As cement retarder, the effect of desulphurize ash and dregs coming from power plant using fuel oil (DADFO) was studied here． The result shows that anhydrous calcium sulphate, calcium oxide and calcium carbonate are contained mainly in DADFO． When only use DADFO as retarder, the setting time will be obviously reduced, but if use DADFO together with desulfur gypsum, the setting time and strength are less change, and has good compatibility with water reducer． DADFO and desulfur gypsum are mixed as cement retarder in Portland cement, both strength and other properties are improved．

The influence of different fineness and different addition of super－fine slag on the performance of cement are studied． It is technically feasible that clinker and slag can be separate ground first and then ground together． The optimal addition of SO3 in cement and the composition of high content slag is determined． It is possible to produce high quality cement by using super－fine and high content slag mixed with clinker and gypsum．

The effect of grinding aids on slag grinding performance is studied in the paper． Put different grinding aids in slag mill under same grinding condition, then take tests on specific surface area with the intervals of 0.5h． Compare the surface areas with that of slag without using grinding aids and analysis the samples by image analyzer and SEM． Furthermore, water requirement of normal consistency, setting time and strength were tested． The results shows that the grinding efficiency of this compound grinding aids play no harm to slag cement performance, but can enhance mortar strength． The proper amount of compound grinding aids used in slag is 0.04％～0.08％ of slag weight, and the grinding time should be more than 1.5h．

The concept and properties of persistent organic pollutants are introduced. For their treatment,some typical thermal destruction technologies are illustrated in details, and the related process's mechanisms and research progresses are concluded. The suggestions for the treatment of the POPs in the future are also given.