Field experiment for blasting crater

A series of single hole blasting crater experiments and a variable distance multi-hole simultaneous blasting experiment was carried in the Yunfu Troilite Mine,according to the Livingston blasting crater theory.We introduce in detail,our methodology of data collection and processing from our experiments.Based on the burying depth of the explosives,the blasting crater volume was fitted by the method of least squares and the characteristic curve of the blasting crater was obtained using the MATLAB soft- ware.From this third degree polynomial,we have derived the optimal burying depth,the critical burying depth and the optimal explosive specific charge of the blasting crater.

Physical chemistry mechanisms of CDR system in sulphide mineral flotation

The flotation tests, zeta potential measurements, and Fourier transform infrared spectroscopy （FTIR） analysis on galena, sphalerite, and pyrite were studied in a collecting-depressing-reactivating （CDR） system. In this system, sulphide minerals were first collected and acti- vated by the collector, and then depressed strongly by Ca（OH）2 in a strong alkaline solution. Finally, they were reactivated by H2SO4. The flotation tests of pure minerals showed that in the Ca（OH）2 depressing process sulphide minerals had similar flotation characteristics because they had already been influenced by the collector. Hence, the flotability differences between them were reduced. However, in the H2SO4 re- activating process considerable differences in the flotability between galena and sphalerite/pyrite were produced. That is to say, galena was relatively easy to be reactivated by H2SO4, but sphalerite and pyrite were not reactivated at pH 〉 11. The zeta potentials of sulfide minerals measured by the Zeta Plus presented irreversible characteristics on the change of pH values. The results of the FTIR spectra analysis indi- cated that the collectors already adsorbed on the mineral surface were removed partially by Ca（OH）〉