Ring-roller mill

Ring-Roller Mills without Internal Classification. 20-44... 

TABLE 20-5 Operating Data for Grinding and Drying of Bauxite in a Ring-Roller Mill... 

Ring-roller mills should be distinguished from roller mills. Paint roll mills are described under Disk Attrition Mills, and flour roll mills under Cereals and Other Vegetable Products. ... 

The Wilhams ring-roller mill Williams Patent Crusher Pulverizer Co.) is an air-swept mill with integral classifier of the rotating-blade type (the Spinner air classifier) or a double-cone type. The fluid-bed roller mill system has jets to introduce hot air into the bed of coal in the mill to diy it. 

A Raymond 5057 ring-roller mill pulverizing fluorspar produces 4500 kg (10,000 lb) of product per hour 95 percent minus 200 mesh with 104 kW (140-hp) operating power, or 26 kWh/Mg (23.4 k 4i/ ton). Fluorspar is also ground in continuous-tube mills with classification. 

Gypsum When gypsum is calcined in rotaiy Idlns, it is first crushed and screened. After calcining it is pulverized. Tube mills are usually used. These impart plasticity and workability. Occasionally such calcined gypsum is passed through ring-roller mills ahead of the tube mills. 

Sulfur The riug-roUer mill can be used for the fine grinding of sulfur. Inert gases are supplied instead of hot air (see Properties of Sohds Safety for use of inert gas). Performance of a Raymond No. 5057 ring-roller mill is given in Table 20-34. The total cost might be 3 to 4 times the power cost and include labor, inert gas, maintenance, and fixed charges. 

Other coarse crushers Hammer mill Single roll crusher Pin mill Symons disc crusher Griffin mill Ring roller mill (Lopulco) Ball mill Tube mill Hardinge mill Babcock mill... 

Closed circuit grinding employs a means whereby only material smaller than a specified size appears in the product. A less precise mode of operation employs an air stream through the equipment at such a rate that only the appropriately fine material is withdrawn and the rest remains until it is crushed to size. Ball mills sometimes are operated in this fashion, and also the ring-roller mill of Figure 12.4(a). For closer size control, all of the crushed material is withdrawn as it is formed and classified externally into product and recycle. The other examples of Figure 12.4 illustrate several such schemes. 

Colors and pigments hammer, jet, and ring-roller mills... 

TABLE 12.7. Some Other Kinds of Disintegrators (a) Ring Roller Mills to Make Down to 100 Mesh... 

Note CC is closed circuit grinding the ring-roller mill has built-in air classification. 

This type has particular application for dry grinding since the material remains in suspension and is conveyed pneumatically thruout its residence in the mill. The Whizzer classifer is a type particularly applicable to internal use with the Ring-Roller mill... 

In industrial and laboratory settings the subdivision process more commonly involves the comminution of large particles or aggregates into smaller sizes, either dry with subsequent dispersion (size reduction to the order of a few pm) or directly in a slurry (size reduction to as small as a few tenths of pm). Examples of comminution machines include agitator ball mills, colloid mills, cutting mills, disk mills, homogenizers, jet mills, mechanical impact mills, ring-roller mills, and roll crushers. 

---