CN112010651A

CN112010651A - Anode material forming and roasting integrated preparation equipment and preparation method

Info

Publication number: CN112010651A
Application number: CN202010933685.0A
Authority: CN
Inventors: 杨林; 张攀; 张东; 舒弋芮; 王烨; 张志业
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2020-09-08
Filing date: 2020-09-08
Publication date: 2020-12-01

Abstract

The invention provides anode material forming and roasting integrated preparation equipment which comprises a power supply circuit, a forming mould and a pressure head, wherein the forming mould comprises an outer mould shell, an inner mould plate is arranged on the inner side of the outer mould shell, a supporting table is arranged at the bottom of the inner mould plate, the lower part of the pressure head is positioned in the inner mould plate, the top of the pressure head is connected with an upper pressing mechanism, the pressure head, the supporting table and the inner mould plate enclose a closed mould cavity, a heating mechanism is arranged between the inner mould plate and the outer mould shell, an inner heat insulation layer is arranged between the heating mechanism and the outer mould shell, and the heating mechanism is connected with. Also provides an integrated preparation method for molding and roasting the anode material. The invention utilizes the heating mechanism to heat the carbon block, can slowly raise the temperature of the carbon block to more than 1000 ℃, reduces the release of small molecular substances of the asphalt, and simultaneously reaches the temperature required by the roasting process, thereby realizing the completion of the molding and the roasting in the same molding die without repeatedly taking out the carbon block and dipping the asphalt, and greatly improving the preparation efficiency of the anode carbon block.

Description

Anode material forming and roasting integrated preparation equipment and preparation method

Technical Field

The invention relates to the technical field of carbon anode plate manufacturing, in particular to anode material forming and roasting integrated preparation equipment and a preparation method.

Background

In recent years, with the increase of the demand of UF6 (uranium hexafluoride) products in China, the use amount of a carbon anode plate in uranium conversion production is greatly increased, and compared with 2014, the increase is 300%. The performance index of the carbon anode plate which is an important material in fluorine gas production directly influences the production capacity and the production cost of the electrolytic fluorine preparation process. The existing method for preparing the anode material is to mold at high temperature and bake a carbon plate by a conventional method to prepare the anode, specifically, the raw material is pressed and molded by a vibration method or a mold pressing method and then put into a baking furnace for baking, then the carbon plate is impregnated by liquid asphalt and then baked, and generally, the qualified carbon anode can be prepared after twice impregnation and three times of baking, which refers to the invention patent application with the application number of 201610642924.0. The manufacturing steps for manufacturing the fluorocarbon sheet are long, because the binder pitch in the raw material contains a large amount of light component volatile matters, about 40% of the pitch is discharged from the carbon sheet during the roasting process. This results in a loss of mass of the carbon plate while forming a large number of open pores. The current process dictates that the bulk density must be increased by an impregnation and re-firing process in order to achieve a higher density carbon plate. This not only increases the carbon plate production cycle, but also increases the energy consumption.

The invention patent application with application number 201010100172.8 discloses a method and a device for preparing a green body of an anode carbon block of a high-density aluminum electrolysis cell, wherein anode paste is prepared, the anode paste is put into a die cavity and is pressed and formed by an upper die core and a lower die core, the paste is heated to 150-250 ℃ during pressing, the pressure is 40-70 MPa, the duration time of the pressure is 30-100 s, and the heating is used for promoting asphalt to melt and achieve the bonding effect. The device utilizes the mold core as a conductor, so that the electric leakage phenomenon is easy to occur, and the safety is poor; the anode paste is electrified to generate heat to serve as a heat source, the resistance of the paste is small, the resistance can be further reduced in the roasting process, short circuit is easy to cause, the temperature rise is slow, and the temperature required by the roasting process is difficult to reach, so that the device and the method can be used for preparing the fluorocarbon plate only by preparing green bodies, and the green bodies can be used for preparing the fluorocarbon plate only by roasting and dipping asphalt for multiple times, and the problems of long manufacturing period and high energy consumption of the carbon plate cannot be solved. In addition, the article "experimental study of hot die pressing for preparing aluminum electrolysis anode" published in the 6 th year 2015 of non-ferrous metal (smelting part) also discloses a similar scheme, and the problem that only green bodies can be prepared and the green bodies cannot be roasted exists.

Disclosure of Invention

The technical problem to be solved by the invention is to provide the anode material forming and roasting integrated preparation equipment and the preparation method, which can shorten the preparation period of the anode carbon plate, improve the efficiency and reduce the energy consumption.

The technical scheme adopted by the invention for solving the technical problems is as follows: the anode material forming and roasting integrated preparation equipment comprises a power circuit, a forming die and a pressure head, wherein the forming die comprises an outer die shell, an inner die plate is arranged on the inner side of the outer die shell, a supporting table is arranged at the bottom of the inner die plate, the lower part of the pressure head is positioned in the inner die plate and is in sliding fit with the inner die plate, the top of the pressure head is connected with a pressing mechanism, the pressure head, the supporting table and the inner die plate are enclosed to form a closed die cavity, a heating mechanism is arranged between the inner die plate and the outer die shell, an inner heat insulation layer is arranged between the heating mechanism and the outer die shell, and the heating mechanism is connected with.

Further, the inner wall of the inner template is provided with a conducting layer, the heating mechanism is a pure resistor, and the pure resistor is in conductive connection with the conducting layer.

Further, the heating mechanism is a superaudio induction device, and the inner heat insulation layer is made of asbestos.

Further, the heating mechanism is a pure resistor.

Further, the inner template is a corundum plate.

Further, a lower pressing mechanism is arranged on the lower surface of the outer formwork.

Further, the lower pressing mechanism and the upper pressing mechanism are both hydraulic devices.

Further, outer heat insulation layers are arranged between the pressure head and the upper pressing mechanism and between the outer die shell and the lower pressing mechanism.

Furthermore, cooling devices are arranged between the pressure head and the upper pressing mechanism and between the outer die shell and the lower pressing mechanism.

The anode material forming and roasting integrated preparation method adopting the anode material forming and roasting integrated preparation equipment is characterized by comprising the following steps of

Preparing raw materials: uniformly mixing the paste and the asphalt to obtain a raw material;

molding: adding the raw materials into a cavity, heating the raw materials to 180-;

roasting: continuously maintaining the pressure on the carbon block, gradually heating the carbon block to 1100-1250 ℃, cooling to normal temperature at the speed of 5-10 ℃/min after roasting is finished, and finally demoulding.

The invention has the beneficial effects that: the invention utilizes the heating mechanism to heat the carbon block, can slowly raise the temperature of the carbon block to more than 1000 ℃ to reach the temperature required by the roasting process, thereby realizing the completion of the molding and the roasting in the same molding die.

Drawings

FIG. 1 is a schematic diagram of a first embodiment of the present invention;

FIG. 2 is a schematic diagram of a second embodiment of the present invention;

FIG. 3 is a schematic diagram of a third embodiment of the present invention;

reference numerals: 1-a power supply circuit; 2, a pressure head; 3-outer mould shell; 4-inner heat insulation layer; 5, an inner template; 6, supporting the table; 7-a heating mechanism; 8, an upper pressing mechanism; 10-a conductive layer; 12-a lower pressing mechanism; 13-outer insulating layer; 14-cooling means.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

Example one

As shown in fig. 1, the anode material forming and baking integrated preparation equipment of the embodiment includes a power circuit 1, a forming mold and a press head 2, the forming mold includes an outer mold shell 3, an inner mold plate 5 is arranged on the inner side of the outer mold shell 3, a support table 6 is arranged at the bottom of the inner mold plate 5, the lower portion of the press head 2 is located in the inner mold plate 5 and is in sliding fit with the inner mold plate 5, an upper pressing mechanism 8 is connected to the top of the press head 2, a closed cavity is defined by the press head 2, the support table 6 and the inner mold plate 5, a heating mechanism 7 is arranged between the inner mold plate 5 and the outer mold shell 3, an inner heat insulation layer 4 is arranged between the heating mechanism 7 and the outer mold shell 3, and the heating mechanism 7 is connected to.

The power supply circuit 1 can provide currents with various sizes to the heating mechanism 7, so that the heating mechanism 7 generates heat, and meanwhile, the heating amount of the heating mechanism 7 can be adjusted by introducing currents with different sizes to the heating mechanism 7, so that the temperature is controlled. The forming die is used for compression forming of the carbon plate, the forming die comprises an outer die shell 3 and an inner die plate 5, the inner die plate 5 is fixedly connected with the outer die shell 3, and because large pressure is applied during compression and the roasting temperature is high, the inner die plate 5 is made of high-temperature-resistant and high-strength materials, preferably corundum plates, and the corundum plates are high in strength, high in heat resistance and good in insulativity. The pressing head 2 and the upper pressing mechanism 8 are used for applying pressure to the raw materials to enable the raw materials to become carbon plates in the cavity. The pressure head 2, brace table 6 and inner formword 5 enclose into inclosed die cavity, this die cavity should have good leakproofness, the volatile composition of pitch under high temperature can not discharge outside the die cavity like this, but the polycyclic aromatic hydrocarbon of polymerization formation macromolecule under high temperature, carbonization becomes pitch coke at last, thereby make pitch whole combine with the carbon plate, guarantee that calcination just once can make the positive pole carbon plate that density satisfies the requirement, can save the pitch material, reduce the gaseous pollutant that produces in the traditional calcination technology by a wide margin, and the production cost is reduced, and more importantly improves production efficiency.

The heating mechanism 7 is used for heating the raw materials, the heating mechanism 7 can be various existing electric heating devices, the heating mechanism 7 of the embodiment is a pure resistor, the inner wall of the inner template 5 is provided with a conducting layer 10, and the pure resistor is in conductive connection with the conducting layer 10. The heating process is as follows: after the raw material is placed in the cavity, the power circuit 1 leads current into the pure resistor, and when the current passes through the pure resistor, the conducting layer 10 and the raw material, the pure resistor, the conducting layer 10 and the raw material generate heat together to heat the raw material.

The inner heat insulation layer 4 plays roles of heat preservation and heat insulation, can slow down heat loss of the heating mechanism 7, improves heat utilization rate, reduces energy consumption and can also prevent the outer mould shell 3 from being damaged due to overhigh temperature. The inner heat insulation layer 4 is made of asbestos and other heat insulation materials.

In order to increase the pressing pressure, the lower surface of the outer mold shell 3 is provided with a lower pressing mechanism 12. Lower pressing mechanism 12 and last pressing mechanism 8 are hydraulic means, like the pneumatic cylinder etc. power is stronger, goes up pressing mechanism 8 and can drive pressure head 2 and reciprocate to add raw and other materials and the drawing of patterns, and can exert lasting, stable pressure to the carbon plate.

Because the roasting temperature is high, in order to prevent the upper pressing mechanism 8 and the lower pressing mechanism 12 from being damaged by high temperature, an outer heat insulation layer 13 is arranged between the pressure head 2 and the upper pressing mechanism 8 and between the outer die shell 3 and the lower pressing mechanism 12. The outer heat insulation layer 13 is made of high temperature resistant heat insulation material such as asbestos. Furthermore, cooling devices 14 are arranged between the ram 2 and the upper pressing mechanism 8 and between the outer mould shell 3 and the lower pressing mechanism 12. The cooling device 14 may be a water cooling device such as a water cooling tank, etc., which is operated to continuously supply and discharge cooling water, thereby absorbing heat and preventing high temperature from being transferred to the upper and lower

pressing mechanisms

8 and 12.

The anode material forming and roasting integrated preparation method comprises the following steps

Preparing raw materials: and uniformly mixing the paste and the asphalt to obtain the raw material. The paste composition may be determined by the conventional techniques. The proportion of the paste and the asphalt is determined according to the density of the anode carbon plate, and the asphalt is ensured to be completely combined with the carbon plate after roasting, so that the anode carbon plate with the density meeting the requirement is obtained.

Molding: adding the raw materials into a cavity, enabling a pressure head 2 to enter the cavity, enabling a power supply circuit 1 to supply current of 20A/min to a pure resistor, enabling the pure resistor, a conducting layer 10 and the raw materials to be heated after being electrified, heating the raw materials to 180-fold, then applying pressure to the raw materials by using the pressure head 2, gradually increasing the pressure of a lower pressing mechanism 12 and an upper pressing mechanism 8 at the rate of 5MPa/min, gradually shrinking the raw materials after being pressed to form a carbon block, stopping pressurizing after the pressure is increased to 30MPa, maintaining the pressure for 30min under the pressure of 30MPa, and forming the carbon plate.

The lowest viscosity of the bitumen at 180-200 ℃ is beneficial for uniform bonding of bitumen to the paste.

Roasting: the pressure on the carbon block is continuously maintained, the power circuit 1 supplies constant current of 10A/min to the pure resistor, the carbon block is gradually heated to 1100-. And the temperature of 1100-1250 c is maintained, the resistance of the carbon plate is gradually decreased during the firing, and thus, when the current is kept constant, the firing is completed by observing the change of the voltage in the power circuit 1 when the voltage is kept stable. Then cooling to normal temperature at the speed of 5-10 ℃/min, removing pressure, and finally demoulding.

Example two

As shown in fig. 2, on the basis of the first embodiment, the present embodiment adopts different heating mechanisms 7 and heating methods, specifically, the heating mechanism 7 is a super audio frequency induction device, and the inner heat insulation layer 4 is made of asbestos. The main part of the ultrasonic induction device is a high-frequency induction coil, after current is introduced into the high-frequency induction coil, a strong magnetic field with the polarity changing instantly is generated in the high-frequency induction coil, a conductor to be heated is placed in the magnetic field, and the conductor can generate induced current so as to generate heat. In this embodiment, the high frequency induction coil is disposed around the inner mold plate 5, and after the raw material is added into the cavity, the high frequency induction coil is energized to generate an induced current in the raw material, thereby heating the raw material.

Molding: adding the raw materials into a cavity, enabling a pressure head 2 to enter the cavity, enabling a power supply circuit 1 to supply current of 10A/min to a supersonic frequency induction device, generating induction current in the raw materials, heating the raw materials to 180-.

Roasting: and continuously maintaining the pressure on the carbon block, introducing a constant current of 5A/min into the pure resistor by the power circuit 1, slowly heating the carbon block to 1100-1250 ℃, so that the volatile components of the asphalt can be released slowly as much as possible, and gradually reducing the resistance of the carbon plate in the roasting process, so that when the current is kept constant, the roasting is finished by observing the change of the voltage in the power circuit 1 and when the voltage is kept stable. Then cooling to normal temperature at the speed of 5-10 ℃/min, removing pressure, and finally demoulding.

EXAMPLE III

As shown in figure 3 of the drawings,

on the basis of the first embodiment, different heating mechanisms 7 and heating methods are adopted in the present embodiment, specifically, the heating mechanism 7 is a pure resistor, and the pure resistor is separated from the raw material by the internal template 5 made of corundum. The heat generated by the pure resistor after being energized is transferred to the raw material through the inner die plate 5, thereby raising the temperature of the raw material.

Molding: adding raw materials into a cavity, enabling a pressure head 2 to enter the cavity, enabling a power supply circuit 1 to supply 5-8A/min of current to a pure resistor, heating the pure resistor after electrifying, transferring heat to the raw materials through an inner template 5, heating the raw materials to 180 degrees, applying pressure to the raw materials by using the pressure head 2, gradually increasing the pressure of a lower pressing mechanism 12 and an upper pressing mechanism 8 at the rate of 5MPa/min, gradually shrinking the raw materials after being pressed to form a carbon block, stopping pressurizing after the pressure is increased to 30MPa, maintaining the pressure for 30min under the pressure of 30MPa, and forming the carbon plate.

Roasting: and continuously maintaining the pressure on the carbon block, introducing a constant current of 2-4A/min into the pure resistor by the power circuit 1, slowly heating the carbon block to 1100-1250 ℃, releasing the volatile components of the asphalt as slowly as possible, and carrying out heat preservation roasting for 10-15h at the temperature of 1100-1250 ℃, thus finishing roasting. Then cooling to normal temperature at the speed of 5-10 ℃/min, removing pressure, and finally demoulding.

In the preparation process of the invention, the pitch deposition coking process can be divided into four stages: formation of tiny carbon particles, growth of carbon particles, deposition of pyrolytic carbon from carbon particles, and aggregate growth of carbon particles. Asphalt is volatilized continuously at high temperature, so that not only are pores between aggregates caused, but also the aggregation and growth of the asphalt are influenced. The volatilization of low molecular weight aromatic compounds in the asphalt compound can be prevented by continuously applying pressure to the carbon plate, and the polymerization reaction is facilitated, and a series of complex reactions such as dehydrogenation, C-C bond breakage, decomposition, polymerization, condensation and the like are carried out in the asphalt carbonization process. The presence of pressure prevents their volatilization and promotes their polymerization to form large molecular weight fused ring aromatics, which are eventually carbonized to pitch coke, as the C-C cleavage produces new lower molecular weight molecules. The pressurized firing of the carbon block reduces the contact porosity between the particles and increases the bulk density of the carbon plate.

In conclusion, the invention can complete the press forming and the roasting in one step, greatly improves the production efficiency and reduces the production cost.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An anode material forming and roasting integrated preparation device comprises a power circuit (1), a forming die and a pressure head (2), the forming die comprises an outer die shell (3), an inner die plate (5) is arranged on the inner side of the outer die shell (3), a support table (6) is arranged at the bottom of the inner die plate (5), the lower part of the pressure head (2) is positioned in the inner template (5) and is in sliding fit with the inner template (5), the top of the pressure head (2) is connected with an upper pressing mechanism (8), it is characterized in that the pressure head (2), the support platform (6) and the inner template (5) enclose a closed cavity, a heating mechanism (7) is arranged between the inner template (5) and the outer mould shell (3), an inner heat insulation layer (4) is arranged between the heating mechanism (7) and the outer formwork (3), and the heating mechanism (7) is connected with the power circuit (1).

2. The anode material forming and roasting integrated preparation equipment as claimed in claim 1, wherein: the inner wall of the inner template (5) is provided with a conducting layer (10), the heating mechanism (7) is a pure resistor, and the pure resistor is in conductive connection with the conducting layer (10).

3. The anode material forming and roasting integrated preparation equipment as claimed in claim 1, wherein: the heating mechanism (7) is a superaudio induction device, and the inner heat insulation layer (4) is made of asbestos.

4. The anode material forming and roasting integrated preparation equipment as claimed in claim 1, wherein: the heating mechanism (7) is a pure resistor.

5. The anode material forming and baking integrated manufacturing apparatus as claimed in any one of claims 1 to 4, wherein: the inner template (5) is a corundum plate.

6. The anode material forming and baking integrated manufacturing apparatus as claimed in any one of claims 1 to 4, wherein: the lower surface of the outer mould shell (3) is provided with a lower pressing mechanism (12).

7. The anode material molding and baking integrated preparation equipment as claimed in claim 6, wherein: the lower pressing mechanism (12) and the upper pressing mechanism (8) are both hydraulic devices.

8. The anode material molding and baking integrated preparation equipment as claimed in claim 6, wherein: and outer heat insulation layers (13) are arranged between the pressure head (2) and the upper pressing mechanism (8) and between the outer mould shell (3) and the lower pressing mechanism (12).

9. The anode material molding and baking integrated preparation equipment as claimed in claim 6, wherein: and cooling devices (14) are arranged between the pressure head (2) and the upper pressing mechanism (8) and between the outer mould shell (3) and the lower pressing mechanism (12).

10. The integrated preparation method of anode material molding and baking by using the integrated preparation equipment of anode material molding and baking of claim 1, characterized by comprising