (6), a foam chamber (10) and a mixing drum (21). Fill inert gas, the gas cylinder (1) is connected to the gas inlet pipe (4), the right side of the gas inlet pipe (4) is connected to the left end guide port of the T-shaped tee pipe (5), and the T-shaped The other two ends of the three-way pipe (5) communicate with the foaming liquid inlet pipe (9) at the opening of the flask (6) and the open pipe at the lower left end of the foam chamber (10) respectively, and the foaming liquid is housed in the said flask (6). Bubble liquid, described flask (6) is provided with constant temperature heater (7), is provided with multilayer porous medium (11) that porosity increases gradually in described foam chamber (10), adjacent layer porous medium ( 11) is provided with a filler (12), the bottom of the foam chamber (10) is provided with a discharge pipe (13), and the middle and upper end of the foam chamber (10) is provided with a foam outlet pipe (14), The gas outlet of the gas cylinder (1) is provided with a gas cylinder valve (3), the outlet of the flask (6) is provided with a flask valve (8), and the foam outlet pipe (14) is provided with a foam outlet Pipe valve (15), the foam outlet pipe (14) is in communication with the mixing drum (21), and the upper end of the mixing drum (21) is provided with a slurry inlet (17) for inputting cement slurry, and the mixing drum The lower end of (21) is provided with pulp outlet (24); The mixing drum (21) is placed horizontally, and a horizontally placed hollow screw rod (22) is provided in the mixing drum (21), and the mixing drum (21) and the hollow screw rod (22) are all connected to the bearing ( 16), the bearing (16) is powered by a motor (26), the foam outlet pipe (14) stretches into the mixing drum (21), and the foam outlet pipe (14) is connected to the The hollow screw rod (22) communicates with each other, and the bubble hole (19) is uniformly arranged on the hollow screw rod (22); The porous medium (11) is a multi-layer steel wire mesh, and the filler (12) is steel wool, which is evenly filled between the steel wire meshes of adjacent layers; The upper right part of the mixing drum (21) is provided with a density detector (23) and a pH detector (25), and the gas cylinder (1) is provided with an air pressure controller (2); The method for preparing foam cement slurry is: Step A: inject inert gas into the foaming liquid to prepare foam, calculate the expansion ratio Y of the foaming liquid, and mix the prepared foam with the cement slurry according to the foam slurry ratio of 5:1 to obtain the foam cement slurry for the test. And measure and obtain the density Z that test records foam cement slurry; Step B: Calculate the amount of foam required for the experiment based on the volume X of the foamed cement slurry prepared in the experiment and the density Z of the foamed cement slurry measured in the test, and make a foaming liquid accordingly; Step C: Fill the gas cylinder (1) with inert gas, close the gas cylinder valve (3), and adjust the air pressure controller (2) so that the gas pressure in the gas cylinder (1) is 0.2kpa; Step D: Connect the gas cylinder (1) to the gas inlet pipe (4), and then connect the gas inlet pipe (4) to the T-shaped tee pipe (5), and then connect the other two ends of the T-shaped tee pipe (5) Two branches are communicated with the foaming liquid inlet pipe (9) at the opening of the flask (6) and the opening pipeline at the lower left end of the foam chamber (10), and the flask valve (8) is closed; Step E: Based on the amount of foam required for the step B experiment, select a foam chamber (10) with a suitable volume to communicate with the T-shaped tee pipe (5); Step F: Simultaneously open the gas cylinder valve (3) and the flask valve (8), close the foam outlet pipe valve (15), and prepare foam; Step G: The inert gas is pushed by the air pressure, and the foam enters the foam chamber (10) and gradually rises, passing through the porous medium (11) and the filler (12); Step H: as the porosity gradually increases, the foam pore size becomes larger and uniform; Step I: Obtain delicate, stable, uniform water-based foam, stored in the inside of the foam chamber (10); Step J: Based on the volume X of the foamed cement slurry prepared in the experimental plan determined in step B, the foam slurry ratio is 5:1 and the water-binder ratio is 1:2.4 and the proportion of various cementitious materials - light magnesium oxide 15%, fly ash 25%, cement 60%, calculate the amount of water, cement, light magnesia and fly ash required for mixing and stirring and prepare them; Step K: mixing and stirring water, cement, light magnesia and fly ash to prepare cement slurry; Step L: Open the foam outlet pipe valve (15), and pour the prepared cement slurry into the slurry inlet (17); Step M: Turn on the motor (26), the hollow screw rod (22) rotates clockwise, the mixing drum (21) rotates counterclockwise, the foam is discharged from the foam hole (19), and moves forward in a spiral together with the cement slurry; Step N: read the density of the foamed cement slurry according to the reading of the density detector (23); Step 0: read the pH value of the foam cement slurry according to the pH detector (25); Step P: The prepared foamed cement slurry is discharged from the slurry outlet (24), and the motor (26) is turned off; Step Q: Obtain the required foam cement slurry; The calculation formula in the process of preparing foam cement slurry is: C=0.426X×Z D=0.1775X×Z E=0.1065X×Z F=0.83X Among them, X is the volume of the foamed cement slurry prepared by the experiment plan, Y is the foaming ratio of the foaming liquid, Z is the density of the foamed cement slurry measured by the test, K is the density of the foaming liquid, and A is the foaming ratio required for the experiment. Bubble liquid volume, B is the quality of water required for mixing cement, C is the required quality of cement, D is the required quality of fly ash, E is the required quality of light magnesium oxide, F is the amount of foam required for the experiment . 2. a kind of method for preparing foamed cement slurry based on being applicable to preparing water-based foam according to claim 1 and the device that mixes it with cement slurry, is characterized in that: The bearing (16) includes an inner rotating shaft and an outer rotating shaft that rotate in opposite directions, the inner rotating shaft is connected with the hollow screw rod (22), the outer rotating shaft is connected with the mixing drum (21), The outer wall of the hollow screw rod (22) is provided with several inner shaft blades (18), and the inner wall of the mixing drum (21) is provided with several outer shaft blades (20). 3. a kind of method for preparing foamed cement slurry based on being applicable to preparing water-based foam and the device that mixes it with cement slurry according to claim 2, is characterized in that: The inner shaft blade (18) is a helical stainless steel blade, and the outer shaft blade (20) is a rectangular stainless steel blade. 4. a kind of method for preparing foamed cement slurry based on being applicable to preparing water-based foam according to claim 3 and the device of mixing and stirring it with cement slurry, is characterized in that: The mixing drum (21) is provided with a rectangular hole, the outer side of the mixing drum (21) is hinged with a rectangular plate near one side of the rectangular hole, and the pH detector (25) is detachably arranged on the The inner side of the rectangular plate, the outer side of the mixing drum (21) is fixedly provided with protrusions near the other three sides of the rectangular hole, the protrusions are provided with grooves, and the inner side of the rectangular plate is provided with 3/4 A ring protruding ring, the protruding ring is adapted to the groove, a lock hole is arranged on the protruding ring, a lock catch is arranged on the protrusion, and the lock hole is adapted to the lock catch. 5. a kind of method for preparing foamed cement slurry based on being applicable to preparing water-based foam according to claim 4 and the device that mixes it with cement slurry, is characterized in that: The reading of described air pressure controller (2) is 0.2kpa, and the foaming liquid that adopts in described flask (6) comprises the whipping agent tea saponin of 4g/L, the foam stabilizer lauryl of 5g/L, The thickener sodium polyacrylate of 2g/L, the temperature of described constant temperature heater (7) is set as 25 degrees Celsius.