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Lead powder is a mixture of 60% ~ 80% lead oxide and 20% ~ 40% lead. It is one of the main raw materials used to manufacture active substances of electrode plates. The quality of lead powder has a great influence on the manufacturing of lead paste, the process parameters of plate formation and the electrical performance of battery. Lead powder has scales, petals and clusters.
Quality index of lead powder. The quality indexes of lead powder include the oxidation degree, apparent density, water absorption, dispersion and structure of lead powder, of which the apparent density and oxidation degree are the main. The oxidation degree is the percentage of lead oxide content in lead powder, indicating the composition relationship between lead oxide and lead. The smaller the particle of lead powder, the higher the oxidation degree, and the oxidation degree is a factor affecting the porosity of the plate. The increase of oxidation degree will increase the initial capacity of the battery, on the contrary, the initial capacity will decrease. However, if the oxidation degree is too high, the negative plate will crack due to large volume shrinkage during drying, and the positive active material is easy to fall off during the charging and discharging cycle, so as to shorten the service life of the battery. The oxidation degree of lead powder is generally controlled at 60% ~ 80%. The apparent density of lead powder is the apparent density naturally accumulated by lead powder particles, expressed in g / cm3. It is a comprehensive index of lead powder thickness and oxidation degree. In production, the apparent density is generally controlled as 1.8 ~ 2.1g/cm3. The porosity of lead powder can be calculated from the apparent density of lead powder. The water absorption of lead powder is the amount of water absorbed by a certain amount of lead powder, usually expressed in percentage. It shows the water absorption capacity of lead powder in the process of mixing paste. The water absorption of lead powder is related to the oxidation degree and particle size of lead powder.
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