The hardness of positive boron carbide (B_4C) is second only to diamond, and it has the characteristics of neutron absorption, wear resistance and semiconductor electrical properties.Its main use is as cemented carbide gem grinding tools and other new materials.In order to reduce the cost, researchers are working on a new process to prepare boron carbide.In order to cooperate with the research of this new technology, it is necessary to analyze the content of elemental boron in the product.The technical condition requires that the content of elemental boron in the product should be less than 0.7%.

The purpose of this work is to find a method for separating boron elemental from large quantities of boron carbide.Since boron carbide is prepared under the condition of high temperature hydrogen reduction, there is no boron oxide in the product.1 The main reagent sodium hydroxide standard solution :O.1mol·L~(-1), prepared by conventional method, the carbonate in it was removed by barium chloride precipitation method, and the accurate concentration was calibrated by potassium hydrogen phthalate.The calculated concentration value is multiplied by 0.0108 to obtain the boron titration.Glycerin :7+1, adjusted to pH 8 with dilute sodium hydroxide solution. Glycerin can also be replaced by mannitol.2 Separation conditions for elemental boron.