US1970076A - Electrolytic process for the manufacture of chemical compounds - Google Patents

Description

Patented Aug. 14, 1934 UNITED STATES PATENT OFFICE ELECTROLYTIC PROCESS FOR THE MANU- FACTURE OF CHEMICAL COMPOUNDS Antonio Llorens Clariana, Valldemosa, (Balearic Islands), Spain 2 Claims.

This invention relates to an electrolytic process for manufacturing chemical compounds.

In certain processes for the manufacture of chemical compounds by electrolysis it is necessary, in order to secure satisfactory working, to prevent the production of hydrogen at the oathode of the plant, or to remove such hydrogen periodically.

One object of the invention is the provision of a process in which the production of hydrogen at the cathodes of an electrolytic plant is avoided by the use of cathodes made of or provided with a layer of very fine particles of a metal easily oxidizable in air.

A further object of the invention is the provision of a process in which the cathodes of an electrolytic plant are periodically oxidized by being lifted out of the electrolyte into contact with the air for a period of time such that the oxygen taken by the cathodes is suflicient for checking the reduction action to which they will be submitted during the following electrolytic action.

Other features and objects will be apparent from the following description and from the claims appended thereto.

The process of the present invention consists in the fulfilment of the aforementioned desideratum, namely that the production of hydrogen at the cathodes, in electrolytic plants used in the manufacture of certain chemicals, shall be avoided.

This is obtained by the use of cathodes made of or provided with a layer of a sponge or very fine particles of a metal easily oxidizable in the atmosphere. In order to rejuvenate such a metal so as to obtain satisfactory working, the cathodes are periodically oxidized by being lifted out of the electrolyte into contact with the air for a period of time such that the oxygen taken by the cathodes is sufficient for checking the cathodic reduction during the following electrolytic action.

This alternation in the working of the cathodes may be obtained by filling and emptying periodically the electrolytic vats, or by the use of multiple cathodes so as to allow one set to be submerged and the other to be in the air, and vice versa, alternately, or by giving a slow movement of rotation to the cathodes which are partially submerged.

Thus, in the manufacture of lead hydroxide by this process, the electrolyte may be a solution of sodium chlorate, the electrodes of lead, and the cathodes with a thin layer of lead sponge precipitated on them. Density of current, 0.5 amperes per square decimetre; voltage 1.3 volts per vat.

The alternating periods of activity and rest of the cathodes are of about 45 minutes duration. There are, in this case, no diaphragms. The hydroxide produced is poured from the vats with the electrolyte after the said period of 45 minutes of electrolytic action, and then collected by decanting. In certain cases diaphragms may be provided in the vats. By immersion in this specification and in the appended claims is meant also partial immersion.

It will be understood that modifications may be made in the process described without departing from the scope of the invention as defined in the appended claims.

What I claim is:--

l. The process of rejuvenating the electrodes of an electrolytic bath, comprising forming a bath of sodium chlorate, employing lead electrodes, forming a layer of lead sponge on the cathodes, inserting the electrodes in the bath, and after producing lead hydroxide by the electrolytic action, periodically oxidizing the cathodes to prevent the collection of hydrogen thereabout.

2. The process of rejuvenating the electrodes of an electrolytic bath, comprising forming an electrolyte of a sodium chlorate solution, forming the electrodes of lead, forming a thin layer of lead sponge on the cathodes, inserting the electrodes in the bath, passing a current between the electrodes and through the bath at a density of approximately 0.5 amperes per square decimeter at a pressure of approximately 1.3 volts, and after producing lead hydroxide by such action, periodically oxidizing the cathodes to prevent the formation of hydrogen thereabout. 9o

ANTONIO LLORENS CLARIANA.