Research on Fluorine release of coal and clay used by residents in Zhaotong Fluorosis areas,Yunnan Province

The Fluorine release rate of coal, clay of different Fluorine content, and coalmixed with clay used by resident households were studied by using the ion selective electrode(ISE) and solidoid balance methods, and the degree of influence on Fluorine pollutiongenerated by coal and clay was analyzed according to the proportion characteristicsof coal used by resident households.The results show that the Fluorine release rate ofcoal is more than 95% during combustion; The Fluorine release rate of clay is more than99%; The Fluorine release rate of coal mixed with clay is between 56.44% and 96.64%,and the average value is 76.68%.The clay as a binder for fine coal is one importantsource of Fluorine pollution caused by coal-combustion in Zhaotong, Yunnan Province.When the Fluorine content of coal is less than 80 mg/kg, the Fluorine amount releasedfrom clay (in which Fluorine content is more than 530 mg/kg) is more than 50% of the totalFluorine amount released from coal and clay during coal-combustion.The Fluorineamount released from clay (in which Fluorine content is more than 1 000 mg/kg) is morethan 70% of total Fluorine amount released from coal and clay during coal-combustion.

The Fluorine release rate of coal, clay of different Fluorine content, and coal mixed with clay used by resident households were studied by using the ion selective electrode （ISE） and solidoid balance methods, and the degree of influence on Fluorine pollu- tion generated by coal and clay was analyzed according to the proportion characteristics of coal used by resident households. The results show that the Fluorine release rate of coal is more than 95% during combustion; The Fluorine release rate of clay is more than 99%; The Fluorine release rate of coal mixed with clay is between 56.44% and 96.64%, and the average value is 76.68%. The clay as a binder for fine coal is one important source of Fluorine pollution caused by coal-combustion in Zhaotong, Yunnan Province. When the Fluorine content of coal is less than 80 mg/kg, the F[uodne amount released from clay （in which Fluorine content is more than 530 mg/kg） is more than 50% of the total Fluorine amount released from coal and clay during coal-combustion. The Fluorine amount released from clay （in which Fluorine content is more than 1 000 mg/kg） is more than 70% of total Fluorine amount released from coal and clay during coal-combustion.