Particle-size reduction, or comminution, is often required to prepare bulk material samples for testing. Crushing is often the initial step with materials such as mineral ores or aggregates using varying combinations of force, impact, and compression to initiate fracturing in the materials.
ZENITH's stone crushers are designed to achieve larger productivity and higher crushing ratio. We have jaw crushers, impact crushers, cone crushers, sand makers and so on. They can meet various production needs through free combinations.
ZENITHs new generation of portable crushing plants contain 7 series and 72 models, which can satisfy all kinds of production needs by free combination. Besides, the mobile crushing plants are also popular among markets. Both portable and mobile crushing plants are highly flexible. They can work on various terrible terrains and help customers get returns on investments quickly.
MS series steel platform guided by global high standard design idea, adopts the standard modular design concept, with fast delivery cycle, convenient transportation and installation, which can meet the requirements of the current construction and use of crushing and screening plant for installation cycle.
Grinding is the required powdering or pulverizing process when customers have a strict demand on final size. ZENITH can provide proper grinding equipment and solutions for different applications, such as XZM Series Ultrafine Grinding Mill whose output size can reach 2500mesh (5um)...
A complete production line cannot work without auxiliaries. At ZENITH, we are able to offer different auxiliary machines with different models to our customers according to actual conditions of projects. We have vibrating feeders, belt conveyors, vibrating screens, sand washers
American Pulverizer Company Laboratory Mills are built for laboratory, pilot plant, and other small-scale applications. They will provide a uniformly crushed product from a wide variety of organic and inorganic materials. Other applications may include: chemicals, coal, pigments, foods, clay, and other friable and fibrous materials.
Practically all of the reduction is done upon the manganese steel breaker and grinding plates in the front of the grinding chamber. These parts are subject to constant wear but can be easily and quickly replaced. Rolling rings or swing hammers deflect from tramp iron and prevent serious damage to the crusher.
Laboratory Mills have many of the construction features of our high tonnage units. Each mill is built in our own shop on specifications to fit your application. Before shipment is made they are mechanically operated. Each mill is sold on a guaranteed performance basis. We are in a position to do this as we can make test grindings on your own materials at our testing laboratory.
The size reduction operation in the plant takes place as a sequence of crushing and grinding processes. In crushing, particles are reduced in size to such a level that grinding can be conducted, while grinding allows to achieve the desired liberation size.
Besides, the process of comminution can be simple or complicated depending on the nature of the ore and the suitable degree of liberation. For example, hard rocks that come from blasting can be big as 1m in size, and require multiple stages of crushing and grinding. In addition, if the valuable mineral is finely disseminated in the ore the grinding size can be down to 40 microns, which can be achieved by two grinding stages at least.
Initial size reduction is accomplished by Jaw, cone, and gyratory crushers. It can be applied in the mine site as well as at the start of the milling plant. Medium size grains require jaw, cone, and gyratory crushers as well as roll crushers to be reduced in size. The comminution of smaller coarse particles is done by Cone, roll. Hammer crushers and rotary breakers.
Grinding is conducted in mills. There are three grinding stages, coarse grinding (hundreds of microns), fine (tens of mictons) and ultrafine grinding (<10 microns). Tumbling mills, rotary breakers, and pendulum mills are mostely used.
Both crushing and grinding require energy to reduce the ore size. However, in grinding operations we consume much more eneregy than crushing, up to 100 times ( thousands of kw compared to tens in crushing).
Additionally, some chemical reagents can be used to minimize the energy consumption of grinding, because grinding energy is minimum at pH of the point of zero electrical charges of the material surface which is known as Rebinder effect.
Wears are most important in grinding compared to crushing. Because as far we go to finer sizes wears increase due to more collosion requirment for further size reduction. Besides, the grinding media generates extra wears production
The demand for high pressure grinding rolls (HPGRs) increases recently, as they respond to features requirements. Skewing designs for HPGRs are investigating for reducing wear and promoting better grinding.