Capital Equipment News September 2018

CRUSHING – PART 2

Should a high quality shape be required, an impact crusher would be necessary to get the end product into specification.

Addressing quality parameters in crushing

I n the previous article, the major talking point was that, to execute the crushing process cost-effectively, it’s always important to deploy the correct crusher for the ideal application. This not only saves you time, but it will also save you money in the long run. The article also looked at whether geology was a major factor that determines the type of crusher to be deployed in an application. The focus now turns on how quality parameters influence the crusher to be deployed for a job at hand. Quality parameters in aggregate production are normally based on strength, size and shape of the end product. How does the end result help determine what type of crusher is needed? Johann Pruewasser, engineer at Keestrack, says to determine the most economical crusher for the job at hand, project considerations always have to start at the end. “This means that all tooling deliberations have to be informed by the quality demand of the final product, and then go step by step from the end of the process to the primary crushing stage,” says Pruewasser. Dewald Janse van Rensburg, MD of B&E International, says the final product requirement is the cornerstone of equipment selection and plant design, and certain combinations of jaw crushers and secondary crushers have proved to In Part 1 of our crushing-focused series of articles, we alluded to the substance of optimum crushing in the whole aggregate production equation. In this feature, our panel of experts further delves into product quality parameters and the significance of close cooperation between supplier and customer in order to come up with the best crushing solution for the job at hand, writes Munesu Shoko .

be more effective in achieving certain out- comes. “Customer requirements will also specify the grading envelope that must be achieved, which is the ratio between the coarser and finer aggregates. For any operation, the intended throughput rate is another key consideration in the choice of crushers and their sizes, and with com- mercial operations the market will dictate the level of demand to be satisfied, or the draw-off requirement for a specific project,” says Van Rensburg. Tyron Ravenscroft, Finlay product manager at Bell Equipment, says the strength of the material determines the crushing ratios acceptable to that material and how many crushers will be required to crush the run of mine (ROM) to the desired product sizes. “The size of the ROM will determine the size of the primary crusher to accept the ROM. The ROM size will also determine the number of crushers required to produce the desired product sizes in the acceptable crushing ratios,” says Ravenscroft. “The desired product shape will determine the type of crushers required. Should a high quality shape be required, an impact crusher will be necessary to get the end product into specification,” adds Ravenscroft.

CAPITAL EQUIPMENT NEWS SEPTEMBER 2018 8