Course:SPPH381B/TermProject/Alkaline battery- Samin/Granulation

Introduction

The principle involved in compaction is simple: a steel punch descends into a cavity and compacts the mixture. As it retracts, a punch from below rises to eject the compacted preform.

In an alkaline battery, the cathode actually doubles as part of the container. Huge loads of the constituent ingredients—manganese dioxide, carbon black (graphite), and an electrolyte (potassium hydroxide in solution)—are delivered by train and mixed in very large batches at the production site. The mixture is then granulated and pressed or compacted into hollow cylinders called preforms. Depending on the size of the battery being made, several preforms may be stacked one on top of another in a battery. Alternatively, the series of preforms can be replaced by an extruded ring of the same material.

The preforms are next inserted into a nickel-plated steel can; the combination of the preforms and the steel can make up the cathode of the battery. In a large operation, the cans are made at the battery factory using standard cutting and forming techniques. An indentation is made near the top of the can, and an asphalt or epoxy sealant is placed above the indentation to protect against leakage.

List of Hazards

Physical hazards

1. Cuts and scrapes of skin (due to machines used in this process).

2. Loud noise caused by heavy machinery.

Chemcial hazards

1. Burns to eye and skin (exposure to potassium hydroxide)

2. Exposure to asphalt or epoxy (skin irritant compounds which may cause allergic dermatitis and other skin disorders including abrasions)

Biological hazards

1. Respiratory diseases-bronchitis, pneumonitis (exposure to manganese dioxide)

2. Graphite pneumoconiosis

Psychological hazards

1. Neurobehavioral dysfunctions, called Chronic manganese poisoning or manganism