The effect of doped ions on the formation and stability of C₁₁A₇·CaF₂ at high temperature was investigated. The results show that the effect of doped ions on the formation and stability of C11A7·CaF2 is depended on the kind and amount of doped ions. The melting point and formed amount of C₁₁A₇·CaF₂ is decreased when Fe₂O₃ or MgO is doped. With the addition of BaO the formed amount of C₁₁A₇·CaF₂ is also reduced due to the decrease of aluminum content available for the formation of C₁₁A₇·CaF₂ due to the reaction between BaO and aluminum oxide. The addition of ZnO can effectively promote the decrease of free CaO content in the reaction system and has no visible influence on the formed amount of C₁₁A₇·CaF₂. Most of doped ZnO exist in the form of free ZnO only with a little being combined with C₁₁A₇·CaF₂ to form solid solution.

Fly ash produced from MSW incineration  is judged as dangerous rubbish as it abound in heavy metal and various poisonous and deleterious material. Comprehensive research is carried out all over the world to study how to beneficially utilize this waste. This essay gives an introduction about the current processing method and takes it as a beneficial utilization to put fly ash into cement kiln; meanwhile, it indicates that we should exploit a processing technology on how to utilize such fly ash according to the situation of China.

The principle of cepstrum analysis was introduced and a method of gear box fault diagnosis based on cepstrum analysis was presented. Considering the problems that  more modulation sources and too complicated frequency in vibration signal, the cepstrum analysis method was applied to remove these problems. Test results show that cepstrum analysis for fault diagnosis of ball mill gear box had many merits.

Spot testing and analysis is performed on the violent vibration and noise of a gear box  on a large  cement ball mill. The chief fault and reasons are found out. The suggestions for mending gear box are recognized by the user.