zinc carbide is a zinc oxide that can be used as a white pigment, or as a catalyst in the rubber industry. It also serves as an activator in some plastics.
Zinc is a common substance that occurs naturally in many foodstuffs and in drinking water. But it can also be produced from industrial sources or waste sites.
Thousands of tons of zinc-carbon batteries are discarded every year around the world, and many are not recycled. These cells are used in light-drain or intermittent-use devices, and their lifespans are usually short.
The electrolyte of a zinc-carbon battery is composed of a mixture of ammonium chloride and zinc oxide in water. This solution is absorbed by the zinc anode and the manganese dioxide cathode, creating a current.
A separator is often inserted into the zinc anode. This serves as a current collector, and it vents hydrogen gas that evolves during the reaction. It is usually tin-plated steel or brass, to help conductivity and prevent exposure of the zinc.
Most dry cells contain 0.05% cadmium (to improve the grain and make the cell harder) and 0.25% lead to increase corrosion resistance. Cadmium and lead were banned from most consumer batteries in the United States in 1990, due to their environmental concerns, but some modern batteries are made with a combination of these elements.
The zinc anode and the carbon rod form the positive electrode and negative electrode of the battery. The paste or paper, which is either a gelled substance or coated with kraft paper, physically separates the two and allows ionic conduction through the electrolyte.
