CN115594209A

CN115594209A - High-recovery-rate superfine calcium carbonate production process and system

Info

Publication number: CN115594209A
Application number: CN202211031901.8A
Authority: CN
Inventors: 项舜; 张清华; 庄涛; 汪志伟
Original assignee: Hangzhou Zhenghe Nano Technology Co ltd
Current assignee: Hangzhou Zhenghe Nano Technology Co ltd
Priority date: 2022-08-26
Filing date: 2022-08-26
Publication date: 2023-01-13
Anticipated expiration: 2042-08-26
Also published as: CN115594209B

Abstract

The invention discloses a production process and a system of superfine calcium carbonate with high recovery rate, the process comprises the following steps that a, raw materials of limestone are crushed into small blocks and then calcined to obtain a product A, B and A products are placed in a sealed space filled with humid air and are paved to be below 10cm in thickness, standing is carried out for a period of time to obtain a product B, C and B products pass through a vibrating screen (4) to obtain a product C, D and C products are added with water to prepare wet materials, pressurized carbon dioxide is introduced into the wet materials to obtain a product D, E and D products are dried to obtain a product E, f and E products are depolymerized and activated to obtain a finished product; in the step b, the humidity of the air in the sealed space is more than 70% of the saturated humidity; in the step d, the mass ratio of the product C to the water is 2:1 to 1:1. the invention has the advantages of low production cost, high production efficiency, long service life and high safety.

Description

High-recovery-rate superfine calcium carbonate production process and system

Technical Field

The invention belongs to the field of superfine calcium carbonate, and particularly relates to a high-recovery-rate superfine calcium carbonate production process and system.

Background

The superfine calcium carbonate refers to calcium carbonate with the average particle size of 0.02 mu m < d < 0.1 mu m, and can be widely applied to wires, leather cloth, molded products, hard tubes, special-shaped extrusion, floor tiles, films, EVA sponge, powder coating, synthetic resin, glaze, oil paint, emulsion paint and primary paint in the coating industry, shoes, wires and cables, tires, sponge, colloid paste, rubber lining, belt (610) hoses, paper making, industrial coating, filling and fuel coloring agents, toothpaste, cosmetics, food additives, acid neutralizers and the like in the rubber industry.

The existing production process of superfine calcium carbonate comprises the following steps of screening limestone from raw materials, calcining the limestone into calcium oxide, digesting the calcium oxide into calcium hydroxide in a water pool, introducing carbon dioxide into the calcium hydroxide to generate calcium carbonate precipitate, dehydrating, drying, depolymerizing and activating the calcium carbonate precipitate to obtain a finished product.

The applicant is engaged in the production of the superfine calcium carbonate for a long time, the raw materials are inspected, the component content in the raw materials is measured under the laboratory condition, the quantity of the superfine calcium carbonate which is obtained theoretically is calculated according to a chemical reaction formula, the deviation between the quantity of the superfine calcium carbonate which is obtained theoretically and the quantity of the superfine calcium carbonate which is obtained in the actual production process is found to be large, namely, under the existing production process of the superfine calcium carbonate, a large part of raw material components are not converted into the superfine calcium carbonate, the recovery rate is low (namely, the utilization rate is low), the raw material waste is caused, and the production cost is improved. In addition, because the calcium carbonate precipitate is thick slurry after dehydration, the water content is still very high, and a large amount of heat energy is needed for drying, so that the production cost is further increased.

Therefore, the existing production process of the superfine calcium carbonate has high production cost.

Disclosure of Invention

The invention aims to provide a high-recovery-rate superfine calcium carbonate production process and system. The invention has the advantages of low production cost, high production efficiency, long service life and high safety.

The technical scheme of the invention is as follows: a production process of superfine calcium carbonate with high recovery rate comprises the following steps,

a. the raw material of limestone is crushed into small blocks and then calcined to obtain A product,

b. placing product A in a sealed space filled with humid air, spreading to a thickness of less than 10cm, standing for a period of time to obtain product B,

c. sieving the product B with a vibrating screen to obtain a product C,

d. adding water into product C to obtain wet material, introducing pressurized carbon dioxide into the wet material to obtain product D, oven drying product E and product D to obtain product E,

f. and depolymerizing and activating the product E to obtain a finished product.

In the production process of the superfine calcium carbonate with high recovery rate, in the step b, the air humidity in the sealed space is more than 70% of the saturated humidity.

In the production process of the superfine calcium carbonate with high recovery rate, in the step d, the mass ratio of the product C to the water is 2:1 to 1:1.

the system for realizing the production process comprises a jaw crusher, a vertical kiln, a digestion tank, a vibrating screen, a stirrer, a carbonization device, a dryer, a depolymerizer and an activator; one side of the digestion tank is provided with an opening and closing door, a water mist spraying mechanism is arranged in the digestion tank, and an exhaust mechanism is arranged on the digestion tank.

In the system, the digestion tank is rectangular, a vertical movable plate is arranged in the digestion tank, a gap is formed between the movable plate and the bottom surface of the digestion tank, sliding blocks are arranged on two sides of the movable plate, and the sliding blocks are connected with the inner side wall of the digestion tank through sliding rails.

In the system, the two sides of the moving plate are respectively provided with an upper sliding block and a lower sliding block, the sliding rails are fixed on the inner side wall in the width direction of the digestion tank, and the moving plate is provided with a handle.

In the system, the carbonization device comprises a tank body which is horizontally placed, both ends of the tank body are hemispherical, one end of the tank body is provided with an air inlet valve, an air inlet end of the air inlet valve is provided with a pneumatic rotary joint, the other end of the tank body is provided with an inlet valve, and the tank body is provided with a rotary driving mechanism and an angle adjusting mechanism.

In the system, among the rotary driving mechanism includes the bottom plate, and the top of bottom plate is equipped with two roller bearings, and two roller bearings are located the bottom both sides of the jar body, and the both ends of roller bearing all are equipped with the high frame board fixed with the bottom plate, and the roller bearing rotates with high frame board to be connected, and one of them high frame board is passed and is equipped with the follower to the one end of roller bearing, is equipped with gear motor on the bottom plate, and gear motor's output is equipped with the action wheel, and the action wheel passes through the belt and connects the follower.

In the system, the roller is provided with at least two annular grooves, the bottom surface of each annular groove is provided with a plurality of teeth distributed circumferentially, the outer peripheral surface of the tank body is provided with annular racks, the number of the racks is the same as that of the annular grooves on the roller, and the racks are meshed with the teeth.

In the system, the bottom plate is provided with a support positioned on one side of the tank body, the support is provided with a thrust bearing connected with the tank body, the feeding valve penetrates through an inner hole of the thrust bearing, and the support is provided with a through hole penetrated by the feeding valve.

In the system, the angle adjusting mechanism comprises a frame located below the bottom plate, one end of the bottom plate close to the feeding valve is hinged to the frame, an oil cylinder is arranged on the frame, the rear end of the oil cylinder is hinged to the frame, and the output end of the oil cylinder is hinged to the bottom plate.

Compared with the prior art, the invention has the advantages that,

firstly, in the prior art, a limestone raw material is screened to remove impurities such as 'old lime blocks' and silica gravel inside, and then the screened raw material is subjected to subsequent process steps, but the 'old lime blocks' also contain lime components and are removed together. The screening step is added in the step c, the limestone raw material forms a loose product B after being calcined and moistened, after the product B shakes on the vibrating screen, impurities can be well and relatively well screened out, particularly, effective components in the old ash blocks are reserved and utilized, the recovery rate is improved, the specific recovery rate cannot be calculated, because the content of the old ash blocks in the limestone raw material purchased from different mines is different, but generally, the recovery rate can be improved by about 2% -5%, the improvement range of the recovery rate is not large, but the general profit margin of the ultrafine calcium carbonate industry is only less than 10%, and the improvement range is large in the view of profit margin.

Secondly, in the prior art, the product C is put into a water pool for digestion and then is added with carbon dioxide, the formed calcium carbonate precipitate has large water content, is thick slurry after dehydration, and still has large water content. According to the invention, a small amount of water is added into the product C to form a wet material, and then the wet material is reacted with high-pressure carbon dioxide to directly produce calcium carbonate, so that the obtained calcium carbonate has low water content, and the drying energy consumption is reduced, namely the production cost is reduced.

And thirdly, aiming at the improved process, equipment required by the improved process is developed, and the equipment comprises a digestion tank and a carbonization device. The digestion tank has the advantages that the over-thick area on the flattened product A can be ensured, the complete digestion of the product A is ensured, the structure is simple, and the use is convenient. The carbonization device has the advantages that a, the tank body has high structural strength, high pressure resistance and difficult deformation, so the service life is long; b. the tank body is not easy to slip, more raw materials can be put in at one time, and the production efficiency is higher; c. the thrust bearing is arranged on the tank body, so that the gravity center of the tank body can be automatically adjusted when the tank body is obliquely discharged, the gravity center of the tank body is arranged between the two rolling shafts and is lower, the tank body is ensured not to be tilted on the basis of ensuring a larger inclination angle of the tank body and facilitating more discharging, and the safety is high.

In conclusion, the invention has the advantages of low production cost, higher production efficiency, long service life and high safety.

Drawings

FIG. 1 is a schematic diagram of the system components.

Fig. 2 is a front view of the digestion tank.

Fig. 3 is a left side view of the digestion tank.

Fig. 4 is a front view of the carbonizing apparatus.

Fig. 5 is a left side view of the carbonizing apparatus.

Fig. 6 is a top view of the carbonizing apparatus at a roller.

Fig. 7 is a right side view of fig. 6.

Fig. 8 is a schematic view of the carbonizing apparatus when the cylinder is extended.

The labels in the figures are: 1-jaw crusher, 2-shaft kiln, 3-digestion tank, 4-vibrating screen, 5-stirrer, 6-carbonizing device, 7-dryer, 8-depolymerizer, 9-activator;

300-opening and closing door, 301-water mist spraying mechanism, 302-exhaust mechanism, 303-moving plate, 304-gap, 305-sliding block, 306-sliding rail, 307-handle, 308-window and 309-fan;

600-tank body, 601-air inlet valve, 602-pneumatic rotary joint, 603-feed valve, 604-bottom plate, 605-roller, 606-high frame plate, 607-driven wheel, 608-speed reducing motor, 609-driving wheel, 610-belt, 611-annular groove, 612-rack, 613-tooth, 614-bracket, 615-thrust bearing, 616-frame, 617-oil cylinder, 618-support frame, 619-coincident point and 620-reinforced stirring rod.

Detailed Description

The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.

Examples are given. A system for producing high-recovery-rate ultrafine calcium carbonate is shown in figure 1 and comprises a jaw crusher 1, a vertical kiln 2, a digestion tank 3, a vibrating screen 4, a stirrer 5, a carbonization device 6, a dryer 7, a depolymerizer 8 and an activator 9. Wherein, jaw breaker 1, shaft kiln 2, shale shaker 4, mixer 5, drying-machine 7, depolymerizer 8 and activation machine 9 are prior art, can directly purchase on the market and obtain, and digestion tank 3 and carbonizing apparatus 6 are the new development device.

The digestion tank 3 is a sealed tank body structure, one side of the digestion tank 3 is provided with an opening and closing door 300, a water mist spraying mechanism 301 is arranged in the digestion tank 3, and an exhaust mechanism 302 is arranged on the digestion tank 3. The water mist spraying mechanism 301 is in the prior art and comprises an atomizing nozzle arranged at the top of the fixed digestion tank 3, and the atomizing nozzle is connected with tap water through a water pump. The exhaust mechanism 302 comprises windows 308 arranged on two opposite side walls of the digestion chamber 3, wherein one window 308 is provided with a fan 309, and the wind direction of the fan 309 is aligned with the atomizing nozzle.

The digestion tank 3 is rectangular, a vertical moving plate 303 is arranged in the digestion tank 3, a gap 304 is formed between the moving plate 303 and the bottom surface of the digestion tank 3, sliding blocks 305 are arranged on two sides of the moving plate 303, and the sliding blocks 305 are connected with the inner side wall of the digestion tank 3 through sliding rails 306.

Two upper and lower sliding blocks 305 are arranged on two sides of the moving plate 303, the sliding rails 306 are fixed on the inner side walls of the digestion tank 3 in the width direction, and a handle 307 is arranged on the moving plate 303.

The carbonization device 6 comprises a tank body 600 which is horizontally arranged, both ends of the tank body 600 are hemispherical, one end of the tank body 600 is provided with an air inlet valve 601, the air inlet end of the air inlet valve 601 is provided with a pneumatic rotary joint 602, the other end of the tank body 600 is provided with a feeding valve 603, and the tank body 600 is provided with a rotary driving mechanism and an angle adjusting mechanism.

The rotary driving mechanism comprises a bottom plate 604, two rollers 605 are arranged above the bottom plate 604, the two rollers 605 are located on two sides of the bottom of the tank body 600, high frame plates 606 fixed with the bottom plate 604 are arranged at two ends of each roller 605, each roller 605 is rotatably connected with the high frame plates 606, one end of each roller 605 penetrates through one of the high frame plates 606 and is provided with a driven wheel 607, a speed reducing motor 608 is arranged on the bottom plate 604, a driving wheel 609 is arranged at the output end of the speed reducing motor 608, and the driving wheel 609 is connected with the driven wheel 607 through a belt 610.

The roller 605 is provided with at least two annular grooves 611, the bottom surface of the annular groove 611 is provided with a plurality of teeth 613 distributed circumferentially, the outer circumferential surface of the tank 600 is provided with annular racks 612, the number of the racks 612 is the same as that of the annular grooves 611 on the roller 605, and the racks 612 are meshed with the teeth 613.

The bottom plate 604 is provided with a support 614 positioned on one side of the tank body 600, the support 614 is provided with a thrust bearing 615 connected with the tank body 600, the feeding valve 603 penetrates through an inner hole of the thrust bearing 615, and the support 614 is provided with a through hole penetrated by the feeding valve 603.

The angle adjusting mechanism comprises a frame 616 positioned below the bottom plate 604, one end of the bottom plate 604 close to the feeding valve 603 is hinged with the frame 616, an oil cylinder 617 is arranged on the frame 616, the rear end of the oil cylinder 617 is hinged with the frame 616, and the output end of the oil cylinder 617 is hinged with the bottom plate 604.

A plurality of support frames 618 formed by connecting three connecting rods end to end are arranged in the tank body 600, and the top points of the support frames 618 are fixed with the tank body 600; when viewed along the axial direction of the tank 600, the adjacent support frames 618 have a torsion angle of 60 degrees; seen along the axial direction of the tank body 600, six coincident points 619 are formed between the adjacent support frames 618, six reinforcing stirring rods 620 are arranged between the adjacent support frames 618, and the six reinforcing stirring rods 620 are respectively positioned on the six coincident points 619.

A production process of superfine calcium carbonate with high recovery rate comprises the following steps: with the system as described above, comprising the steps of,

a. the raw material of limestone is crushed into a small block structure by a jaw crusher 1, and then is put into a vertical kiln 2 for calcination, so that calcium carbonate in the raw material is completely changed into calcium oxide, and a product A is obtained. The material is crushed, not crushed, by a jaw crusher in order to avoid that the crushed silica particles in the material, in the "lime cake", become powder and cannot be screened out in the subsequent steps.

b. The opening and closing door 300 is opened, the product A is placed into the digestion tank 3, the moving plate 303 is pulled by the handle 307 to move back and forth, the product A is flatly laid in the digestion tank 3, and the product A is prevented from being excessively thick due to the height of the gap 304. Starting the water mist spraying mechanism 301 to humidify the digestion tank 3, starting the fan 309 to evaporate water mist to make the humidity of air in the digestion tank 3 reach more than 70% of saturated humidity, gradually raising the temperature in the digestion tank 3 along with the reaction of calcium oxide and water vapor in the air, raising the saturated humidity value of the air, and correspondingly improving the spraying speed of the water mist spraying mechanism 301 so that the air contains more water vapor and the digestion speed of the product A is improved; standing the product A for a period of time which is in direct proportion to the laying thickness of the product A, such as 3cm for the laying thickness of the product A, standing for 24 hours, such as 10cm for the laying thickness of the product A, and standing for 70 hours, opening the window 308 after the product A is completely digested into the product B, ventilating for one hour, opening the opening and closing door 300, and taking out the product B. The window 308 can also be used for controlling the temperature in the digestion tank 3, and when the temperature in the digestion tank 3 is too high, the window 308 can be opened to form a gap, so that the heat dissipation is increased.

c. And (3) the product B passes through the vibrating screen 4, because the main component of the product B is calcium hydroxide formed by digestion, the calcium hydroxide is very loose and is similar to a powder structure, and when the product B passes through the vibrating screen 4, the calcium hydroxide is separated from impurity particles (mainly silica stones) under the action of vibration force, so that the calcium hydroxide with high purity, namely the product C is obtained.

d. Adding water into the product C in a stirrer 5 to prepare a wet material, wherein the mass ratio of the product C to the water is 2:1 to 1:1, the wet material is wet but not slurried. The feed valve 603 is opened, the funnel is inserted into the feed valve 603, the wet material is poured into the tank 600, and the feed valve 603 is closed. The pneumatic rotary joint 602 is connected with a carbon dioxide gas source pressurized by the booster pump, the pressure of the carbon dioxide is kept above 4 atmospheric pressures, so that the high-concentration carbon dioxide in the tank body 600 permeates into the wet material, high-concentration carbonic acid is formed in the wet material, the carbonization speed is increased, the high pressure is very important, and the carbonization speed is very slow under normal pressure, so that the application value is almost not existed. And starting the speed reducing motor 608, driving the driving wheel 609 to rotate, driving the driving wheel 609 to drive the two driven wheels 607 to synchronously rotate through the belt 610, driving the rolling shaft 605 to rotate by the driven wheels 607, driving the tank body 600 to rotate by the rolling shaft 605, continuously rolling the product C in the tank body 600, and fully contacting and reacting with carbon dioxide until calcium carbonate, namely the product D, is completely formed after a period of time. When the air inlet valve 601 is closed, the oil cylinder 617 is connected with a hydraulic pump, the hydraulic pump is started to extend the oil cylinder 617, the oil cylinder 617 pushes the bottom plate 604 to rotate, accordingly, the tank body 600 tilts, when the oil cylinder 617 is at the maximum length, the state is shown in fig. 8, the maximum tilting angle of the tank body 600 cannot exceed 75 degrees, the feeding valve 603 is unscrewed, and under the action of high pressure in the tank body 600, a D product is discharged from the feeding valve 603, so that the discharging speed is high.

e. And (5) drying the product D in a dryer 7 to obtain a product E.

f. And E product is depolymerized in a depolymerizer 8 and activated in an activator 9 to obtain a finished product.

Claims

1. A production process of superfine calcium carbonate with high recovery rate is characterized in that: comprises the following steps of (a) preparing a solution,

c. sieving product B with vibrating screen (4) to obtain product C,

d. adding water into product C to obtain wet material, introducing pressurized carbon dioxide into the wet material to obtain product D,

e. drying the product D to obtain a product E,

2. The process for producing ultrafine calcium carbonate with high recovery rate according to claim 1, wherein the process comprises the following steps: in the step b, the humidity of the air in the sealed space is more than 70% of the saturation humidity.

3. The high recovery rate ultrafine calcium carbonate production process according to claim 1, characterized in that: in the step d, the mass ratio of the product C to the water is 2:1 to 1:1.

4. a system for carrying out the production process according to claim 1, 2 or 3, characterized in that: comprises a jaw crusher (1), a vertical kiln (2), a digestion tank (3), a vibrating screen (4), a stirrer (5), a carbonization device (6), a dryer (7), a depolymerizer (8) and an activator (9); one side of the digestion tank (3) is provided with an opening and closing door (300), a water mist spraying mechanism (301) is arranged in the digestion tank (3), and an exhaust mechanism (302) is arranged on the digestion tank (3).

5. The system of claim 4, wherein: the digestion tank (3) is rectangular, a vertical moving plate (303) is arranged in the digestion tank (3), a gap (304) is formed between the moving plate (303) and the bottom surface of the digestion tank (3), sliding blocks (305) are arranged on two sides of the moving plate (303), and the sliding blocks (305) are connected with the inner side wall of the digestion tank (3) through sliding rails (306).

6. The system of claim 5, wherein: two upper and lower sliding blocks (305) are arranged on two sides of the moving plate (303), the sliding rails (306) are fixed on the inner side wall in the width direction of the digestion tank (3), and a handle (307) is arranged on the moving plate (303).

7. The system of claim 4, wherein: carbonizing apparatus (6) is including the jar body (600) of horizontal placement, and the both ends of jar body (600) are the hemisphere, and the one end of the jar body (600) is equipped with air inlet valve (601), and the air inlet end of air inlet valve (601) is equipped with pneumatic rotary joint (602), and the other end of the jar body (600) is equipped with feed valve (603), is equipped with rotary driving mechanism and angle adjusting mechanism on the jar body (600).

8. The system of claim 7, wherein: the rotary driving mechanism comprises a bottom plate (604), two rolling shafts (605) are arranged above the bottom plate (604), the two rolling shafts (605) are located on two sides of the bottom of the tank body (600), high frame plates (606) fixed with the bottom plate (604) are arranged at two ends of each rolling shaft (605), each rolling shaft (605) is rotatably connected with the corresponding high frame plate (606), one end of each rolling shaft (605) penetrates through one high frame plate (606) and is provided with a driven wheel (607), a speed reducing motor (608) is arranged on the bottom plate (604), a driving wheel (609) is arranged at the output end of the speed reducing motor (608), and the driving wheel (609) is connected with the driven wheel (607) through a belt (610).

9. The system of claim 8, wherein: the rolling shaft (605) is provided with at least two annular grooves (611), the bottom surface of each annular groove (611) is provided with a plurality of teeth (613) which are distributed circumferentially, the outer peripheral surface of the tank body (600) is provided with annular racks (612), the number of the racks (612) is the same as that of the annular grooves (611) on the rolling shaft (605), and the racks (612) are meshed with the teeth (613); the feeding device is characterized in that a support (614) located on one side of the tank body (600) is arranged on the bottom plate (604), a thrust bearing (615) connected with the tank body (600) is arranged on the support (614), the feeding valve (603) penetrates through an inner hole of the thrust bearing (615), and a through hole penetrated by the feeding valve (603) is formed in the support (614).

10. The system of claim 7, wherein: the angle adjusting mechanism comprises a machine frame (616) located below the bottom plate (604), one end, close to the feeding valve (603), of the bottom plate (604) is hinged to the machine frame (616), an oil cylinder (617) is arranged on the machine frame (616), the rear end of the oil cylinder (617) is hinged to the machine frame (616), and the output end of the oil cylinder (617) is hinged to the bottom plate (604).