Contact angle of water on iron ore fines: Measurement and analysis

Abstract

The relative contact angle (?RCA) for seven iron ore fines was measured by using Washburn Osmotic Pressure method under laboratory conditions. By choosing cyclohexane as the reference that can perfectly wet iron ore particles, the relative contact angles were measured and varied from 57? to 73?. With the volume % of goethite (?G) as the variable, a new model for relative contact angle was developed. The expected relative contact angle for pure goethite is about 56?, while that for goethite free samples is about 77?. Physical properties, such as surface morphology (SMI) and pore volume (Vpore) can influence the relative contact angle. The ?G can be expressed as a function of SMI and VPore. Thus, we inferred that the relative contact angle is a function of ?G for the iron ores used. The measured relative contact angles were found to be in good agreement (Radj 2 >0.97) with the calculated ones based on the research from Iveson, et al. (2004). Comparing with the model developed by Iveson et al.(2004), the new model for contact angle proposed in this paper is similar, but more detailed with two meaningful physical parameters. The modification of physicochemical properties on iron ores would be another topic in the further study on granulation.

Measurement for Contact Angle of Iron Ore Particles and Water

“…There's a strong relation between water contact angle and the ratio of goethite and hematite from the results of Huang and Iveson. [48][49][50] Unfortunately, content of these chemical compositions didn't be obtained by other authors to support this opinion.…”

“…92) In the experiment of Iveson, ore compositions were determined using a manual point counting technique on a polished surface of each ore. 48) Both Iveson and Huang obtained the true density of samples by volumetric displacement of cyclohexane in a 25 ml flask. [48][49][50] S BET is the specific surface area represents the specific area of the internal and external surfaces was measured by nitrogen adsorption method. 50) The specific surface area of goethite concentrate was determined based on BET method.…”

“…[48][49][50] S BET is the specific surface area represents the specific area of the internal and external surfaces was measured by nitrogen adsorption method. 50) The specific surface area of goethite concentrate was determined based on BET method. 101) Surface morphology of iron ore particles are also studied by using SEM.…”

“…Huang et al 50) used the difference between the two surface areas to describe the surface morphology index (SMI) and defined SMI = S BET /S LPSA . 106 With the calculated composition of each oxide, they also found a relationship between measured density and calculated goethite content which is show in Fig.…”

“…Iveson et al 48,49) have done a series work on the contact angle of iron ore fines, include measure the value of advancing contact angle of 17 different iron ores. Huang et al 50) tested contact angles of 7 kinds of iron ore particles with water and proposed a new model for contact angle.…”