In recent years, with the comprehensive development of infrastructure construction, the demand for gravel is rising sharply. It results in the overexploitation of natural river sand, bad ecological environment and unsafety of the riverways, and comprehensive resource exhaustion of natural sand. In this case, some policies are introduced by local governments in succession, in order to restrict river sand mining and vigorously encourage the development of mechanism sand.
The so-called mechanism sand is rock particles. The soil of rock is removed then the rock is crushed by machines and screened into rock particles, the particle size of which is less than 4.75mm. It is generally regards as the substitute of river sand in the industry. And its advantages are obvious. In 2014, the market share of it may be more than 70%. By comparison with river sand, the materials of mechanism sand can be gotten more easily. They can be obtained from local sources without regional restriction. Different ore resources or waste resources can be taken full advantage of. The adequate supply of mechanism gravel can be guaranteed from the source. Besides, the quality of mechanism sand is stable. The final product particle size and the grading can be controlled by professional sand making machines, which can ensure the excellent properties of mechanism sand in quality.