Why does an impact crusher create a more consistent material gradation than a jaw crusher?
The nature of a horizontal shaft impact crusher produces finished product with a reduction ratio of about 20:1 while jaw crusher will utilize much lower reduction ratios. The design of a compression (jaw) style crusher is principally used as a primary crusher due to its much lower reduction ratios. An impact crusher will generate more fines than a jaw crusher upon its initial pass while the secondary crushing required to produce a gradable aggregate initially crushed in a primary jaw crusher will generate a higher percentage of fines. In addition to the gradation of the material, particle shape is also very crucial to meeting gradable material specifications. The shattering of the material in a horizontal shaft impact crusher creates a more consistent cubical material shape. While a compression crusher such as a primary jaw or even a secondary cone crusher will produce a lot higher percentage of flat or elongated particles. Nearly all material specifications require the rigid spec base
