Active lime application metallurgical lime prices and accelerate the speed of smelting slag, shorten the refining time, reduce the consumption of lime reduces the impurities into, greatly improving the quality metallurgical activity of lime quote molten steel to the enterprise significant overall efficiency in the steel industry have formed a consensus. Active lime not only affects the steel smelting process, but also directly affect the final quality of the molten steel. Characteristics of the active lime: test method for the degree of activity. Take 50g sample metallurgical lime, and water mix into a saturated solution after adding phenolphthalein reagent pink, then the concentration of 4N (mol) HCl (hydrochloric acid) at ambient temperature 40 ℃ ± 1 ℃ of high-quality metallurgical activity lime, continuous 10min (minutes) titration, and after thoroughly number dropped HCl (titration value) ml is the "activity of" value. Amount of hydrochloric acid was dissolved, the higher the degree of activity, the better the quality of lime.