CN107557819A - A metal calcium electrolytic cell using bipolar electrodes - Google Patents

Abstract

A metal calcium electrolytic cell adopting bipolar electrodes includes a bipolar electrode system, an electrolyte surface sealing system, a lining insulation system, and an upper gas collection system. The electrolyte surface sealing system is equipped with chlorine gas escape and discharge port, separator and metal calcium suction port, and the lining insulation system includes insulation system, insulation system and tank shell support system. One side of each bipolar electrode is used as an anode, and the other side is used as a cathode. The combination of each pair of electrodes can be regarded as an electrolytic cell, and they are connected in series one by one. During the working process, the current flows from one end of the cell to the first anode. , and then flows into the cathode surface of the next electrode through the electrolyte, and finally reaches the last cathode at the end of the tank. Therefore, the electrolysis can operate at relatively low cell current and relatively high cell voltage, which makes current transmission easier, and its pole distance can be controlled within a small range. The entire electrolytic cell is very compact and has a very high output rate.

Description

A metal calcium electrolytic cell using bipolar electrodes

technical field

The invention belongs to the technical field of calcium electrolysis, and in particular relates to a metal calcium electrolytic cell using bipolar electrodes.

technical background

The industrial production of high-purity calcium metal mainly adopts the molten salt electrolysis method of calcium chloride, which is divided into contact cathode method and liquid cathode method according to the different electrodes used. The contact cathode method produces calcium-rich copper-calcium alloy, and then evaporates to obtain metallic calcium, while the contact cathode method directly obtains metallic calcium through electrolysis, which is the most direct method for calcium production. The traditional contact cathode method was first proposed by W. Rathenau in 1904. This method uses iron rods as cathodes and graphite carbon blocks as anodes for electrolytic production in an electrolyte composed of CaCl ₂ and CaF ₂ . Since the density of the electrolyte is much greater than that of molten metal The density of calcium, so the electrolytic cell is designed so that the cathode is close to the upper part of the cell and the anode is at the lower part of the cell. During the electrolysis process, calcium is precipitated on the cathode through an electrochemical reaction, and chlorine gas is precipitated on the anode. Since the density of calcium is lower than that of molten calcium chloride, Instead, it floats on the surface of the electrolyte and condenses on the cathode when in contact with the steel cathode. As the electrolysis progresses, the cathode continues to rise accordingly, and the calcium forms a carrot-shaped stick at the bottom of the cathode. As electrolysis begins, the electrolyte below the cathode boils, producing calcium beads that condense as soon as they touch the cold surface of the cathode and stick to the anode. As the cathode is lifted, new calcium beads are regenerated below the cathode.

This method is the most direct method for producing high-purity calcium metal, but in order to make the electrolysis run normally, a high cathode current density (40-60A/cm ² ) and a high cell voltage (20-30V) must be used. There are industrial methods for electrolytic production of calcium metal, and the cell type is often small. Generally, an iron rod is used as the cathode, resulting in a large current in the electrolytic cell, but the actual output is small. high reason. At the same time, if an iron rod is used as the cathode, its temperature has a great influence on the electrolysis process, and the actual operation often relies on manual methods such as primitive manual visual observation, resulting in very low labor productivity for calcium chloride electrolysis.

Therefore, in order to solve the problems of high energy consumption, low output and low labor productivity in the production of calcium metal by the traditional contact method, it is necessary to design a new type of electrolytic cell, that is, firstly, the structure of the electrode must be innovated, and then the escape of chlorine gas, The precipitation method of metal calcium is innovated, thereby changing the entire production process and realizing continuous, low energy consumption and high-efficiency production of metal calcium electrolysis.

Contents of the invention

The purpose of the present invention is to propose a metal calcium electrolytic cell using bipolar electrodes. Using this electrolytic cell, the production process of the existing contact cathode electrolytic calcium can be improved, and the calcium obtained by electrolysis can be collected in a specially designed collection area, thereby Realize efficient and large-scale production of calcium electrolysis, eliminate many disadvantages of contact method calcium electrolysis, and improve its technical level.

In order to solve the above-mentioned technical problems, the present invention provides a bipolar electrode system, an electrolyte surface sealing system, and a lining insulation system provided in the tank shell. The lining insulation system includes an insulating layer and is wrapped outside the insulating layer. The insulating layer encloses an electrolysis area with an upper opening, and the electrolysis area is divided into multiple separate work areas by adjacent bipolar electrode systems, and the bipolar electrode systems in each work area Contrary to the electrodes on the working surface, the upper opening of each working area is sealed by the electrolyte surface sealing system, and the electrolyte surface sealing system is provided with a chlorine gas escape and discharge port and a metal calcium suction port.

The bipolar electrode system includes a bipolar electrode, and the bipolar electrode is provided with a mesh conductive skeleton. One side of each bipolar electrode is used as an anode, and the other side is used as a cathode. The combination of each pair of bipolar electrodes can be regarded as an electrolytic cell, and each of them is connected in series. During the working process, the current flows from one end of the cell to the second. An anode, then flows through the electrolyte into the cathode side of the next electrode, and finally reaches the last cathode at the end of the cell. Therefore, the electrolysis can operate at relatively low cell current and relatively high cell voltage, which makes current transmission easier, and its pole distance can be controlled within a small range. The entire electrolytic cell is very compact and has a very high output rate.

The mesh conductive skeleton includes a main conductive rod and a plurality of conductive groups distributed vertically and equidistantly on the main conductive rod. A plurality of conductive rods on the connecting bus bar and a plurality of branch conductive wires installed on the conductive rod, the plurality of connecting bus bars are connected through the main conductive rod, and each connecting bus bar is respectively installed on both sides of the main conductive rod. A conductive rod, branched conductive wires are installed on the conductive rod, the branched conductive wires form a herringbone shape on the conductive rod, and the conductive rod and the branched conductive wires form a tree-like conductive structure.

The bipolar electrode is composed of a rectangular parallelepiped graphite carbon block with a thickness of 50-100 mm, and the length and width match the size of the electrolytic cell.

An upper gas collection system for sealing the upper opening of the electrolysis zone is arranged above the tank shell.

The chlorine gas escape and feed opening is a circular hole with a diameter of 30-150mm, and the chlorine gas escape and feed opening is close to the anode side of the bipolar electrode system.

The metal calcium suction port is close to the cathode side of the bipolar electrode system.

The sealing system of the electrolyte surface is a high-temperature-resistant alumina insulating plate, which is in contact with the electrolyte in the working area, and the high-temperature-resistant alumina insulating plate sinks into the electrolyte by 5-10 mm.

The decontamination surface sealing system also includes a separator, which is in contact with the electrolyte in the working area and protrudes into the electrolyte by 20-50 mm.

Due to the adoption of the above structure, the device has been greatly improved compared with the current contact method calcium electrolyzer. First of all, compared with the traditional contact method calcium electrolyzer, the bipolar electrode proposed by Benfen has fundamentally changed the original mode of using iron rod as the cathode, so that the production capacity of the electrolyzer has increased geometrically. Secondly, the present invention not only facilitates the enrichment and convenient precipitation of metallic calcium, but also facilitates the discharge of chlorine gas generated by the anode through the design of the upper sealing and partitioning device, so that large-scale continuous industrial production of calcium electrolysis can be realized. Therefore, the calcium electrolyzer provided by the present invention can fully avoid the defects of low production capacity, inconvenient operation and high energy consumption of the current contact method calcium electrolyzer, and it can be the development direction of the next generation of contact method calcium electrolyzer.

Compared with the existing contact method calcium electrolyzer structure, the present invention has the following advantages:

(1) The application of the electrolytic cell of the present invention can greatly increase the production capacity of a single cell of calcium electrolysis and reduce the investment cost of the electrolytic cell. Since the calcium electrolytic cell of the present invention is equivalent to several small calcium electrolytic cells connected in series in one cell, the production capacity of a single cell can undergo qualitative changes, and due to the arrangement of bipolar electrodes, the utilization rate of the space in the electrolytic cell is extremely high. High, greatly reducing the investment cost of calcium electrolyzer.

(2) Applying the electrolyzer of the present invention can realize the continuity and low energy consumption of the calcium electrolysis process. The obtained metal calcium still gathers in the upper part of the tank, but different from the current method, the present invention allows the metal calcium to be under the protection of a partition isolated from the outside world, and can be precipitated in a vacuum very conveniently, so the electrolysis process is a continuous, The process of low energy consumption can be extended according to the actual situation of single slot or series expansion of multiple slots, so large-scale industrialization will also become very easy.

(3) The application of the electrolytic cell of the present invention can realize fast and efficient maintenance of the electrolytic cell. Since the bipolar plate material of the electrolytic cell is relatively common, its maintenance management and calcium precipitation operation will become very fast and efficient, and because the anode is not consumed, the electrolytic cell can run stably for a long time.

To sum up, the present invention is an electrolytic cell capable of direct large-scale, continuous and high-efficiency production of metallic calcium by the contact method, which can provide guarantee for the large-scale, low-energy, and low-cost preparation of industrial high-purity calcium.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a schematic structural diagram of a bipolar plate of the present invention.

Fig. 3 is a schematic diagram of the conductive network in the bipolar plate of the present invention.

In the figure, 1-bipolar electrode system, 2-electrolyte surface sealing system, 3-lining insulation system, 4-upper gas collection system, 5-chlorine gas escape and feeding port, 6-baffle plate, 7-metal calcium Suction outlet, 8-electrolyte, 9-insulation cover, 10-insulation layer, 11-calcium metal, 12-mesh conductive skeleton, 13-branch conductive wire, 14-conductive rod, 15-connecting bus bar.

detailed description

The present invention will be further described in detail below in conjunction with the drawings and specific implementation process.

Example 1:

As shown in Figure 1, a calcium metal electrolyzer using bipolar electrodes consists of a bipolar electrode system 1, an electrolyte surface sealing system 2, a lining insulation system 3, and an upper gas collection system 4. Among them, the electrolyte surface sealing system is equipped with chlorine gas escape and discharge port 5, separator 6 and metal calcium suction port 7, and the lining insulation system includes insulation system, insulation system and tank shell support system.

The bipolar electrode system 1 of the calcium electrolyzer is composed of a whole piece of graphite carbon block. Copper, including multiple groups of vertically equidistant conductive groups, each group of conductive groups includes a connecting bus bar 15, a plurality of conductive bars 14 installed on the connecting bus bar 15, and a plurality of branch conductive wires 13 installed on the conductive bar 14 , as shown in Figure 3, in this example, the conductive group is provided with five groups, and five connecting bus bars 15 are connected by the main conductive rod, and four conductive rods 14 are symmetrically installed on each connecting bus bar 15 with the main conductive rod as the center, Two pairs of branched conductive wires 13 are symmetrically installed on the conductive rod 14 to form a herringbone conductive branch. The conductive rod 14 and the branched conductive wire 13 form a tree-rooted conductive structure. In this example, each tree-rooted structure contains two herringbone-shaped conductive branches. , the conductive rod 14 is arranged between the two electrodes of the bipolar electrode system 1, the diameter of the main conductive rod is 1-3 mm, and the main conductive rod is connected with the outer diameter. The material of the electrolyte surface sealing system 2 can be a high temperature resistant alumina insulation board, which needs to cover the entire upper surface of the electrolyte 8 and be immersed in the electrolyte. There is a chlorine gas escape and feeding port 5 on the top, which is a round hole with an aperture of 30-150 mm, and its position is close to the anode side; a separator 6 is installed at the middle and lower part of the electrolyte surface sealing system 2, and its material is the same as that of the electrolyte surface. The material of the sealing system 2 is the same, and it is advisable to protrude into the dielectric medium by 20-50mm. The metal calcium suction port 7 is located on the side close to the cathode.

The bipolar electrode used in this embodiment can fundamentally change the original iron rod as the cathode mode, so that the production capacity of the electrolytic cell has been increased geometrically. In addition, by designing the upper sealing and partition device, it is beneficial to The enrichment and convenient precipitation of metallic calcium are also conducive to the discharge of chlorine gas generated by the anode, so that large-scale continuous industrial production of calcium electrolysis can be realized.

Example 2:

As shown in Figure 2, the bipolar plate structure of the novel calcium electrolyzer is a structure that separates the positive and negative electrodes. Rod, to balance the current distribution in the bipolar plate, the other parts of the calcium electrolyzer are the same as in Example 1. Using the electrolytic cell can also realize the production of low energy consumption, high efficiency and high capacity in the calcium metal electrolysis process.

Claims (9)

1. A calcium metal electrolyzer that adopts bipolar electrodes is characterized in that: it comprises a bipolar electrode system (1), an electrolyte surface sealing system (2) and a liner insulation system (3) arranged in the tank shell , the inner liner insulation system (3) comprises an insulation layer and an insulation layer wrapped on the outside of the insulation layer, the insulation layer encloses an electrolysis zone with an upper opening, and the electrolysis zone is surrounded by an adjacent bipolar electrode system ( 1) Divided into multiple separate working areas, the bipolar electrode system (1) in each working area is opposite to the electrode on the working surface, and the upper opening of each working area is sealed by the electrolyte surface sealing system (2), so The electrolyte surface sealing system is provided with a chlorine gas escape and feeding port (5) and a metal calcium suction port (7). 2. The metal calcium electrolyzer adopting bipolar electrodes according to claim 1, characterized in that: the bipolar electrode system (1) comprises a bipolar electrode, and the bipolar electrode is provided with a net shaped conductive skeleton (12). 3. The metal calcium electrolytic cell adopting bipolar electrodes according to claim 2, characterized in that: the mesh conductive framework (12) comprises a main conductive rod and a plurality of conductive groups distributed vertically and equidistantly on the main conductive rod , the main conductive rod is arranged between the two electrodes of the bipolar electrode, and each group of conductive groups includes a connection bus bar (15), a plurality of conductive rods (14) installed on the connection bus bar (15) and a plurality of conductive rods (14) installed on the conductive rod (14) a plurality of branch conductive wires (13), a plurality of said connecting busbars (15) are connected by main conductive rods, and each connecting busbar (15) is respectively installed with multiple conductive wires on both sides of the main conductive rods. A rod (14), the conductive rod (14) is equipped with a branch conductive wire (13), and the conductive rod (14) and the branch conductive wire (13) form a tree-like conductive structure. 4. The metal calcium electrolytic cell adopting bipolar electrodes according to claim 2, characterized in that: said bipolar electrodes are composed of cuboid graphite carbon blocks with a thickness of 50-100mm, and the length and width are the same as those of the electrolytic cell. Sizes match. 5 . The metal calcium electrolytic cell adopting bipolar electrodes according to claim 4 , characterized in that: an upper gas collection system ( 4 ) for sealing the upper opening of the electrolytic zone is arranged above the cell shell. 5 . 6. The metal calcium electrolytic cell adopting bipolar electrodes according to claim 5, characterized in that: the chlorine gas escape and feeding opening (5) is a circular hole with an aperture of 30-150 mm, and the chlorine gas escape and feeding The port is near the anode side of the bipolar electrode system. 7. The metal calcium electrolytic cell using bipolar electrodes according to claim 6, characterized in that: the metal calcium suction port is close to the cathode side of the bipolar electrode system. 8. The metal calcium electrolytic cell adopting bipolar electrodes according to claim 7, characterized in that: the electrolyte surface sealing system (2) is a high-temperature-resistant alumina insulating plate, and the high-temperature-resistant alumina insulating plate In contact with the electrolyte in the working area, the high-temperature-resistant alumina insulating plate sinks into the electrolyte by 5-10 mm. 9. The metal calcium electrolyzer adopting bipolar electrodes according to any one of claims 1 to 8, characterized in that: the solution surface sealing system (2) also includes a partition, and the partition and the The electrolyte is in contact and extends 20 to 50mm into the electrolyte.