What is it?
Bentonite is a kind of clay that has been discovered in Fort Benton in the United States. It can have different colors, such as white, grey, red-white, brown-white, and light yellow. Within this clay, you can find very small particles that allow bentonite to make the ground waterproof. Another property is its high viscosity. This makes bentonite resistant to deformation by shear stress. Other properties of this type of clay are rheological properties, absorption properties and a thixotropic property. The first one means that it becomes viscous in combination with water. The second one allows bentonite to absorb liquids. And the third one allows the solution to acquire the characteristics of a gel, which makes it easy to deform and move.
What is it used for?
Bentonite is widely used in civil engineering. It can be very useful as drilling fluid. In addition, it is often used on contaminated sites. Bentonite is then used to isolate the site together with a diaphragm wall. Furthermore, this type of clay is used in a litter box, because it has an absorbent effect when it comes in contact with urine. Further applications of bentonite can be found in metal foundries, wine clarification, and the improvement of sandy soils in agriculture.
Bentonite and the HDD world
In the horizontal directional drilling world bentonite is used for various reasons. It is mainly used to keep the borehole open and to transport the soil or sand from the borehole to the surface. The bentonite solution can be thick or thin. The thin solution is mainly used for sandy soils, so more sand can be transported to the beginning or end of the borehole. When drilling in gravel soils, a thicker solution is used. This looks like a kind of gel and is useful to keep the gravel in the borehole on the side, so you create a kind of solid hole. In addition, the thicker solution is used as a kind of lubricant to allow the steel tubes to slide through the soil. This is important as these rods have to pass through the ground from several hundreds of meters up to 2-3 kilometers.
At Bofram we make the mix, pump, and recycle units needed to mix the bentonite powder with water to create the right solution and apply it to the horizontal directional drillings. Our machines are completely drawn in 3D in order to make maximum use of the available installation space. For example, when the mix, pump, and recycle machine has to be placed in an HDD drilling vehicle. By using a well-thought-out mix of techniques and an optimal design of the tanks, a bentonite solution can be mixed in a short period of time. You can then quickly and efficiently start executing horizontal directional drilling.
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