The characteristics of raw materials required for the cement production differ at a wide range. The limestone deposits used today as base material, show very different properties regarding hardness, abrasiveness and stickiness. To optimize the crushing process as well as the investment and operating costs, different types of crushers are available. To make a proper selection, several important points should be considered in advance.
Jaw crushers can be used together with mine-selecting equipments and gravel processing equipments as well as used independently. The Jaw crusher is used for Primary crushers and Secondary crushers for crushing all kinds of minerals and rocks with compressive strength less than 320 MPa. There are two types of Jaw crusher: Coarse jaw crusher and Fine jaw crusher
The very first step should always be an analysis of the quarry, and especially the characteristics of the raw material. Of prime importance is the hardness of the material to be crushed. To describe this property the compressive strength, the Los Angeles Index or the Mohs Hardness should be determined and a point load test should be carried out.
The abrasiveness of the material has to be described by its Silica and free quartz content, as well as the abrasion index. Just as important is an expression of the stickiness. For this reason the moisture, the clay content and, in very difficult applications, the handling coefficient (shear test) has to be ascertained. Based on this data an overview of the selection criteria allows a pre-choice of the required crusher.
Primary crushing of limestone for the cement production requires high crushing ratios to reduce the material in a single step, down to the required grain size (approx. 0 – 25/80mm) for the raw mills. It should always be the aim to have as few crushing steps as possible, in order to minimize the investment and maintenance costs and time.
According to the above overview, one step crushing can be achieved by operating Jaw Crushers or Impact Crushers. These crusher types are fast running machines providing high kinetic energy, resulting in strong impact forces and high crushing ratios. The allowable maximum compressive strength of 320 Mpa is normally sufficient for most of the limestone applications. With its high quality products such as Ore spiral classifier, Vibrating grizzly feeder, Cone crusher, Ball mill, Henan Hongxing mining machinery Co.Ltd has ascended in the front rank of the world in the exporting of mining equipments.

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