Method for determining content of free calcium oxide in steel slag

The invention discloses a method for determining the content of free calcium oxide in steel slag. The method comprises the following steps: 1, carrying out heating decomposition of a steel slag sample in inert atmosphere, and using a weight loss caused by the water volatilization during the heating decomposition of the slag sample to calculate the content of Ca(OH)2; 2, determining the content of free total calcium in the steel slag sample subjected to the heating decomposition; and 3, subtracting the Ca(OH)2 content by the amount of the free total calcium to obtain the content of the free calcium oxide. The determination utilizing a principle that calcium oxide can be generated after heating Ca(OH)2 is characterized in that a water evaporation weight loss method is used to calculate the content of calcium hydroxide (Ca(OH)2), a simple easy-implementation determining method is used to determine the amount of free total calcium, and finally an accurate free calcium oxide value is obtained. The determination me