In this paper some methods of chemical decomposition in the recycling of different kinds of waste plastics have been reviewed,and the advantages and shortcomings between supercritical and conventional decomposition methods are also discussed and compared herein.

To achieve both qualitative and quantitative understanding of the chemical decomposition characteristics of hardened cement paste (HCP) subjected to the elevated temperatures of fire,X-ray diffraction (XRD) is adopted on HCP samples after their exposure to various peak temperatures from 400 to 800 ℃ so as to test their C-S-H chemical decomposition dynamics.

By adding prescreening before secondary crusher,the technical transformation of crushing technology was done in Sanshimudi concentrator.

The original mineral of Dading Iron Mine was processed by the technique which in- cluded pre-classification, dry magnetic separation to discard dirt, magnetic separation of the coarsely ground ore, scondary grinding and secondary magntic separation of the rougher con- centrate, thus raising the processing quantity of the crude ore, reducing the grinding cost, with the grade of iron concentrate 65.