Tungstene carbide mill

After a coarse grinding (to a particle size of 2-10 mm) in a stainless steel mill, the material was packed in polythene lined containers and shipped to the Joint Research Centre of Ispra (Italy) for further processing. The material was then ground in a tungsten carbide mill. A fraction of the particles of 90-200 pm was sieved out this fraction was chosen in order to eliminate possible fine clay-like particles. 

The Lawrie Tea Processor (LTP) is used in Africa to macerate lightly withered leaf. A hammer mill, in which final particle size can be controlled by degree of wither and adjustment of the tungsten-carbide-tipped beaters, is essential. 

In the present study, 12 g from each sherd was collected. Glazes and other surfaces were mechanically removed to minimize contamination from glaze and other external compounds. Following this process, specimens were powdered and homogenized in a Spex Mixer (Mod. 8000) tungsten carbide cell mill for 12 minutes. Powdered specimens were transferred to clean polyethylene vials for transportation to the laboratory. 

Microcline, albite and labradorite were obtained from Ward s Canada Limited. Cleaved crystal fragments and 60 mesh-sized samples were ultrasonically cleaned prior to use. Powdered samples (particle size < 25 ym) were prepared by grinding in a tungsten carbide ball mill, wet-sieving and washing in water. 

Fig. 1.6 Tungsten carbide and agate vials for SPEX mill...

There are many types of mechanical grinding equipment available ball mills, ball and mortar sets, planetary mortars, impact mills, etc. These are available in a variety of materials steels, porcelain, agate, mullite, silicon carbide, tungsten carbide and others. Prices range from 200 to about 2,000. Unfortunately, the cost increases rather markedly as one goes to the harder materials, especially the carbides. 

Ball milling Low ash, rubber-lined mills 12 h cycle tungsten carbide media surface, 4-10 m /g... 

Derivation Ball milling of powdered tungsten carbide with metallic cobalt, followed by sintering. 

Figure 35-1 A commercial mixer/mill for pulverizing and blending samples. Stainless steel, ceramic, and tungsten carbide vials and mixing balls are available. Also shown are multiple sample adaptors. (Courtesy of Spex Industries, Metuchen, NJ.)...

Commonly used types of grinding media are carbon steel, stainless steel, chrome steel, tungsten carbide, ceramic, or zirconia. Ball mills produce up to 50 ton/hr of powder substantially passing a 200-mesh screen. Temperature control can be achieved by the use of jacketed ball mills through which a heat transfer fluid is circulated. 

The CRM 062 consisted of freshly picked olive twigs from Pescara (Italy). After washing, the twigs were air-dried on a plastic lattice positioned ca. 40 cm above a layer of polythene. The leaves were removed by threshing with wooden rods and collected from the polythene ground sheet. Grinding took place in a tungsten carbide hammer mill. 

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