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| Being high dispersity, hydrophilic property and viscosity, bentonite is widely used in the pellet production. Hunyuan bentonite is one of large-type bentonite deposits in China, the reserve of which is more than 0.15 billion tons. However, it is a kind of typical Ca-bentonite (Ca-Bent), not completely utilized in the pellets presently. The sodium-modification of the Ca-bent is investigated by means of suspend liquid in this paper. To begin with, the process mineralogy of the sample is carried out, based on which, different factors (sodium agent and dosage, pulp density, sodium temperature and sodium time, etc.) affecting the sodium-modification are researched. The results show that the alkali coefficient K of modified bentonite is increased from 0.34 to 1.33, and the 2HWA, dilation and colloid index are respectively increased to 601%, 32.4mL/g and 87.6mL/(3g) under the optimal conditions of Na2CO3 dosage 3.0%, pulp density 20%, sodium temperature 55℃ and sodium time 0.5h. The XRD patterns of the bentonite before and after sodium-modification show the d(001) from 1.5539nm reduces to 1.2467nm, and 2θ(001) from 5.6875° increases to 7.0907°, indicating that the Hunyuan Ca-bent is effectively modified into Na-Bent. This investigation can provide a feasible route for the utilization of Hunyuan bentonite. |
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| Keywords:Ca-bentonite;Na-bentonite;sodium-modification;pellet binder |
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