JPS5861560A - Zinc powder for electrochemical battery and method of producing same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new method for the preparation of zinc powder intended for the production of electrochemical cells, the curved lead powder being in the form of an electrode, obtained for example by compaction. . Batteries containing electrodes made of zinc powder, whether alloyed or not, allow harmful escape of gas (hydrogen) when the cell is not producing current, reducing capacity and creating structural problems. is publicly known.

It is known to avoid such escape of gases by means of known powder blends.

However, the amount of mercury used in this known process is relatively important and the incorporation itself constitutes an expensive and delicate operation. However, this method has the disadvantage of non-homogeneous distribution of mercury.

The present invention avoids the above drawbacks.

The present invention is used in a method for manufacturing zinc powder for electrochemical batteries that requires the presence of mercury, and part or all of the mercury required for batteries is introduced into molten zinc regardless of whether it is an alloy or not. The molten alloy is homogenized and conveyed into powder by grinding.

The powder obtained by the method of the invention is characterized in that, together with the zinc, it is contained in the powder forming the form of a homogeneous alloy.6° As a result, the mercury is distributed equally in each size of powder until the complete evacuation of the metal. It will be effective in a predetermined amount.

example Nine parts of molten zinc are mixed with six parts of mercury.

This mixture becomes homogeneous at a temperature of about 420°C.
% water plate alloy is produced. This molten alloy is then pulverized with compressed air at a pressure of 3XIOPa,
A powder with a particle size in the range of 100N500.4 is then obtained.

The powder thus produced has the following advantages compared to conventional mercury-containing zinc powder:

(The rate of 1,1 gasification is very low, meaning that only a very small amount of hydrogen escapes when it comes into contact with an alkaline electrolyte.) An electrolyte consisting of 12N potassium hydroxide saturated by a l!lI conversion vessel. In the book, a powder book showed a gas evolution of 1.5 microliters per gram per day at 45°C, whereas zinc powder containing 6% mercury was produced by contacting an aqueous mercury melt. The conventional mercury-containing zinc powder produced exhibits a gas evolution rate of 5 microliters per gram per day under the same conditions.

(27 Powders of all particle sizes, which can be large or small, have the same mercury content jt (6%), whereas in traditional mercury-containing zinc powders, small particle sizes have more mercury content than large particle sizes. .

As a result of the above two advantages, when using the powder of the invention instead of conventional powders to make batteries, it is possible to use powders with low mercury content and small particle size;
This results in an increase in the electrical capacity of the battery.

Claims (1)

[Claims] (υ(, JII l & mixing zinc with an amount of mercury effective to suppress gas formation; (0) The molten alloy homogenized in the step (9) is pulverized to obtain a powdered zinc-mercury alloy, and each particle size of the powder is A method for producing a powder electrode material for use in an electrochemical cell using mercury-containing zinc powder as an electrode material, characterized by the steps of: (14) (- mixing molten zinc with an amount of mercury effective to suppress gassing; (1) homogenizing the resulting molten mixture of said step (-) to obtain a homogenized molten alloy of zinc and mercury; (c) pulverizing the homogenized molten alloy from step (b) to obtain a powdered zinc-mercury alloy, each particle size of the powder consisting of a homogeneous zinc-mercury alloy; In zinc powder for electric and vaporization half-cells produced by a method for producing powder electrical materials for use in electrochemical cells that uses zinc powder containing mercury as an electrical material, which requires more steps, Zinc powder is characterized by being composed of a homogeneous zinc-mercury alloy with the same particle size.