Product formulation

The formulation of a powder mixture plays a central role in the processing of bulk materials. It encompasses far more than just a list of ingredients and quantities. The aim is to obtain a reproducible end product with defined properties and consistent product quality. The basis for this is the complete specification of all raw materials used. Each raw material must be clearly described, including its origin, manufacturing process, age, packaging and form of delivery. The powder-related properties must also be taken into account. These include bulk density, particle size, particle size distribution, pre-treatment, dustiness, moisture content, purity, solubility and colour.

Equally important are the thermal boundary conditions. These include the storage temperature of the raw materials, the temperature of the components to be fed in, and, where applicable, the temperature of any liquids added. The climatic conditions during feeding and mixing must also be specified. Of particular importance is the temperature of the powder mixture at the end of the process, as this can have a direct influence on the product structure, homogeneity and subsequent processing steps.

A key component of the product formulation is the description of the mixing process. This includes the design of the mixer, the batch size and the timing of the mixing programme. Multi-stage or multi-step mixing processes, as well as the method of liquid addition, must also be defined. All these factors influence the homogeneity, product structure and reproducibility of the final product. The formulation also includes the definition of the discharge process. The container, container size, material and discharge method must be specified. Inerting carrier gases, handling and potential effects such as segregation or compaction after mixing must also be taken into account. Finally, preparatory measures are of central importance, such as the defined cleanliness of the mixer and its temperature prior to filling.