Shredding . Material reduction process comprised between the input sizes of one meter to one centimeter (0.01m), differentiating between primary crushing (from 1 to 10 cm) and secondary crushing (from 10 cm to 1 cm). Crushing involves only a physical transformation of matter without altering its nature, it is of utmost importance in various processes.
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- 1 Feature
- 2 Objective
- 3 Crushing in organic and pharmacological chemistry
- 1 Crushing in organic chemistry
- 2 Crushing in pharmacology
- 4 types
- 1 Primary crushing
- 2 Secondary crushing
- 5 Machinery
- 1 Primary titrators
- 2 Secondary crushers
- 3 Tertiary crushers
- 6 Application
- 7 Source
Crushing is the name of the different materials processing methods. Crushing is also the name of the process for reducing the particle size of a substance by grinding, such as by grinding powders in a mortar with a mallet.
Crushing, moreover, refers to the production of a homogeneous material through the mixture. The crushing converts the post-consumer waste production into a bulk material (ground material, particles) that is as homogeneous as possible.
The crushing process is necessary before subsequent process steps take place – both to obtain new materials and secondary fuels. In many techniques, crushing represents the fundamental process from which subsequent treatment processes are carried out. Due to the wide variety of materials that can be crushed, the machines tend to offer a high degree of flexibility.
Reduce the size of the pieces of material to be crushed by passing them through crushers and mills.
Crushing in organic and pharmacological chemistry
Crushing in organic chemistry
In organic chemistry, grinding is a process used to purify raw chemical compounds that contain soluble impurities. A solvent is chosen in which the desired product is insoluble and unwanted by products that are highly soluble (or vice versa). The raw material is washed with the solvent and filtered, leaving the purified product in solid form, and the impurities in solution.
Crushing in pharmacology
In pharmacology, grinding can also refer to the grinding process from one compound to another to dilute one of the ingredients, add bulk processing and handling, or to cover up undesirable qualities. For example, acetylsalicylic acid is a common asset used for many pharmacological reasons ranging from pain relief to thinning blood .
It is effective at around 500 milligrams in the body. Since 500 mg is too small to handle, market, or consume, acetylsalicylic acid is crushed with a solid, non-active, bioavailable carrier before the pill is made.
- Primary crushing.
- Secondary crushing.
Primary crushing typically reduces the size of the ore chunks to a value from 8 “to 6”. The products obtained are then screened on a vibrating screen in order to separate those particles whose size is already fine enough, with the consequent increase in the capacity of the secondary crushers.
Primary crushing is typically carried out on jaw crushers or rotary crushers. Jaw crushers usually consist of two manganese steel plates or jaws, placed one in front of the other, of which one is fixed and the other is mobile and can rotate on an axis located at its top or bottom. By means of a suitable device, a reciprocating forward and backward oscillating movement is communicated to the mobile jaw.
The ore is loaded into the space between the jaws, and from them, the mobile, in its forward movement, crushes the pieces against the fixed one. As the mobile jaw recedes, the crushed ore falls through the opening at the bottom formed by the jaws.
Rotary crushers consist of a conical crusher mass that rotates inside a fixed frusto-conical casing, open at the top and bottom. The ore to be crushed is loaded into the crusher by its upper part, and the mechanism by which the crushing is performed is based on the same crushing action of the jaw crushers
In secondary crushing, the size of the particles is reduced to a value between 3 “and 2”, leaving it in conditions to be able to pass to milling or preliminary concentration operations. The crushers used in this phase are generally of the rotary or conical type. These crushers are similar to those used in primary crushing, differing only in that they operate at relatively high speeds (approximately 500 rpm) and that the outlet opening of the crushed products is much smaller.
Different types of crushing machines are used industrially and are usually classified according to the stage a in which they are used and the size of the material treated.
Large chunks of up to 8 “to 6” product are fragmented.
There are two types of machines.
- Jaw Crushers
- Rotary crushers.
They fragment the product of the primary crushing up to sizes from 3 “to 2”, among these machines we have.
- Rotary Crushers
- Conical crushers.
They fragment the product of the secondary crushing up to sizes of 1/2 “or 3/8”, among these machines we have.
- Conical Crushers
- Roll Crushers.
The crushing or crushing of materials plays a very important role in the treatment and processing of raw materials of multiple types. In many techniques, crushing represents the fundamental process from which subsequent treatment processes are carried out.
As examples of normal use of crushing, there are the coal and mineral treatment industries , grinding of cement clinker and obtaining aggregates for concrete, for different purposes: for roads, dams, ports, railways, etc.
In the treatment of rocky solid materials, two types of crushing are fundamentally distinguished: the coarse or primary and the fine or secondary crushing; The former can be divided into pre-crushing and intermediate crushing. In the construction technique, fine crushing is subdivided into two stages (secondary and tertiary) with some frequency, as in the case of cement manufacturing.
The raw materials from the quarry or mine undergo a first crushing, which constitutes the previous crushing, until reaching sizes between 50 and 150 mm, depending on the case. The intermediate crushing of the resulting product generally gives materials of smaller sizes, close to 10 mm. Although it depends on the purpose for which the aggregates are destined, in public works (excluding the manufacture of cement ) it is not normal to continue with crushing processes to reduce the material to a dusty state.