The yield of M reached 25.5% and the product quality could meet the standard of HGB2 157 61. The method was characterised by reliable technology, reasonable process flow, stable and easy operation.

• 试验结果表明，M 的得率达25.；5%25 ，产品质量达到HGB2?157?61标准。 该方法技术可行，工艺流程合理，操作稳定、简便。