MATLAB在氟硅酸钠干法间歇结晶过程中优化模拟的应用

Application of the MATLAB in optimized simulation of the dry-salt and batch crystallization of sodium hex fluorosilicate

氟硅酸钠是磷复肥行业的一种重要的化工副产品,干法制取时是将氯化钠(或硫酸钠)固体盐加入氟硅酸(8～10%)中进行反应,氟硅酸钠呈结晶型沉淀而析出;在此过程中,加盐速度是影响粒度大小的关键因素,以前主要凭经验操作、可靠性差,结晶粒度细小,造成离心脱水时浪费大、产率低。本文根据结晶原理,对加盐过程进行计算机模拟,运用MATLAB编程、循环计算并解出了135个一元三次线性方程,得到了结晶过程中保证氟硅酸钠过饱和度处于介稳区的动态加盐曲线。按此曲线控制加盐速度,同等条件下,使得氟硅酸钠结晶粒度较大,产品收率提高。计算机的模拟运用和便捷计算,可为此类反应型结晶物质的制取过程提供科学的指导,为自动化精确操作打下了基础,是科研和生产中强有力的手段和工具。

Sodium hex fluorosilicate is one of the important byproducts of the manufacture of phosphate fertilizers. By dry-salt method, it is taken from the reaction between the sodium chloride （or sodium sulfate） in solid sah and fluordsilicate acid（8 - 10% ） as the crystal precipitation to separate out. In this process, adding-salt speed is one of crucial factor which affects particle size of production. At present, operation by experimental work with lacking reliability leads to the tiny crystallization granularity, more waste and low production rate when the centrifugal dehydration. According to the crystal principle, this article tries to carry on the adding-salt process by computer simulation, using the MATLAB programming into calculated circulation and has solved 135 first cubic equations, has obtained the dynamic adding-salt curve to guarantee the sodium fluosilicate degree of supersaturation in the metastable amone the crystallization process. Controlling by the curve, under the same level condition, the sodium fluosilicate crystal granularity is big, and the product yield enhanced. The computer＇s simulation utilization and convenient computation, may offer the science instruction to the process for this type of reaction crystallization material system, has built the foundation for the automated precise operation, and has been the powerful method and the tool in the scientific research and the production.