| The silica sand of Hucksan, Chaun and Bigum islands were tested by chemical and sieve analysis. And also their green compressive strength and permeability having different combination of clay and water with one per cent of real were studied. The results of the experiment are summarized as follows: 1. The purity and grain distribution of all sand are good, but they are not suitable for a molding sand of large steel castings because of their fineness of grain size. 2. As shown in the tables 3, 4 and 5, green compressive strength of their clay-silica sand is best at 4 per cent of temper water. 3. As the clay content increases, green permeability decreases, but at the same clay content the permeability increases with temper water. 4. The purity, refractoriness, fineness and distribution of Hucksan and Chaun islands sands are suitable for the molding sand of the shell molding process and the CO₂process. |
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