一、物理方法物理方法是利用被提纯物质和杂质之间物理性质的差异而除去杂质的方法,一般可分为过滤和结晶两种.1.过滤法此法是把难溶性物质跟易溶性物质分离的一种方法.例1如何除去食盐中混有的少量泥沙?简析将含有泥沙的食盐溶于水,利用食盐溶于水而泥沙不溶的特点,通过过滤即 First, the physical method Physical method is to use the difference between the physical properties of impurities and impurities and purification methods, generally can be divided into two kinds of filtration and crystallization. 1. Filtration method This method is to insoluble substances and soluble substances A method of separation. Example 1 How to remove a small amount of sediment mixed with salt? Concise analysis Dissolve salt containing sediment in water, use salt to dissolve in water and insoluble in sediment, through filtration