Yanshan Bentonite Purified And Modified Modified

In this paper, the primary bentonite which is from Yanshan county in Yunnan province was purified and re-modified. Using orthogonal table, both the montmorillonite content and methylene blue test as evaluated index, the better and low-cost modified sodium salt have been filtrated and the best process conditions are obtained. Three kinds of quaternary ammonium organobentonites have been synthesized by using the sodium-bentonite and three quaternary ammonium halides which are DTAC, CTAB and the mixture of them respectively. The best process conditions were obtained in this part and using the properties of organic compoundas evaluated index. The structures of three kinds of organobentonites have been characterated by X-ray diffraction and infrared absorption spectrum. And then put the ammonium organobentonites as a kind of anti-sedimentation agents into coating. The effect of organobentonite for the thixotropy and sedimentation ratio in coating have been studied. The researches showed that:1. The average quantity of montmorillonite content in specimens which were purified by the best process conditions was from 67.51% before purified to 97.02%.2. The specimens were made under the same process condition using NaF, NaCl, Na₃PO₄ Na₂CO₃, NaOH and Na₄P₂O₇ respectively. The result showed that the modified effect of NaF is the best. The four physical capability were: expanding content is 93.37mL/g; colloid content is 34.70mL/g; absorption of methylene blue is 1.403mmol/g and CEC is 1.3911mmol/g.3. The best process conditions in organic modification were: (1)The dosage of DTAC is2.50mmol/g bentonite; Reactive temperature is 80℃; The dosage of water is 600mL; Reactive time is 1.5h. (2)The dosage of CTAB isl.50mmol/g bentonite; The pH is 9; Reactive temperature is 60℃; The dosage of water is 550mL; Reactive time is 1.5h. (3) The ratio of mixture is1: 3; The pH is 9; Reactive temperature is 80℃; The dosage of water is 550mL; Reactive time is 1.5h.The specimens were made by using the best process condition. The figure of space between layers showed that DTAC organobentonite is 1.8967nm; CTAB organobentonite is 2.3011nm; and mixture organobentonite is 2.4592nm.4. Putting the mixture organobentonite into coating, the sedimentation ratio of coating dropped evidently when the dosage of under 2.5%; the thixotropic index was 1.49 when the dosage was2.5%. The best dosage of mixture organobentonite in coating was 1.5%-2.5%.