SU1033578A1 - Cathode for electrolysis of acid solutions - Google Patents

Abstract

1. CATHODE FOR ELECTROLYSIS. KISSH SOLUTIONS containing iron, Chromium, nickel, molybdenum and copper, O t and h and with the fact that, with 1Sec | ls.; Jaag; r., G.j.JPlik: yU yoLyOSh. in order to reduce energy consumption for electrolysis by reducing the overpotential of hydrogen evolution, it additionally contains a transition metal of group IV or V of periodic, systbl elements in the following ratio of components, wt.%; Chromium 17-25 Nickel 22-29 Molybdenum 2.5-3.0 Copper 2.5-3.0 Transition metal IV or V of group 0.3-10 Iron Else With S 2. The cathode according to claim 1, about t l and the fact that as (L of the transition metal it contains titanium or niobium.

Description

WITH

with

01

l

cx The invention relates to electrochemistry, in particular, to materials for the manufacture of cathodes used in the electrolysis of acidic media during the production of hydrogen, persulfuric acid and its salts. The choice of cathode materials operating in acidic environments is very limited due to their significant corrosivity. It is known to use for electrolysis solutions of sulfuric and hydrochloric acid of graphite cathodes characterized by a high corrosion resistance, t 1. However, at the same time, graphite is a technological material, and cathodes made from it are characterized by a high overvoltage of hydrogen evolution. The closest in technical essence and the achieved result to the proposed is cathode material for electrolysis of acidic solutions containing iron, chromium, nickel, molybdenum and copper, for example, steel grade Х18Н28МЗДЗ (ЭИ530), containing, wt.%: Carbon less than 0.1 chromium 17-19, nickel 27-29, molybdenum 2.5-3, copper 2.5-3, iron - the rest 2, Made of this steel, which has good corrosion resistance in acidic environments, the cathodes have satisfactory electrochemical characteristics, but characterize quite high perenap The release of hydrogen on them. Thus, during the electrolysis of solutions of sulfuric acid with a densely supplied current of 1000–3500 and a temperature of 25 ° C, this figure is 0.45-0.75 V. The aim of the invention is to reduce the energy consumption for electrolysis by reducing the overvoltage. However, hydrogen evolution on cathodes made of corrosion-resistant materials for operation in acidic environments. This goal is achieved by the fact that the cathode for the electrolysis of Kilium solutions containing iron, chromium, nickel, molybdenum and copper contains a transition metal or group V of the periodic system of elements / a component taken in the ratio, weight,%: Chrome 17- 25 Nickel in Molybdenum 2.5-3.0 Copper 2.5-3.0 Transition metal 1 or N of group 0.3-10 Iron Else At the same time, as the transition j of metal, the cathode contains M (metal of group IV py is titanium or Niobium metal Y group - Introduction to the material for the manufacture of the cathode of transition metals of group IV or V of the periodic system elements facilitate the process of discharge and recombination of hydrogen due to the ability of these metals to adsorb hydrogen up to the formation of hydrides. Of these groups of metals, the best results are achieved with the introduction of titanium or niobium. The optimum addition of these metals is 1 wt.% and with a further increase amounts of up to 10% of the amount of overvoltage of hydrogen evolution decreases slightly. The addition of supplements over 10% does not have any noticeable effect on the amount of overvoltage of hydrogen evolution. Examples 1-4. 4 mixtures are prepared with minimum and optimum qualities of transition metals, each of which contains, wt%; chromium 21, nickel 25.5, molybdenum 3, copper 3, and two of the mixtures additionally contain titanium, and the other dienobium in amounts of 0.3 and 1.0 wt.% each. The rest up to 100% in all four mixtures is iron. Each mixture is fused separately in crucibles in electric arc furnaces. Cathodes are made from the resulting alloys. Examples 5 and b. For the floor, 1vni cathode material with a maximum content of transition metals on the working surfaces of cathodes containing 1 volC.% Of titanium and niobium and obtained according to the above examples, using thermal diffusion method, bring their content to 10 wt.%. For this, in the case of titanium , saturation of the cathode working surface, placing a sample of the cathode material in an ampoule containing powdered, wt.%: PTAM 75 grade titanium, alumina 24 and ammonium chloride 1. Next, the ampoule is placed in a furnace and in hydrogen atmosphere for 3 hours. To saturate the working surface of the cathode with niobium, use a mixture containing powdered, wt.%: niobium 50, alumina 49, ammonium chloride 1. The surface is saturated as described in ° C for 4 hours .

.-. The cathodes obtained according to examples 1-6 are tested in 1 and 5 molar solutions of sulfuric acid at current densities of 1000-3500 A / m and electrolyte temperature. Overvoltage (at) with Additive, wt.% 1000 G 1500 I

Titanium 0.3

0.3

1.0

0.18

Lo

0.25

After 1.5 hours of operation, the overvoltage of hydrogen evolution is measured at each of the cathodes. Test data is given in table .0, 40

0.35

0.33

0.24

0.26

0.22

0.36

0.33 current density, A / m 2000 I 3500

As can be seen from the table, the overpotential of hydrogen evolution is 0.15-0.40 V, which is 0.30-0 j 35 V below the same value as the prototype (0.450, 75. Optimal addition of titanium and niobium is 1 wt.%, because it provides minimal overpotential hydrogen evolution made from the proposed cat material.The application of the proposed cathode material in applied electrochemistry ensures low wear of such cathodes while making them workable in the manufacturing process by replacing brittle, wear and tear direct .i malotehnologichnogo graphite to metal, and reduced-j n.ie power consumption for 1000- I 1300 kWh per 1 ton of 100% hydrogen peroxide obtained through persulfuric acid, or 1,200 kWh in the preparation of 1000 cubic hydrogen.

Claims (1)

· 1. Cathode for electrolysis. ACID SOLUTIONS, containing iron, Chromium, nickel, molybdenum and copper, with the fact that, in order to reduce energy consumption for electrolysis by reducing the overvoltage of hydrogen evolution, it additionally contains transition metal IV or V group periodic. systems! elements in the following ratio of components, wt.%: Chromium 17-25 Nickel 22-29 Molybdenum 2.5-3.0 Copper 2.5-3.0 Transition metal IV or V group py 0.3-10 Iron Rest 2. Cathode by p. 1, about l and h a- 19 with the fact that as transition metal it contains ω titanium or niobium. SS SO SP oo>