Agitated mills

The slurry was digested in an agitation mill using 0,8 mm beads of Z1O2, partially stabilized with Y2O3, as grinding media. After 5 min,... 

A further advance was the development of enclosed agitator mills. The horizontal design was intended to eliminate the influence of gravitational forces. Numerous design features have been optimized [7.18], [7.19], [7.22]-[7.32], The most important developments are illustrated in Fig. 7.8. 

Like agitator mills, roller mills are also used to disperse and homogenize highly viscous pigment pastes (Fig. 7.12). Roller mills are often also used for finishing (postdispersion or fine dispersion, e.g., in ink production). The fact that dirt and coarse particles float to the top in the feed nip is a beneficial side effect the roller mill acts as a filter. 

Fine Ultrafine grinders Hammer mQls with internal classification Huid-energy mills Agitation mills... 

Agitation mills are vessels of capacities between 4 and 1000 L, which contain a liquid with crushing elements such as balls or sand grains in suspension. The solid to be ground is fed by the upper section and some kind of agitation is applied, while the product is taken by the lower section through a sieve. 

Agitation mill 0.075 0.005 <1 - 102 5 Silicon, titanium dioxide, ceramics... 

The product stream from the kilns is collected in storage bins. Black ash from the bins is fine-ground in a ball mill and fed to a leacher circuit, which is a system of stirred tanks, where it is dissolved in water and the muds are separated by countercurrent decantation. The solution from the decantation is passed through filter presses the muds are washed, centrifuged, and discarded. The filtered product, a saturated solution containing 12—13 wt % strontium sulfide, is sent to an agitation tank where soda ash is added to cause precipitation of strontium carbonate crystals ... 

A blending system provides the kiln with a homogeneous raw feed. In the wet process the mill slurry is blended in a series of continuously agitated tanks in which the composition, usually the CaO content, is adjusted as required. These tanks may also serve as kiln feed tanks, or the slurry after agitation is pumped to large kiln feed basins. Dry-process blending is usually accompHshed in a silo with compressed air. 

Nearly all the energy used in the concentrators is for electric motors driving ball mills, cmshers, pumps, and the agitators of flotation cells. About half the energy is used for grinding the ore to the proper size. 

Triglycerides are important constituents of resin. In softwood, the triglycerides account for 20—40% of total resin content, and in hardwood, 40—50%. The paper industry uses the term pitch for resins that create problems in paper machines. Traditionally, pitch is controlled or reduced by aging the wood, by use of chemicals to avoid deposits on the roUs, or by intensive washing of the pulp. AH these methods add to the cost of paper production. An alternative is to add a Upase to the pulp in a reaction lasting about one hour with the help of agitation. Results from Japanese paper mills show substantial... 

FIG. 11-56 Heat-transfer equipment for fusion of solids, a) Horizontal-tank type. (Coutiesy of Sttxithers Wells Corp. ) (h) Agitated kettle. (Cowtesy of Read-Standard Division, Capital Products Co.) (c) Donble-dnim mill. (Coutiesy of FaiTel-Bitmingham Co.)... 

In the wet process, the clay is masticated in a pug mill to break up lumps and then dispersed with a dispersing aid and water to make a 40 percent solids slip of low viscosity. A hi -speed agitator such as a Cowles dissolver is used for this purpose. Sands are settled out, and then the clay is classified into two size fractious in either a Hydrosettler or a continuous Sharpies or Bird centrifuge. The fine fraction, with sizes of less than 1 [Lm, is used as a pigment and for paper coating, while the coarser fraction is used as a paper filler. 

To produce a moulding composition, aniline is first treated with hydrochloric acid to produce water-soluble aniline hydrochloride. The aniline hydrochloride solution is then run into a large wooden vat and formaldehyde solution is run in at a slow but uniform rate, the whole mix being subject to continuous agitation. Reaction occurs immediately to give a deep orange-red product. The resin is still a water-soluble material and so it is fed into a 10% caustic soda solution to react with the hydrochloride, thus releasing the resin as a creamy yellow slurry. The slurry is washed with a counter-current of fresh water, dried and ball-milled. 

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