Preliminary treatment of pulp by ultrasound for cleaning of ore grains and disintegration of flocculation formations based on the effects of cavitation
DOI:
https://doi.org/10.33216/1998-7927-2022-271-1-24-35Keywords:
ultrasound, cavitation, iron ore pulp, disintegration, flocculationAbstract
The research is aimed to increase the quality of processing of magnetite concentrates in flotation technological process by disintegration of ore flocculations and cleaning the surface of ore particles Applying nonlinear effects of the high-energy ultrasound field on ore particles was proposed and the peculiarities of the formation of cavitation regimes in iron ore pulp for disintegration of ore flocculations and cleaning of the surface of ore particles were investigated. The parameters of ultrasonic influence for the formation and maintenance of cavitation processes and acoustic flows in the iron ore pulp are calculated in the basis of the generalized model of the dynamics of air bubbles, presented in the form of the Rayleigh-Plesset equation.
Depending on the parameters of iron ore pulp components the optimal frequency of high-energy ultrasound to maintain cavitation processes was determined on the basis of the obtained laws of cavitation processes. Mathematical model of the process of ultrasonic signal propagation in liquid medium under conditions of changes in the speed of sound propagation and density changes was synthesized on the basis of the k-space method of the first and second order as a system of linear equations of the first order. The calculation of the power of high-energy ultrasound, which allows to maintain cavitation regimes in the iron ore pulp, was carried out on the basis of the results of the study of the propagation of the ultrasonic pulse front using computer simulations. Based on the simulation results, it was found that to improve the quality of cleaning ore particles before flotation, it is advisable to exert a spatial effect on iron ore pulp, which includes a combination of high-energy ultrasound with a specific frequency in cavitation mode modulated by high-frequency pulses and a pulsed magnetic field of decreasing voltage. In the study of the process of flocculation and deflocculation, the dependence of the value of the magnetic susceptibility of ore particles on the duration of magnetization was taken into account. The results of experimental studies of the device for demagnetization of iron ore pulp particles usage, obtained using an ultrasonic granulometer "Pulsar".
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