Bentonite viscosity

USE

Bentonite clay is an addictive rheological "thickener" for many products, such as paints and drilling muds.

TEST EQUIPMENT

Spring torque: LV

Pin: Helipath TF

Speed: 5 rpm

TEST METHOD

The concentration of 10 % by weight clay in solution was created with distilled water and tested. The mixture was tested in a 600 ml Griffin low form beaker at room temperature, about 23 ° C. A Helipath holder was used with the TF minor axis due to the high viscosity and "pasty" nature of the sample. The helipath tests for "fresh" material as it rotates the T-bar axis down through the sample. This can be of great benefit when testing materials whose structure breaks down and takes a long time to rebuild.

Rheocalc software controlled the Brookfield DV2T viscometer. The data from this test is shown in Figure 1.

Figure 1

The spindle “drills” into the sample for 0 to 156 seconds. There is a noticeable decrease in viscosity after 156 seconds, as the spindle changes direction and goes up through the previously tested clay. A notable aspect of the graph is that it shows the stratification of the clay mixture. From 25 to 50 seconds, the viscosity remains fairly constant, then it gradually increases as the spindle goes down.