Crushing & Grinding in Mining Processing

The purpose of crushing and grinding is to reduce the size of the prospective ore particles into that where there’s sufficient REE mineral liberation, and the size/size distribution is acceptable for the chosen downstream mineral recovery procedure. This permits for the subsequent REE mineral recovery processes to function in an economically efficient manner. Not only is the typical particle size an integral parameter, but the distribution of sizes will be important also, using the more narrow the magnitude distribution, the better. Each possible mineral recovery procedure has a specific size range of functionality, and the final product of this crushing/grinding circuit needs to match the chosen procedure size requirements.

Proper grinding is vital to be able to get good metallurgical test results, as the entirety of downstream processing is determined by optimal recovery and grinding at this stage. WPE Process Equipment offer a wide range of high frequency screens equipment  in Australia. Due to this, at times the recovery and levels of the initial phase of processing concentrates would be regarded as being lower than anticipated and also elevated REE values are also found in the tailings. Occasionally, the REE mineral grains have been weathered, hydrothermally altered, or otherwise quite nice, and traditional ways of grinding and processing are substandard for producing the suitable size/size distribution to produce a first phase mineral concentration. Alternative processing routes have to be explored.

The very first stage of the crushing/grinding procedure in a production facility starts with the blasting of this ore body, where the blasted material is composed of a very broad assortment of sizes. Very fine material from the zones encompassing the blast holes, to big boulders exist, which demand extra breakage. Occasionally soft ores could be directly recovered using excavating equipment.

The material to be crushed from exploration projects comes from drill cores, trenching, chips or surface samples.

Crushing is performed in stages utilising a mix of jaw, cone and impact crushers and is done dry. The substance will be moved by mechanical means of conveyor belts. The upper size limit for crushing is approximately 1 meter, along with the final crusher product is about 1 cm.

Grinding is completed in production scale nearly exclusively with ball mills, though ball mill/rod mill mixtures have been used in the past. For lab scale work, small ball and rod mills can be employed. The grinding media for a ball socket is typically steel balls tucked out of about 1 to 10 cm in diameter, and also for pole mills about 1 to 10 cm in diameter, with the span being slightly shorter than the length of the rod mill. The grinding circuit merchandise can be made very fine, if needed, with the majority of material finer than 20 microns (um).

The product of the grinding circuit is normally split into fine and coarse fractions, together with the fine portion being sent into the downstream processing circuits and the coarse material being pumped to the grinding circuit to get extra size reduction. It’s a good idea to eliminate the fines as soon as possible from the grinding process since regrinding of this fine portion often results in the finer material which can be difficult to recover.

The grinding circuit merchandise is characterised by use in the mineral processing circuit. Terms like p80 = 106 um are utilised, meaning that 80 percent of this stuff can pass a sieve containing openings of 106 um. The personnel responsible for the milling procedure needs to work closely together with the job mineralogist to make sure that the right amount of REE mineral liberation was obtained in the grinding circuit merchandise. Just after the mineralogist has supplied their acceptance of the milling circuit merchandise, need mineral processing start. It is occasionally helpful to measure mineral processing recovery as a function of milling circuit product size. This helps the grinding engineers to produce the necessary alterations to the actual elements of the milling circuit.