External Factors Affecting Determination of Mineral Powder Contact Angle with Capillary Rise Method

Abstract

The difficulty of standardizing the test conditions for the contact angle (CA) of a mineral powder (MP) leads to results with poor repeatability. To solve this issue, external factors that influence the CA test of a MP were investigated, and methods for controlling these factors are proposed. According to the test results, the compactness of the powder column impacts the discreteness of the MP CA remarkably in such a way that more stable compactness results in a more discrete CA. Furthermore, the number of layers and height of filter papers wrapped around the bottom of the glass tube and the selection of liquids with known surface-energy parameters impact the CA measurement of the MP directly, particularly for MPs with larger grains. More layers of wrapped filter paper are needed when MPs with larger grains are tested. The top of the filter papers wrapped around the bottom of the glass tube must be higher than the liquid level. Polar liquids with zero dispersive component of the surface-energy parameter should be selected to test MPs with larger grains.