Trisodium phosphate (TSP) has several major uses in various industries and applications, including:

1. Cleaning Agent: TSP is widely used as a powerful cleaning agent in industrial and commercial settings due to its ability to remove grease, grime, and stains from surfaces. It is commonly used to clean surfaces before painting or refinishing, as it can effectively remove dirt and old paint residue.
2. Food Additive: TSP is used as a food additive in some countries to enhance the color, texture, and flavor of processed foods. It is also used as an acidity regulator and sequestrant in some foods, such as cheese, processed meat, and canned soups.
3. Water Treatment: TSP is used as a water treatment chemical in municipal and industrial water systems to prevent scale formation and control corrosion. It is also used in swimming pools and spas to maintain the proper pH level and alkalinity of the water.
4. Metallurgy: TSP is used in metallurgical processes as a fluxing agent to remove impurities from metals and alloys during smelting, refining, and welding operations.
5. Agriculture: TSP is used in agriculture as a fertilizer and soil amendment to provide phosphorus, an essential nutrient for plant growth. It is also used as a feed additive for livestock to supplement their phosphorus intake.

However, it is important to note that TSP can be harmful if not handled properly, and it is recommended to use it in a well-ventilated area and wear protective clothing, gloves, and eyewear.