CN115338043A

CN115338043A - High-efficiency centrifugal dehydration process and dehydrator for superfine calcium carbonate slurry

Info

Publication number: CN115338043A
Application number: CN202211072035.7A
Authority: CN
Inventors: 汪志伟; 张清华; 项舜; 庄涛
Original assignee: Hangzhou Zhenghe Nano Technology Co ltd
Current assignee: Hangzhou Zhenghe Nano Technology Co ltd
Priority date: 2022-09-01
Filing date: 2022-09-01
Publication date: 2022-11-15
Anticipated expiration: 2042-09-01
Also published as: CN115338043B

Abstract

The invention discloses a high-efficiency centrifugal dehydration process and a dehydrator for superfine calcium carbonate slurry, which utilize centrifugal force to realize solid-liquid separation of the slurry in the radial direction, form a solid layer (18) with calcium carbonate as the main component at the outer side and a liquid layer (19) with liquid water as the main component at the inner side, provide power advancing in one direction for the solid layer (18), provide power advancing in the opposite direction for the liquid layer (19), separate the solid layer (18) from the liquid layer (19), and realize dehydration; the power for advancing the solid layer (18) and the power for realizing solid-liquid separation of the slurry are generated by the same driving mechanism. The invention has the advantages of high dehydration efficiency and simple structure.

Description

High-efficiency centrifugal dehydration process and dehydrator for superfine calcium carbonate slurry

Technical Field

The invention belongs to the field of superfine calcium carbonate production equipment, and particularly relates to a high-efficiency centrifugal dehydration process for superfine calcium carbonate slurry and a dehydrator.

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, namely calcium carbonate slurry, dehydrating, drying, depolymerizing and activating the calcium carbonate precipitate to obtain a finished product.

The centrifugal hydroextractor is adopted in current calcium carbonate precipitation dehydration, the structure of hydroextractor includes the cylinder, the inside of cylinder is equipped with hollow pivot, the outside of pivot is equipped with the spiral plate, the inner peripheral surface of spiral plate and the outer peripheral face snap-on of pivot, all be equipped with actuating mechanism in cylinder and the pivot, the turning to of cylinder and pivot is opposite, calcium carbonate precipitation lets in from the one end of pivot, discharge from the middle part of pivot, solid-liquid separation under the huge centrifugal force that produces at cylinder and pivot rotation in opposite directions, solid part promotes and removes along the cylinder inner wall through the spiral plate, discharge from the one end of cylinder, water then the middle part of well cylinder removes, discharge from the other end of cylinder. More specifically, the detailed website is https:// www.chem17.com/tech _ news/detail/2444137.Html. The solid calcium carbonate can be pushed out by the spiral plate, and simultaneously, part of water can be pushed out, so that the water content of the calcium carbonate obtained by dehydration is still high, about 40%, the dehydration efficiency is low, the energy consumption required by subsequent drying is large, and the production cost of the finished product is high. In addition, the existing dehydrator adopts two sets of driving mechanisms, so that the structure is complex, the equipment is easy to break down, and the cost is high.

Therefore, the existing dehydrator has the defects of low dehydration efficiency and complex structure.

Disclosure of Invention

The invention aims to provide a high-efficiency centrifugal dehydration process and a dehydrator for ultrafine calcium carbonate slurry. The invention has the advantages of high dehydration efficiency and simple structure.

The technical scheme of the invention is as follows: a high-efficiency centrifugal dewatering process for superfine calcium carbonate slurry features that the solid-liquid separation of slurry in radial direction is realized by centrifugal force to form a solid layer whose main component is calcium carbonate and a liquid layer whose main component is liquid water, and the power for moving forward in one direction and the power for moving forward in another direction are supplied to the liquid layer to separate the solid layer from the liquid layer for dewatering.

In the high-efficiency centrifugal dehydration process for the superfine calcium carbonate slurry, the power for advancing the solid layer and the power for realizing solid-liquid separation of the slurry are generated by the same driving mechanism.

The utility model provides a high-efficient superfine calcium carbonate thick liquids centrifugal dehydrator, including sealed shell, the outside of shell is equipped with the motor, the output of motor is equipped with first action wheel and second action wheel, the inboard of shell is equipped with the confined cylinder, the one end of cylinder is equipped with first delivery port, the other end of cylinder is equipped with first discharge gate, be equipped with the pivot in the cylinder, the outside of pivot is equipped with spiral helicine first gusset, the laminating of first gusset and the inner wall of cylinder, the cylinder is all stretched out at the both ends of pivot, the one end of pivot is equipped with the runner, the export of runner is located the middle part of pivot, the other end and the shell of pivot rotate and are connected, the outside of the pivot other end is equipped with first follower, first action wheel is connected through first belt to first follower, one side of first follower is equipped with the axle sleeve fixed with the cylinder, the axle sleeve rotates with the shell to be connected, be equipped with the second follower on the axle sleeve, the second follower passes through the second belt and connects the second action wheel.

In the efficient superfine calcium carbonate slurry centrifugal dehydrator, the first rib plates are fixed with the rotating shaft through the connecting rods, the inner sides of the first rib plates are provided with the second rib plates which are spiral, the second rib plates are fixed with the rotating shaft, and the rotating directions of the second rib plates and the first rib plates are opposite.

In the efficient superfine calcium carbonate slurry centrifugal dehydrator, the slurry is subjected to solid-liquid separation in the roller to form a solid layer, and the front part of the first rib plate is positioned in the solid layer.

In the efficient superfine calcium carbonate slurry centrifugal dehydrator, the slurry is subjected to solid-liquid separation in the roller to form a liquid layer, and the second rib plate is positioned inside the liquid layer.

In the efficient superfine calcium carbonate slurry centrifugal dehydrator, a rotary joint communicated with a flow channel is arranged on the rotating shaft, and a feeding pipe penetrating through the shell is arranged on the rotary joint; the bottom of shell is equipped with second delivery port and second discharge gate, and the second delivery port is located the below of first delivery port, and the second discharge gate is located the below of first discharge gate, is equipped with the baffle on the interior bottom surface of shell, and the baffle is located between second delivery port and the second discharge gate.

In the aforesaid high-efficient superfine calcium carbonate thick liquids centrifugal dehydrator, the one end of pivot is equipped with first bearing, and first bearing passes through first leg joint shell, the other end of pivot passes through the second bearing and connects the shell, the one end of cylinder is equipped with the third bearing with first leg joint, and the other end of cylinder is equipped with the fourth bearing, and the fourth bearing passes through the second leg joint shell.

In the efficient superfine calcium carbonate slurry centrifugal dehydrator, the roller comprises a separation section, a pressing section and a homogenizing section, the separation section and the homogenizing section are both in a circular tube shape, the diameter of the separation section is larger than that of the homogenizing section, and the pressing section is in a conical tube shape; the first water outlet is positioned on the end face of the roller close to the separation section, and the first discharge hole is positioned on the homogenizing section.

In the efficient superfine calcium carbonate slurry centrifugal dehydrator, one end of the first rib plate is close to the first water outlet, the other end of the first rib plate extends into the homogenizing section, and an inner hole of the first rib plate in the homogenizing section is attached to the rotating shaft; one end of the second rib plate is close to the outlet of the flow passage, and the other end of the second rib plate is positioned in the pressing section.

Compared with the prior art, the invention adopts a motor to drive the roller and the rotating shaft to rotate simultaneously, and different rotating speeds exist between the roller and the rotating shaft by controlling the diameters of the driving wheel and the driven wheel, thereby smoothly ensuring the calcium carbonate after dehydration and the axial reverse movement of the dehydrated water, realizing solid-liquid separation, having simpler structure and being difficult to cause equipment failure. Be equipped with two heliciform gussets of size in the pivot, the gusset in the outside is used for promoting calcium carbonate and discharges, because the front portion of the gusset in the outside is located solid-state layer, and the outside gusset only pushes the calcium carbonate in solid-state layer and squeezes in squeezing the section, has reduced the water content of calcium carbonate before squeezing, and then reducible finished product moisture content. Because the spiral directions of the two rib plates are opposite, the feeding direction of the outer side rib plate is opposite to that of the inner side rib plate, and the inner side rib plate is arranged at the inner side of the squeezing section, namely close to the side of the rotating shaft, a low-pressure area is formed, so that the moisture in the squeezing section is promoted to be discharged, the calcium carbonate in the squeezing section is further dried, the moisture content of a finished product is reduced, the moisture content can be reduced to 31.7%, the dehydration efficiency is high, the subsequent required drying energy consumption is reduced, and the production cost is reduced. Therefore, the invention has the advantages of high dehydration efficiency and simple structure.

Drawings

Fig. 1 is a front view of a centrifugal dehydrator.

Fig. 2 is a schematic cross-sectional view of a rotating shaft.

The labels in the figures are: 1-a shell, 2-a motor, 3-a first driving wheel, 4-a second driving wheel, 5-a roller, 6-a first water outlet, 7-a first discharge port, 8-a rotating shaft, 9-a first rib plate, 10-a flow channel, 11-a first driven wheel, 12-a first belt, 13-a shaft sleeve, 14-a second driven wheel, 15-a second belt, 16-a connecting rod, 17-a second rib plate, 18-a solid layer, 19-a liquid layer, 20-a rotating joint, 21-a feed pipe, 22-a second water outlet, 23-a second discharge port, 24-a partition plate, 25-a first bearing, 26-a first support, 27-a second bearing, 28-a third bearing, 29-a fourth bearing, 30-a second support, 31-a separation section, 32-a squeezing section and 33-a homogenization section.

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 high-efficiency centrifugal dewatering process for superfine calcium carbonate slurry features that the solid-liquid separation of slurry in radial direction is realized by centrifugal force to form a solid layer 18 whose main component is calcium carbonate and a liquid layer 19 whose main component is liquid water, and the power for moving forward in one direction is supplied to the solid layer 18 and the power for moving forward in another direction is supplied to the liquid layer 19 to separate the solid layer 18 from the liquid layer 19 for dewatering.

The power for advancing the solid layer 18 and the power for realizing solid-liquid separation of the slurry are generated by the same driving mechanism.

The utility model provides a high-efficient superfine calcium carbonate thick liquids centrifugal dehydrator, as shown in figure 1, including sealed shell 1, the outside of shell 1 is equipped with motor 2, the output of motor 2 is equipped with first action wheel 3 and second action wheel 4, the inboard of shell 1 is equipped with confined cylinder 5, the one end of cylinder 5 is equipped with first delivery port 6, the other end of cylinder 5 is equipped with first discharge gate 7, be equipped with pivot 8 in the cylinder 5, the outside of pivot 8 is equipped with spiral helicine first gusset 9, first gusset 9 is laminated with the inner wall of cylinder 5, cylinder 5 is all stretched out at the both ends of pivot 8, the one end of pivot 8 is equipped with runner 10, the export of runner 10 is located the middle part of pivot 8, the other end of pivot 8 is connected with shell 1 rotation, the outside of the pivot 8 other end is equipped with first follower 11, first follower 11 connects first action wheel 3 through first belt 12, one side of first follower 11 is equipped with the axle sleeve 13 fixed with cylinder 5, axle sleeve 13 rotates with shell 1 to be connected, be equipped with second follower 14 on the axle sleeve 13, second follower 14 passes through second action wheel 15 and connects second action wheel 4.

The first rib plates 9 are fixed with the rotating shaft 8 through a plurality of connecting rods 16, spiral second rib plates 17 are arranged on the inner sides of the first rib plates 9, the second rib plates 17 are fixed with the rotating shaft 8, and the rotating directions of the second rib plates 17 and the first rib plates 9 are opposite. The feeding area of any section of the second rib plate 17 is smaller than that of any section of the first rib plate 9.

The slurry is subjected to solid-liquid separation in the roller 5 to form a solid layer 18, and the front part of the first rib plate 9 is positioned inside the solid layer 18. The front part of the first rib plate 9 is the first rib plate 9 positioned between the outlet of the flow channel 10 and the first discharge hole 7.

The slurry is subjected to solid-liquid separation in the roller 5 to form a liquid layer 19, and the second rib plates 17 are positioned in the liquid layer 19.

The rotating shaft 8 is provided with a rotating joint 20 communicated with the flow passage 10, and the rotating joint 20 is provided with a feeding pipe 21 penetrating through the shell 1; the bottom of shell 1 is equipped with second delivery port 22 and second discharge gate 23, and second delivery port 22 is located the below of first delivery port 6, and second discharge gate 23 is located the below of first discharge gate 7, is equipped with baffle 24 on the interior bottom surface of shell 1, and baffle 24 is located between second delivery port 22 and the second discharge gate 23.

One end of the rotating shaft 8 is provided with a first bearing 25, the first bearing 25 is connected with the shell 1 through a first support 26, the other end of the rotating shaft 8 is connected with the shell 1 through a second bearing 27, one end of the roller 5 is provided with a third bearing 28 connected with the first support 26, the other end of the roller 5 is provided with a fourth bearing 29, and the fourth bearing 29 is connected with the shell 1 through a second support 30.

The roller 5 comprises a separation section 31, a squeezing section 32 and a homogenizing section 33, the separation section 31 and the homogenizing section 33 are both in a circular tube shape, the diameter of the separation section 31 is larger than that of the homogenizing section 33, and the squeezing section 32 is in a conical tube shape; the first water outlet 6 is positioned on the end surface of the roller 5 close to the separation section 31, and the first discharge hole 7 is positioned on the homogenization section 33.

One end of the first rib plate 9 is close to the first water outlet 6, the other end of the first rib plate 9 extends into the homogeneous section 33, and an inner hole of the first rib plate 9 in the homogeneous section 33 is attached to the rotating shaft 8; one end of the second rib plate 17 is close to the outlet of the runner 10, and the other end of the second rib plate 17 is positioned in the press section 32. The second rib plates 17 are far away from the first water outlet 6, so that slurry coming out of the flow channel 10 is prevented from being completely sent out of the first water outlet 6 without being separated by centrifugal force, the low content of calcium carbonate in discharged water is ensured, and the utilization rate is improved.

The speed ratio between the first driving wheel 3 and the first driven wheel 11 is A, the speed ratio between the second driving wheel 4 and the second driven wheel 14 is B, A is not equal to B, and therefore a rotation speed difference exists between the roller 5 and the rotating shaft 8. Preferably, the rotation speed of the rotating shaft 8 is 15 rpm faster than the rotation speed of the drum 5.

The water content of the dehydrated product obtained at the rotation speed of the rotary shaft 8 was as shown in Table 1 below at a rotation speed of 1800 rpm of the rotary drum 5.

TABLE 1

As can be seen from table 1, the greater the speed difference between the shaft 8 and the drum 5, the higher the moisture content of the dehydrated product, which may be the greater the radial disturbance of the solid layer 18 by the first web 9, resulting in a portion of the calcium carbonate leaving the solid layer 18 and a corresponding portion of the water in the liquid layer 19 replenishing into the solid layer 18. When the speed difference is less than 15 r/min, the water content of the dehydrated product is not reduced any more, but the dehydrated product is continuously reduced, the discharging speed of the dehydrated product is too slow until the dehydrated product is not discharged, when the rotating speed of the rotating shaft 8 is 15 r/min faster than that of the roller 5, the dehydrated product with low water content can be obtained, and the dehydrated product can be discharged smoothly.

The working principle is as follows: the feed pipe 21 is connected to a water pump which pumps the slurry into the rotating shaft 8 and into the drum 5 through the flow channel 10. The motor 2 drives the first driving wheel 3 and the second driving wheel 4 to synchronously rotate, the first driving wheel 3 drives the first driven wheel 11 to rotate through the first belt 12, the first driven wheel 11 drives the rotating shaft 8 to rotate, the second driving wheel 4 drives the second driven wheel 14 to rotate through the second belt 15, the second driven wheel 14 drives the roller 5 to rotate through the shaft sleeve 13, the roller 5 drives the pulp to rotate at a high speed, because the density of water and the density of calcium carbonate are different, the water moves inwards to be close to the rotating shaft 8 to form a liquid layer 19, and the calcium carbonate moves outwards to be close to the roller 5 to form a solid layer. The rotating shaft 8 drives the first rib plate 9 to rotate through the connecting rod 16, because of the rotation speed difference between the rotating shaft 8 and the roller 5, the first rib plate 9 and the roller 5 rotate relatively, the first rib plate 9 pushes the solid layer 18 to move towards the first discharge port 7, after the solid layer enters the squeezing section 32, the passing area is reduced, the pressure is generated inside the calcium carbonate, more water is extruded, the extruded water moves leftwards, the solid layer is discharged from the roller 5 through the first discharge port 6, the shell 1 is discharged from the second discharge port 22, the calcium carbonate enters the homogenizing section and then is further extruded, the water content is lower, then the solid layer is discharged from the roller 5 through the first discharge port 7, the shell 1 is discharged from the second discharge port 23, and a dehydration product is obtained.

The water content of the dehydrated product is 31.7 percent through inspection.

Comparative example 1. On the basis of the embodiment 1, the second rib plate 17 and the connecting rod 16 are eliminated, and the inner hole of the first rib plate 9 is reduced to be directly fixed on the rotating shaft 8, which is the structure of the rotating shaft and the spiral plate fixed on the rotating shaft in the prior art. The water content of the dehydrated product is 38.5 percent through inspection.

Comparative example 2. The homogenization section 33 is eliminated on the basis of example 1. The water content of the dehydrated product is 34.1 percent through inspection. The homogeneous section 33 is mainly used for keeping the pressure in the squeezing section 32 constant, avoids being influenced by the throwing force of the first discharge port 7, and the length of the homogeneous section 33 is kept above 20cm, so that the squeezing stability of the water in the squeezing section 32 is kept, and the water content of a dehydrated product is reduced. The length of the homogenizing section 33 is preferably not more than 30cm, and the length of the homogenizing section 33 exceeding 30cm does not produce a better positive effect, and increases the removal resistance and the energy consumption.

Claims

1. A high-efficiency centrifugal dehydration process for superfine calcium carbonate slurry is characterized in that: the slurry is subjected to solid-liquid separation in the radial direction by utilizing centrifugal force, a solid layer (18) with calcium carbonate as the main component at the outer side and a liquid layer (19) with liquid water as the main component at the inner side are formed, power advancing in one direction is provided for the solid layer (18), power advancing in the opposite direction is provided for the liquid layer (19), the solid layer (18) and the liquid layer (19) are separated, and dehydration is realized.

2. The high-efficiency centrifugal dewatering process for ultrafine calcium carbonate slurry according to claim 1, characterized in that: the power for advancing the solid layer (18) and the power for realizing solid-liquid separation of the slurry are generated by the same driving mechanism.

3. The utility model provides a high-efficient superfine calcium carbonate thick liquids centrifugal dehydrator which characterized in that: including sealed shell (1), the outside of shell (1) is equipped with motor (2), the output of motor (2) is equipped with first action wheel (3) and second action wheel (4), the inboard of shell (1) is equipped with confined cylinder (5), the one end of cylinder (5) is equipped with first delivery port (6), the other end of cylinder (5) is equipped with first discharge gate (7), be equipped with pivot (8) in cylinder (5), the outside of pivot (8) is equipped with spiral helicine first gusset (9), the inner wall laminating of first gusset (9) and cylinder (5), cylinder (5) all stretch out at the both ends of pivot (8), the one end of pivot (8) is equipped with runner (10), the export of runner (10) is located the middle part of pivot (8), the other end of pivot (8) rotates with shell (1) to be connected, the outside of pivot (8) the other end is equipped with first follower (11), first follower (11) are connected first action wheel (3) through first belt (12), one side of first follower (11) is equipped with the fixed axle sleeve (5) and second action wheel (13) are connected through second follower (13), second follower (13) and second action wheel (13) are connected on second follower (13).

4. The high-efficiency ultrafine calcium carbonate slurry centrifugal dehydrator according to claim 3, wherein: the first rib plates (9) are fixed with the rotating shaft (8) through a plurality of connecting rods (16), spiral second rib plates (17) are arranged on the inner sides of the first rib plates (9), the second rib plates (17) are fixed with the rotating shaft (8), and the rotating directions of the second rib plates (17) and the first rib plates (9) are opposite.

5. The high-efficiency ultrafine calcium carbonate slurry centrifugal dehydrator according to claim 4, wherein: the slurry is subjected to solid-liquid separation in the roller (5) to form a solid layer (18), and the front part of the first rib plate (9) is positioned in the solid layer (18).

6. The high-efficiency ultrafine calcium carbonate slurry centrifugal dehydrator according to claim 4, wherein: the slurry is subjected to solid-liquid separation in the roller (5) to form a liquid layer (19), and the second rib plates (17) are positioned in the liquid layer (19).

7. The high-efficiency ultrafine calcium carbonate slurry centrifugal dehydrator according to claim 3, wherein: a rotary joint (20) communicated with the flow channel (10) is arranged on the rotating shaft (8), and a feeding pipe (21) penetrating through the shell (1) is arranged on the rotary joint (20); the bottom of shell (1) is equipped with second delivery port (22) and second discharge gate (23), and second delivery port (22) are located the below of first delivery port (6), and second discharge gate (23) are located the below of first discharge gate (7), are equipped with baffle (24) on the interior bottom surface of shell (1), and baffle (24) are located between second delivery port (22) and second discharge gate (23).

8. The high-efficiency ultrafine calcium carbonate slurry centrifugal dehydrator according to claim 3, wherein: the one end of pivot (8) is equipped with first bearing (25), and shell (1) is connected through first support (26) in first bearing (25), shell (1) is connected through second bearing (27) to the other end of pivot (8), the one end of cylinder (5) is equipped with third bearing (28) of being connected with first support (26), and the other end of cylinder (5) is equipped with fourth bearing (29), and shell (1) is connected through second support (30) in fourth bearing (29).

9. The high-efficiency ultrafine calcium carbonate slurry centrifugal dehydrator according to claim 5, wherein: the roller (5) comprises a separation section (31), a squeezing section (32) and a homogenizing section (33), the separation section (31) and the homogenizing section (33) are both in a circular tube shape, the diameter of the separation section (31) is larger than that of the homogenizing section (33), and the squeezing section (32) is in a conical tube shape; the first water outlet (6) is positioned on the end face, close to the separation section (31), of the roller (5), and the first discharge hole (7) is positioned on the homogenization section (33).

10. The high-efficiency centrifugal dehydrator for ultrafine calcium carbonate slurry as claimed in claim 9, wherein: one end of the first rib plate (9) is close to the first water outlet (6), the other end of the first rib plate (9) extends into the homogenizing section (33), and an inner hole of the first rib plate (9) in the homogenizing section (33) is attached to the rotating shaft (8); one end of the second rib plate (17) is close to the outlet of the flow channel (10), and the other end of the second rib plate (17) is positioned in the pressing section (32).