Roll briquetter

Equipment used to reduce the size of solid waste including hammer mills, shredders, roll crushers, grinders, chippers, jaw crushers, rasp mills, and hydropulpers briquettes... 

In the briquetting process, ore fines usually are mixed with a binder and are formed into compact masses between two rotating rolls. The rolls exert pressures of 1.5-4.2 t/cm2 in forming the briquettes. In the nodulizing process, which is relatively uncommon commercially, ore fines are heated in a rotary kiln to a temperature, usually 1250—1370°C, at which the ore begins to melt and bind. The ore balls in the kiln to form nodules that are discharged and cooled. 

The most common form of dry granulation is roller compaction. A roller compaction system consists of a feed system which conveys powder between two counterrotating rolls. The powder is drawn between the rolls where a specified force is applied causing the powder to compact into a briquette or a continuous ribbon. The compacted material can then be milled in-fine or collected and milled off-line in a separate processing step (i.e., screening mill). 

In contrast, increasing the gap width between the dry granulator rollers decreases the density of the compacted ribbon or briquette (also possible when other factors, such as feed rate or roll force, are changed). This reduced densification process results in a weaker binding of API to carrier excipients, and reduced overall granulation particle size distribution and increased bypass. 

The compacting of a particulate mass by subjecting it to nominally equal pressure from every direction. The area surrounding briquette pockets on the roll surface of briquetters. 

Indentation on the surface of rolls normally forming one half of a briquette shape. 

Due to leakage at the sides of the rollers (see Section 4.2.2.4.7, Sealing the roll nip ) and, in the case of roll-type briquetting machines, the flashing or webs around the briquettes, the actual throughput of and the feed to roller presses are somewhat higher (approximately 5-15% see Section 4.2.2.4.7). 

Roll pressure and torque After determining roller diameter, width, and gap or briquette size and shape as well as roller speed, using throughput capacity and product density as input, roll force and torque as well as feed pressure must be determined. The requirements on these design parameters of a roll-type press are ... 

The press must be capable of safely supporting the roll force and sustaining the torque necessary to make a good sheet or briquette. 

A near-uniform state of stress and strain within a briquette is more difficult to achieve with a roll press than with uniaxial compaction presses (either closed mold or extrusion) because of the more complicated geometry of the pressing chamber (nip plus briquette pockets). Homogeneity (but not necessarily isotropy) could be attained if either ... 

In the case of multirow presses it may be impossible to achieve an adequately uniform distribution of the feed on the rollers. Part of the maldistribution may be due to uneven gas back-flow, particularly in the center of wide rolls (see above). The influence of uneven distribution becomes more critical as the briquette volume decreases. With very small pockets it becomes almost impossible to produce briquettes of uniform quality in multirow presses. 

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