Milled products such as limestone, concrete, calcium oxide are the base of the minerals industry. Those products are used in construction, chemistry, metallurgy, or even agriculture but often, those powders are highly cohesive and additives are commonly used to enhance their flowability. Lear more about our Granutools can help you choose an additive and dose it in order for your powder to be used in new applications.
We show how the GranuDrum instrument can be used to quantify the effect of flow enhancer additives. The main forces inducing cohesiveness in powders are van der Walls force (always present at the contact between two solids), capillary force (related to the water content), electrostatic force. Therefore, the apparition of powder electrostatic charges inside it due to the triboelectric effect can increase powder cohesiveness.
The next graph shows the evolution of the calcium oxide cohesive index as a function of the fraction of additive. The cohesive index is measured with the GranuDrum at a rotating speed of 20RPM. A strong decrease in cohesiveness is observed after the addition of a small quantity of additive. If more additive is added, the cohesiveness is stable before a significant increase in the cohesiveness.
The GranuDrum flowmeter is able to determine the optimal quantity of flow-enhancer additive for limestone and the derivative products.
