Abstract: Purification of Ca(OH)₂ is the key phase in limestone production from Carbide slag, in which the structure and operating parameters of compound hydrocyclone, as well as the physical parameters of the particles directly determine the purification effect during the compound hydrocyclone based Carbide slag classification. The internal flow field in the compound hydrocyclone is numerically simulated on the basis of RSM model and mixture multi-phase flow model, and a cut size prediction model is firstly established by using the equilibrium orbital theory. Then, the structural parameters of the compound hydrocyclone can be optimized, according to the influence of the revolving blades on the flow field and the distribution of the Carbide slag particles. After that, a prototype is built by using quadratic rotation-orthogonal combination design. According to five separate indicators involving cut size, separation efficiency, split ratio, separation precision and production volume, the separation performance and the optimal operating parameters can therefore be verified. Test results show that an optimal synthesized separation performance occurs when the inlet velocity is 2.1 m/s, the blades speed is 1 205 r/min and the inlet concentration is 22%. Specifically, the optimal performance corresponds to a cut size of 70 μm, a separation efficiency of 81.3% and a production volume of 406.7 kg/h. Numerical simulation results indicate that the pressure loss and the centrifugal force strength of the compound hydrocyclone have striking advantages while the retention time of the particles is in a weak position.

Key words: carbide slag, orthogonal test, separation and classification, hydrocyclone