RU22146U1 - ANODE FOR ELECTROLYSIS OF ALKALINE SOLUTIONS - Google Patents

Description

ANODE FOR ELECTROLYSIS OF ALKALINE SOLUTIONS.

The useful model relates to electrochemical production, in particular, to the field of manufacture of electrodes for oxygen evolution by the electrolytic decomposition of alkaline solutions and can be used, for example, in small-sized installations for the production of hydrogen-oxygen mixtures used in welding operations.

Known electrodes for the electrolysis of aqueous alkaline solutions, containing a conductive metal base with an active coating deposited on it, for example, a steel base and an active coating — a nickel layer III, a nickel base coated with an active coating in the form of a nickel-cobalt 121 alloy, steel, steel nickel or nickel electrocatalytic substrate with an active composite metal oxide-hydroxide coating deposited on it containing nickel and iron / 3 / ..; , V

In industry, in plants for the production of hydrogen and oxygen by electrolysis of aqueous alkaline solutions, electrolyzers such as SEU-10-2 (TU 26-01-739-78) are used, developed by the Uralhimmash plant, which use a bipolar cathode and a monopolar anode on steel basis, where the monopolar anode has an active deposited nickel coating.

However, the known electrodes on a conductive metal base do not possess corrosion resistance in alkalis, strength and resistance to S25B 11/00

visa, the disadvantages are also the complexity and duration of the active coating using electroplating.

The closest in technical essence and the achieved technical result is an anode for the electrolysis of alkaline solutions containing a conductive base of steel, nickel-plated steel or nickel coated with an active composite metal oxide-hydroxide coating containing nickel and iron, with the following ratio of components in the coating, wt.% :

No. 40-63; Fe 5-27; 0; OH 13-40.

The disadvantages of this device are the high mass of the structure, its high cost due to the use of a large amount of expensive scarce material - nickel, a rather complicated manufacturing technology of the electrode using electroplating, and, as a result, the large time required to regenerate the active working layer of the anode.

The objective of this utility model is to reduce the weight of the structure, reduce the time required to apply and regenerate the working layer of the anode, create an anode with a lower overvoltage of oxygen penetration, and simplify the technology of manufacturing the anode.

This goal is achieved by the proposed anode for the production of oxygen and hydrogen by electrolysis of aqueous alkaline solutions, including a conductive base and an active coating deposited on it, and as a conductive base, the anode includes a polymer disk with a plasma spraying of a nickel layer in the amount of 80-100 mg / cm of the visible electrode surface, and as an active coating, the anode includes a magnetite layer deposited by plasma spraying in an amount of 1100-1200 mg / cm of the visible surface electrode.

The polymer disk may be made of fluoroplastics, polypropylene, polystyrene or rigid polyvinyl chloride.

The essence of this utility model is as follows. The design of the electrode consists of a polymer disk, in which three holes are drilled for attaching the current lead using fixing screws. The disk is made of a polymeric material having good strength characteristics, corrosion resistance in alkalis and adhesion to the applied coatings. Such materials as fluoroplastics, polypropylene, polystyrene, rigid polyvinyl chloride satisfy these requirements. A polymer disk made of fluoroplastics is treated on the surface with sodium naphthalene or another complex compound of alkali metals to improve adhesion properties. On the surface of the polymer disk is applied by plasma spraying a layer of nickel in an amount of 80-100 mg / cm of the visible surface of the electrode. Next, the disk is assembled with a current lead made of titanium using steel screws. Then, a working layer consisting of magnetite in the amount of 1100-1200 mg / cm of the visible surface of the electrode is also deposited on the nickel working layer by plasma spraying. A layer of magnetite is coated with a coating of fixing screws. Plasma spraying is carried out in an inert gas jet of a plasma torch - spray gun and is characterized by the following parameters: standard sprayer of the UPUZD installation, power 15-18 kW, spraying distance - 100mm, blowing distance with a slotted nozzle - 10mm.

Time spent on coating:

nickel - 2-3 minutes

magnetite - 8-10 minutes

The technical essence of the utility model is illustrated by the drawing, where figure 1 shows a diagram of the anode, and figure 2 shows a section of the anode.

The use of a polymer disk in the design of the anode makes it possible to reduce the weight of the anode structure by 5 times compared to the known one.

Using the plasma spraying method makes it possible to reduce the time required for application (in the prototype - 20 ZOmin.), As well as for the subsequent regeneration of this layer and makes the basis of the anode conductive.

The application of the active coating of the anode as a working layer of magnetite as a working layer allows the process to be carried out at a lower overvoltage of oxygen evolution compared to the known one, using the plasma spraying method also reduces the consumption rates of magnetite raw materials and also reduces the time spent on coating and subsequent regeneration of the working layer. The use of magnetite does not require any chemical treatment, it is cheap and quite affordable in nature. In operating mode, the anode operates as follows.

After filling the apparatus with a solution of caustic potassium, the anode is polarized by an external current to the oxygen evolution potential. The resulting oxygen bubbles rise up and collect in the receiving chamber.

The proposed model is illustrated by the following examples:

Example 1

The disk is made of polypropylene. On the surface of the polymer disk, a layer of nickel is applied by plasma spraying in an amount of 80 mg / cm of the visible surface of the electrode. Next, the disk is assembled with a current lead made of titanium using steel fixing screws. Then, a working layer consisting of magnetite in an amount of 1100 mg / cm of the visible surface of the electrode is also deposited on the nickel working layer by plasma spraying. A layer of magnetite is coated with a coating of fixing screws. Plasma spraying is carried out in an inert gas jet of a plasma torch - sprayer and is characterized by the following parameters: standard sprayer of the UPU-ZD installation, power 15 kW, spraying distance - 100 mm, blowing distance with a slot nozzle 10 mm.

Example 2

The disk is made of ftoroplast. To improve the adhesion properties, the surface is treated with sodium naphthalene or other complex compounds of alkali metals. On the surface of the polymer disk is applied by plasma spraying a layer of nickel in the amount ///

5

with a conductive made of titanium using steel fixing screws. Then, a working layer consisting of magnetite in the amount of 1200 mg / cm of the visible surface of the electrode is also deposited on the nickel working layer by plasma spraying. A layer of magnetite is coated with a coating of fixing screws. Plasma spraying is performed in an inert gas jet of a plasma torch - sprayer and is characterized by the following parameters: standard sprayer of the UPU-ZD installation, power 18 kW, spraying distance - 100 mm, blowing distance with a slot nozzle 10 mm.

The resulting electrodes are tested in a 30% potassium hydroxide solution at a current density of 20-30 A / dm.

The data are presented in the table.

Table

As can be seen from the above data, the potentials of the magnetite anode are lower than the potentials of the known anode, as a result of which the overvoltage of the main process is reduced.

Therefore, the proposed design of the anode has a lower weight compared to the known one, which allows it to be used in small-sized installations for the production of oxygen and hydrogen, used, for example, during welding. In this utility model, anode manufacturing technology is simplified by the method of plasma spraying, which further reduces the time spent on applying nickel and magnetite layers and their further regeneration. The use of the anode allows the process to be carried out at a lower overvoltage of oxygen evolution.

USED BOOKS.

1. Certificate of authorship No. 1393851, application No. 4060252 / 31-6, filed January 30, 1986, published May 7, 88, Bull. No. 17, 11/04

2. Author's certificate No. 627183., application No. 2368116 / 23-26, filed 02.06.76, published 05.10.78, Bull. No. 37, 11/06

3. Certificate of authorship No. 1579938, application No. 4421375 / 23-26, filed March 31, 88, published July 23, 90, Bull. No. 27, 11/06 (prototype).

Claims (2)

1. An anode for the electrolysis of alkaline solutions, containing a conductive base and an active coating based on iron compounds, deposited on it, characterized in that, in order to reduce the weight of the structure, simplify the manufacturing technology of the anode, reduce the overvoltage of oxygen evolution, the anode includes a polymer disc applied thereto by plasma spraying a layer of nickel in an amount of 80-100 mg / cm ^2, and, as an active anode coating comprises magnetite layer in an amount of 1100-1200 mg / cm ^2, nanesennog by plasma spraying. 2. The anode according to claim 1, characterized in that the polymer disk is made of fluoroplastics, polypropylene, polystyrene or rigid polyvinyl chloride.