Preparation of Tuff in the Dumps of Basalt Quarries for Vibration Screening

Abstract

The article presents the current development of an integrated technology for the processing of tuff in the dumps of basalt pits to highlight the valuable metal fraction and silicate masses. In order to prepare tuff for processing, it is proposed to use the effect of moisture absorption and reduce the strength of tuff when moistened with water, since it has a porous structure and is relatively easy to absorb moisture. This operation, followed by vibratory screening in a small class of -2.5 + 2.0 mm, is promising for the selective extraction of tuff from dumps of basalt quarries, where, unlike other rocks, tuff is a water-absorbing mineral. The article presents the results of experimental studies and the development of mathematical models of the process of softening tuff with water. The objective of the research was to determine the degree of change in the strength of tuff under the influence of moisture and to establish the dependence of humidity and strength to predict the process of softening of tuff when wet. Experimental studies were carried out on various samples of tuffs of the Rafalovsky basalt quarry, while the exposure time of the sample in water was recorded, humidity, indenter indentation pressure on the press or contact load and compressive strength or contact stress during indenter penetration were determined. It was found that when moistening tuff during the day, humidity increases on average by 9%, strength decreases from 120.5 to 10.6 MPa and is 9.2% of the strength of the feedstock. Humidity of tuff in time increases according to the law of a quadratic parabola with a complex argument, the force of indentation of the indenter from moisture and wetting time changes according to the logarithmic law, strength from humidity and time - according to the law of the quadratic parabola. Also, the article proposes an algorithm for calculating humidity and strength characteristics during wetting during the day. It is advisable to use this technology of softening tuff with water as an ore preparation operation with the integrated technology of tuff processing.