| This article introduce the new craft that prepared cryolite from fluosilicic acid-a by-product of a phosphate fertilizer factory, ammonium hydrocarbonate as ammonia agent. Through the single factor experiment and the orthogonal experiment, some factors such as initial density of silicofluoric acid , ingredient ratio, reaction temperature, reaction time and so on influence the ammonium fluoride density and obtain the best reaction conditions to get the ammonium fluoride density and the yield of the carbon white, through the single factor analytic method, the orthogonal experiment had determined the response solution pH value, the ingredient ratio ,the reaction temperature, the reaction time .filling rate and so on the influence on the oilabsorption and the specific surface area of the carbon white; and obtained the best craft condition to prepare the good quality and high output of the carbon white. More over, to discuss the influence to the reaction rate, determined the first step of reaction is controlled by chemical reaction and infers its dynamics model.With the second step, cryolite is manufactured through the reaction of the ammonium fluoride solution and the sodium sulfate and the aluminum sulfate. The experiment study those factors such as ammonium fluoride density, reaction temperature, reaction time and so on to the content influence to the fluorine and the aluminum in the cryolite. Through the orthogonal experiment, get the most suitable craft conditions about preparation of the high yield of the cryolite. At the same time, this article has also discussed the stirring rate, filling seed crystal and the pH value of the reaction solution and so on to the influence of crystallization pellet size of the cryolite, has provided the certain advisory opinion for synthesizing the cryolite of easy to filter and big size pellet. Finally through vacuum evaporation and filter, the agricultural ammonium sulfate is obtained. With the scanning electricity mirror(SEM),the specific surface area test, X-beam diffraction meter and so on, the product performance carries on the attribute. The analysis test result has indicated that those products including the cryolite conformed to the national related standard. |
