The Controllable Chemical Transformation Of The Surface Layer Of Stilbite Particle

The silica is a kind of important fine inorganic product of chemical industry, assumes the tiny granule shape, the versatility. But under the earnest thorough analysis, when the silica uses to make the rubber strengthening agent, the printing ink, the coating padding, the toothpaste to rub the liniment (is called toothpaste accurately with silicon dioxide), we think it has an effect merely respectively on its surface layer, the surface layer very thin part or the edges and corners of the surface, but very major part of the interior does not play a role. According to the above, we conceive prepare one kind of granule, which has the nucleus - shell composite construction, whose interior (nucleus) is the inexpensive mineral, but the composition, the structure, the performance etc of the outer surface (shell) is similar with the silica. Such new product (we call it ASNS, amorphous silica with novel particle structure), may substitute the existing product in certain applications, and create very great economic efficiency and the social efficiency. Regarding this kind of project development, it can be imagined the difficult degree.The stilbite produced in the northern of Guilin, is rare in the world with its high purity, big reserves. In the earlier period research work, this study team discovered that the response of the stilbite and the acid is only restricted in occuring in the pellet surface layer when we control the requirement. We believed that we can obtain ASNS by making the careful transformation to the stilbite pellet surface layer. The present paper first summarizes the research results of the reaction of each kind of aluminosilicate and the acid, the full understanding possibly using the medicament type, the processing way and the condition and so on, to supply for reference. Before we research the condition systematically and deeply by prepareing ASNS with the stilbite, we propose its important technical specification, namely the measurement degree stilbite pellet surface layer transformation― surface layer conversion rate. In order to determinate this target fast and accuratly, serve well the new product development, and prepare well for the quality detection and the control (the method will be an important component of the future new product technology standard, enterprise standard), we also proposed an innovation to this kind of product's attribute method, which propose the adsorption method of probe molecule to determinate the surface conversion rate of the stilbite particle(PSTS, product of surface layer transformation of stilbite). When the surface layer conversion rate is 100%, PSTS only then has possibility been ASNS.The theoretical foundation of this thesis is that the stilbite and amorphous SiO2 adsorpt the molecular whose diameter is bigger than 0.62nm limited to occur in the outside surface, seeped very few to the inner layer. Regarding this we have studied the adsorption relations between the two particle and many kinds of dye intermolecular. According to the difference of the adsorptive capacity, we have explored a simple, fast and reliable examination method.The prime task is as follows:1 We have researched the adsorption process of amorphous SiO2 to methyl orange, methylene blue, gentian violet. The result indicated that amorphous SiO2 basic does not adsorb the methyl orange. But it adsorbs the methylene blue and the gentian violet easily for the methylene blue and the gentian violet are the positive ion dye members. It also can achieve the adsorption equilibrium rapidly about 10min, and has a big adsorptive capacity.2 We have also discussed the adsorption process of stilbite to methyl orange, methylene blue and the gentian violet under the same experimental condition. The result indicats that: the stilbite basic does not adsorb the methyl orange in the neutrality and the alkalinity condition, but adsorbs the methyl orange in the acidic condition. And the adsorptive capacity will increase when the pH increase under the acidic condition. The adsorption process of stilbite to methyl orange is a slow process, which probably needs 2h to achieve the adsorption equilibrium. The adsorptive capacity of stilbite or amorphous SiO2 to the methylene blue and the gentian violet is equivalent. Both of them adsorb greatly, but the adsorption equilibrium time is long, while the methylene blue needs 150min, the gentian violet needs 90min to be able to achieve balanced.3 The stilbite after the treatment of the hydrochloric acid and the high temperature adsorbs the methyl orange more easier than the natural stilbite. When the initial density is 20mg/L, the pH is 4.5, and the temperature is 20℃, the natural stilbite's adsorptive capacities to methyl orange is 1.43mg/L, and the pretreated stilbite's adsorptive capacity may increase to 3.48mg/L under the same condition. 4 We finally determine to take methyl orange as the probe molecule. When the temperature is 20℃, the quality of absorbent is 0.2g, the initial density of methyl orange solution is 20mg/L, and the pH is 1, the adsorptive capacity of amorphous SiO2 to methyl orange is q ' = 0, while the adsorptive capacity of Stilbite to methyl orange is q°= 2.13mg/g. Take the q ' and q°into the conversion rate formula: x = (2.13- q) / 2.13Only to need determine the adsorptive capacity q of the product PSTS under the similar condition, then we will obtain the surface conversion rate of the stilbite particles.