Trends in Particle Size Analysis Quality Control in the Fertiliser Industry with Dynamic Image Analysis

摘要

Particle size analysis is an important step in the quality control of many industrial production processes. This article describes the implementation of Dynamic Image Analysis (DIA) in the fertiliser industry as a typical example. DIA is used in the same way in other industries, for example for pharmaceuticals, foodstuff, plastics, chemicals, metal powders and even granulated explosives. Fertilisers are typically dried bulk materials, which enhance the supply of nutrients for cultivated plants. The most important components of a fertiliser are nitrogen, phosphate and potassium, as a lack of these elements in the soil limits plant growth. Many fertiliser producers combine these elements in order to improve the soil in a controlled and systematic way. Fertilisers are usually produced in a granulated form to optimise handling, dosage and controlled release of the nutrients. Manufacturers use two special terms to characterise the particle size of their products. The average particle size is called SGN, Size Guide Number, and the width of the size range is called UI, Uniformity Index. Both numbers are closely monitored for each fertiliser batch, as they influence not only the dissolution and release on the field, but also the blending of different minerals and the segregation during transport. Another critical aspect is the amount of dust generated both during production and in the final product. Dust particles can be absorbed through inhalation or through the skin by the workers in production or during loading/unloading which may cause health issues.