Statistical Analysis of Wear Rate of Phosphate-Grinding Mill, November 2004

• Published in: Corrosion (Houston, Tex.) Tex.), 2004-11, Vol.60 (11)
• Main Authors: Tao, D., Chen, G.L., Parekh, B.K.
• Format: Article
• Language: English
• ISSN: 0010-9312; 1938-159X

ABSTRACTThe United States is the largest phosphate rock producer in the world. About 30% of the world's production is produced by the United States.1 The state of Florida accounts for approximately 80% of U.S. phosphate production.2 A typical phosphate beneficiation process in central Florida includes washing, classification, fatty acid flotation, acid scrubbing, and amine flotation. The upgraded phosphate concentrate is used for toothpaste, detergents, food, fertilizers, etc. Approximately 95% of produced phosphate is consumed in fertilizer plants where phosphorus, together with nitrogen and potassium, is utilized as the major nutrient for plants. In fertilizer plants, phosphate is used to produce phosphoric acid by reacting phosphate with sulfuric acid. The phosphogypsum crystals formed during this chemical reaction are discarded, and the phosphoric acid is further processed to form the finished fertilizer product. To increase the chemical reaction rate, phosphate rock is ground to fine particle sizes prior to the chemical reaction process. It usually takes 10 min to 15 min of grinding to reduce the phosphate size to more than 40% ­200 mesh. The direct operating costs in grinding are mainly the energy consumed and the metal lost through wear and corrosion.3-4 Fine grinding of phosphate is energy intensive, and more than 60% of the electrical energy consumed in the phosphate fertilizer plant is used in grinding phosphate rock. Thousands of tons of grinding media are consumed in phosphate chemical plants every year, and reduced wear and corrosion rates will significantly reduce the grinding costs and improve the grinding efficiency by maintaining optimal grinding ball size. Previous efforts to reduce grinding media consumption were mainly on finding the most wearresistant metal, e.g., high-chromium alloys, and sig-