Hobart cement mixer

Bricks were made from this mud by dye casting. To that end, 250 g of sand and 250 g of wet red mud were added to 30 wt% water and mixed for 10 min in a Hobart cement mixer. To this mixture, 62.5 g of 85 wt% concentrated H3PO4 solution was added and mixed for another 5 min when the pH of the solution became 3.11. At this point, 1 g of reagent grade Fe was added, and the slurry was mixed for 25 min it formed a thick mass, which was then pressed at 1000 psi (7 MPa) in a brick mold of size 8 X 4 X 2.5 in. (20 X 10 X 6 cm ). The resulting brick was cured in a closed container at room temperature it hardened sufficiently after one day. 

Dry mixing— where the fibers are initially mixed with a fine dry aggregate (5 mm), then cement and silica fume added, followed by mixing in a Hobart industrial mixer for about 5 min. The mixing was completed in a concrete mixer to which the coarse gravel aggregate (25 mm) was added [9]. The silica fume helps the dispersion of the carbon fiber and reduces the porosity of the concrete, resulting in an improved bond. 

An automatic/manual mortar mixer Hobart model N° 50 was utilized. The cement was mixed with water that was poured into the mixing bowl after adding the cement. The ratio of water to dry cement, as received, was 0.45 by weight. The water was carefully added and the paste was mixed on the mixing blade. 

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