Topic: Experimental assessment and quantification of segregation by means of hopper segregation, sifting segregation and vibration segregation set-ups.
Determining the amount of segregation using analytical measurement methods
Blending on itself is a challenging process and a lot of parameters need to be finely tuned in order to obtain a high-quality, homogeneous product. The same parameters that make blending difficult, allow for segregation to occur. Segregation occurs when motion is put into a (blended) product, allowing particles to separate from each other. There are several mechanisms that may cause segregation and it is important to understand which mechanism can or may cause de-mixing in a process.
Delft Solids Solutions has three analytical set-ups available, each of them to simulate a different unit operation and to induce possible segregation, all employing a different segregation mechanism. A sifting, fluidization, or vibrational segregation mechanism can be induced by these set-ups. The extent of segregation can be quantified by identifying differences in particle size, particle shape, density and chemical composition of certain fractions extracted from the measurements. Based on various case studies, the extent of segregation of the three different research set-ups is shown.
As a recommendation some possible solutions to prevent segregation are provided, although it will need to be considered that alterations to a product may lead to unwanted changes in other bulk parameters, like e.g. the flow ability and caking tendency of the product.
Summary: In this contribution we demonstrate the application of such set-ups for identifying the segregation potential of powder blends based on differences in particle size and density. To that end, we also use an algorithm to quantify the segregation in each of the set-ups allowing a fair comparison among the various set-ups but also among different formulations.
Patrick Verolme studied Chemistry in Rotterdam and received his Bachelor of Science degree from the Rotterdam Hogeschool, after performing his graduation study at Delft Solids Solutions on the topic of water vapor sorption studies. Since 2012 Patrick has been working at Delft Solids Solutions in the field of solid particle / powder research, with his main area of expertise being specific surface area, porosity and vapor sorption studies. His role has expended to the research of bulk powder characteristics, including segregation, dustiness potential, stickiness and attrition & abrasion of solid materials. He is a frequent speaker on these bulk solids topics on seminars and courses.