Hoechst Aktiengesellschaft

Uhde Gmbh

Hoeschst Aktiengesellschaft

Dieter Bergner

Kurt Hannesen

Wilfried Schulte

Wolfgang Muller

Helmut Hund

Lothar Pelz

Werner Bender

Winfried Hofmann

Jurgen Russow

Helmuth Schurig

Rudolf Staab

Theodor Auel

Helmut Schmitt

Nikolaj Medic

Gerhard Quietzsch

Max Danner

Peter Steinmetz

Ortwin Kuster

Manfred Hartmann

Erhard Heubach

Helmut Schaefer

In the electrolysis apparatus for the production of chlorine, sodium hydroxide solution and hydrogen from aqueous alkali-metal halide solutions, which electrolysis apparatus comprises at least one electrolysis cell, anode and cathode, which are separated from one another by a partition, are disposed in a housing composed of two half-shells electrically separated by an insulating seal. The housing is provided with devices for supplying the electrolysis starting substances and for removing the electrolysis products, the latter comprising at least one discharge pipe which extends in the vertical direction in the interior of the half-shells, passes through the half-shell in the vicinity of the lower edge and extends up to the upper edge. The discharge pipe (9, 10) terminates in a separating chamber (14, 15) which is disposed in a stilling zone. The stilling zone is formed by a plate (11, 12) attached to the electrode (4, 5) and to the associated half-shell (1, 2).

Electrolysis apparatus

An electrolyzer for the production of chlorine from an aqueous alkaline halide solution includes a plurality of electrolysis cells each having a housing of two half-shells. The bottom side of each of the half-shells is in a plane parallel to a plane of an adjacent anode or cathode, the space between the bottom side and the anode or the cathode being provided with framework-pattern metallic reinforcements. Each bottom side has one or more contact strips attached to its outer surface which are arranged in a congruent position to the contact strips on the bottom side of the adjacent electrolysis cell, and extend over the length or width of the cell. The contact strips are aligned with and connected by electrically conducting means to part of the framework-pattern reinforcements and the unperforated sections of the adjacent anode or cathode. The two half-shells and a membrane partition wall are assembled to form an electrolysis cell sealed by two gaskets.

Electrolyzer

In this electrolysis apparatus for the preparation of chlorine from aqueous alkali halide solutions, which comprises at least one electrolytic cell, the anode and gas diffusion cathode are disposed horizontally and separated from each other by a partition in a housing consisting of two half shells and are connected mechanically and in an electrically conducting manner by means of their edges to the respective half shells. In addition, the cathode is connected in a liquid-tight manner to its half shell and is supported by a current supply and distribution device. The partition is clamped between a circumferential seal between the edges of the half shell and a frame and is supported on a spacer which rests on the cathode and is held by the frame. The frame contains an inlet and outlet for the catholyte.

Electrolysis apparatus with horizontally disposed electrodes

The electrolysis apparatus for the manufacture of chlorine from aqueous alkali metal halide solutions has at least one electrolysis cell the electrodes of which, separated by a separating wall, are arranged in a housing of two hemispherical shells. The housing is furthermore provided with equipment for the feed of the starting materials for electrolysis, and equipment for the discharge of the electrolysis products. The separating wall is clamped by means of sealing elements between the rims of the hemispherical shells and positioned between power transmission elements of non-conductive material. The electrodes are fastened via spacers to the inner walls of the shells and connected mechanically and electrically with the shells via the rims thereof.

The electrolysis apparatus for the manufacture of chlorine from aqueous alkali metal halide solutions has at least one electrolysis cell the electrodes of which, separated by a separating wall, are arranged in a housing of two hemispherical shells. The housing is furthermore provided with equipment for the feed of the starting materials for electrolysis, and equipment for the discharge of the electrolysis products. The separating wall is clamped by means of sealing elements between the rims of the hemispherical shells and positioned between power transmission elements of non-conductive material. The electrodes are fastened via spacers to the shells and connected mechanically and electrically with the shells via the rims thereof. The hemispherical shells of adjacent cells are positioned flatwise one upon the other, and the end positioned shells of the electrolysis apparatus are supported by pressure compensation elements.

In the electrolysis of an aqueous alkali metal chloride solution, a mixture of anolyte and steam-saturated gaseous chlorine is formed in the anode space of the electrolytic cell. According to the invention, the process is carried out under a pressure of at least 8 bars. For workup, the anolyte is at first separated from the steam-saturated gaseous chlorine which is then liquefied under a pressure of at least 8 bars by cooling. In the course of cooling there is obtained a condensate which consists of a liquid water-saturated chlorine phase and a liquid chlorine-saturated water phase. The temperature of said condensate is not to fall below 28.degree. C. during cooling. Finally, the light-weight water phase is separated from the chlorine phase having a heavier specific weight.

Process for the production of liquid chlorine

The electrolysis of aqueous alkali metal chloride solutions under pressure has already been carried out. In accordance with the invention there is applied a pressure of at least 8 bars in the anode space for such an electrolysis, as well as a special process for the work-up of the products of the anode space. The mixture of gas and anolyte leaving the anode space is at first mechanically separated, and the anolyte is then depressurized into a stripping column. In the course of this process a dechlorination and cooling of the anolyte are taking place. The anolyte is to enter the pressure release vessel (stripping column) with a temperature being above the boiling point of the anolyte at atmospheric pressure. The reduced pressure is to be between 2 bars and atmospheric pressure. By means of these measures it may be ensured that the anolyte in the stripping column reaches boiling point. Finally the chlorine set free in the pressure release operation is separated from the anolyte.

Process for the dechlorination and cooling of the anolyte of the alkali

For the indirect measurement of the distribution of the anode currents in electrolytic cells operated with alkali metal chloride according to the amalgam process the cell voltage is determined without unnecessary ohmic connections between the current carrying elements of the cells and other conductive elements thereof.

Apparatus to measure the distribution of the anode currents in cells for

For the electrolysis of an aqueous alkali metal chloride solution in a membrane cell with a perfluorinated cation exchange membrane it is important that there is only a minimum amount of cations of polyvalent metals, such as calcium. Otherwise, deposits within the membrane will occur, among other effects. It has been found that the disturbances caused by the above-mentioned cations can be considerably reduced, if an aliphatic polybasic phosphonic acid or the alkali metal salt thereof is added to the alkali metal chloride solution.

Process for alkali metal chloride electrolysis

Equipment for controlling, monitoring, determining the most effective operating conditions and operating, and for displaying data in, alkali metal chloride electrolysis plants which are operated by the amalgam process, wherein the equipment has, for each electrolytic cell or for each group of electrolytic cells, a data collecting and processing device for controlling, monitoring and determining the most effective operating conditions the electrolytic cell or group, and all the data collecting and processing devices are connected to a central data collecting and processing device for central operation and for displaying data.

Equipment for regulating, monitoring, optimizing and operating, and for

When aqueous solutions of aluminum chloride or of basic aluminum chloride having the formula Al.sub.2 (OH).sub.m Cl.sub.6-m wherein m is a number from 0 to 5.3 are submitted to electrolysis chlorine is removed and the Al/Cl ratio of the solution increases. The electrolysis is performed without diaphragm. Graphite anodes cannot be used. It is possible to process the resulting solutions to solid basic aluminum chloride having the formula Al.sub.2 (OH).sub.n Cl.sub.6-n wherein n is a number from 1 to 5.34.

Process for preparing basic aluminum chlorides

A long-term electrode for electrolytic processes comprises a skeleton of a metal passive under the conditions of the electrolytic process and an electrically conductive first coating which is bound to the metal skeleton in a tightly adhesive manner covering at least part of the metal surface and to which is applied electrochemically active substances selected from the group of platinum metals and platinum metal compounds. The first coating is produced on the metal surface by flame or plasma spraying. Subsequently at least one electrochemically active substance containing a platinum metal or oxide thereof is formed by a thermal degradation process and anchored to the pores of the first coating.

Method of making long-term electrode for electrolytic processes

In an electrolytic apparatus for the production of chlorine from aqueous alkali metal chloride solution, comprising at least one electrolytic cell with equipment for the supply of the current, the supply of the starting product and the discharge of the products of electrolysis and a separating wall for separating the anode and cathode, the housing of the cell is composed of two hemispherical shells, the electrodes are connected with the hemispherical shells by conductive bolts projecting through the wall of the shells and the projecting end faces of the bolts are in contact with current supply means and means to clamp together the supply means, the shells, the electrodes and the separating wall, which wall is positioned between electrically insulating spacers mounted in the extension of the bolts on the electrolytically active side of the electrodes and clamped between the edges of the hemispherical shells by packing elements.

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Kelkheim, Germany

Dieter Bergner