Method for making highly oxidized lead powder used for a lead storage battery
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsHiroshi Yasuda, Kazuyoshi Yonezu, Katsuhiro Takahashi, Kenzo Yamamoto
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Abstract
Highly oxidized lead powder containing red lead not more than 90% is efficiently produced by maturing the lead powder material at a low temperature section of a furnace keeping the temperature less than 100.degree. C. by spraying water to the material and then, by heating the same from 400.degree. to 500.degree. C. at a high temperature section of the furnace. The highly oxidized lead powder produced in this method is preferable as active material of a lead storage battery, that is, a paste preparation and formation treatment become easy and a long life electrode is obtained.
Claims4
A method of making a highly oxidized lead powder, containing red lead (Pb.sub.3 O.sub.4) suitable for an electrode active material of a lead battery, which comprises:
- (a) subjecting a raw lead powder consisting essentially of metallic lead and 60 to 80% by weight red litharge (.alpha.-PbO) to maturing oxidation which increases the red litharge content of the raw lead powder at least 5% to produce a matured material having a red litharge content of 80 to 90% by weight, thereby realizing a spontaneous rise in temperature, and controlling said temperature rise to below 100.degree. C. for an initial 15 to 90 minutes of said maturing oxidation, by adding cooling water to said raw lead powder in order to restrict the production of yellow litharge (.beta.-PbO);
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- (b) then heating the matured material from step (a) to a temperature of 400.degree. to 500.degree. C. to produce a red lead content of 80 to 90 weight %,
- steps (a) and (b) being successively performed within the same rotary kiln.
Dependencies are inferred from the claim text.