With the improvement of construction sand standard and the increasing shortage of natural sand resources, mechanism sand has become the main source of aggregate for modern engineering construction. Among many sand making equipment, roll crusher stands out with its unique structural design and high efficient crushing performance, especially in the sand particle shape control, grading optimisation and environmental protection and energy saving. This article will comprehensively analyse the core value of roll crusher from three aspects: technical principle, sand making effect and practical application cases.
I. Principle of sand making technology of roll crusher
The roller crusher consists of two rollers installed parallel to each other. And the surface of the rollers can be designed as toothed, grooved or glossy according to the demand. Its core working principle is the combination of ‘laminar crushing’ and ‘selective crushing’:
1. Squeeze Crushing: After the material enters the gap between two rollers, it will be squeezed and crushed through the relative rotation of the rollers, and the crushing force can be precisely controlled by adjusting the roller distance;
2. Shear grinding: the texture of the roller surface produces shear effect on the material, reducing the phenomenon of over-crushing;
3. Self-cleaning design: non-crushed materials (such as metal impurities) can be automatically discharged through the hydraulic system to protect the safety of the equipment.
The low speed, high pressure crushing method reduces energy consumption and ensures a uniform material size usually in the range of 2-10 mm.
Second, the key advantages of sand making effect
1. Excellent sand particle size and adjustable gradation
The roller crusher can accurately control the particle size distribution of the discharged material by adjusting the roller gap and rotating speed. Experimental data show that the needle flake content of the mechanism sand it produces is less than 8%. Which is significantly better than that of the impact sand making machine (15%-20%). And the multi-stage screening system can generate Zone II medium sand (fineness modulus 2.6-3.0). Which meets the grading requirements of concrete below C60.
2. Controllable stone powder content
The matching powder selector of the equipment can stabilise the stone powder content between 7%-15%. Solving the problem of decreasing concrete strength caused by excessive stone powder in the traditional sand making process.
3.Double superiority in energy consumption and environmental protection
Compared with similar equipment, the energy consumption of the roll crusher is 30%-40% lower (for example, for limestone sand making. The electricity consumption per tonne is ≤1.8kW-h), and with the fully enclosed structure and pulse dust removal system. The dust concentration at the work site is ≤10mg/m³, which meets the national environmental protection standard of ultra-low emission.
4.Strong adaptability of raw materials
It can handle all kinds of rocks with compressive strength ≤160MPa (e.g. granite, basalt, river cobbles). And can also shape the recycled aggregates from construction waste, increasing the resource utilisation rate to more than 95%.
Roll crusher is reshaping the pattern of mechanism sand production with its excellent sand making effect, flexible regulating ability and significant environmental benefits. Driven by the policies of green mine construction and construction solid waste resources. This equipment is expected to become the core equipment for high-quality mechanism sand production, providing key technical support for the sustainable development of the industry.
