Sintering and Crushing

Nodulizing is another process of size enlargement by fusion. This employs a rotary kiln like those used for cement manufacture. The product is uniform, about 0.5 in. dia, and more dense than sinter. 

Sintering of powdered metals such as aluminum, beryllium, tungsten, and zinc as well as ceramics under pressure is widely practiced as a shaping process, but that is different from the sintering process described here. 

Model Roll dia./mm Max. roll Position of width/mm rolls/feeder Max. force/ metric tons Overload system Approx. capacity/ kg 1 Feeder type Press drive/ kW Feeder drive / kW Roll shapes Max. feed temp./ °C 

L 200/50 200 50 horiz./vert. or vert./horiz. 10 None 10-100 screw 3/4 05 smooth/corrugated/ pocketed 80 

B 100 130 50 vertical/horizontal 10 hydraulic 20 screw smooth/corrugated/ ambient 

Model Roll dia./mm width/mm rolls/feeder tons system kg Feeder type kW kW Roll shapes temp./ °C 

TABLE 12.16. RoEE Pressing Equipment Offered by Two Manufacturers 

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Fluidized and Spouted Beds 362 Sintering and Crushing 363 References 370... 

Sinter strand Crushing Hot screening Cooling and cold screening — ( blast... 

The first step involves blending the compound which will act as the host lattice with the dopant (and/or co-dopant) and the fluxes, the mixture then being fired in an unreactive container. The dopant, usually in the form of a simple salt, can be added either during or after the firing of the host. The fired product is usually sintered and then crushed, milled, and sorted to remove the coarse particles. In some syntheses the product may then undergo surface treatments, and some or all of these processes may be carried out several times. 

Calcium hydroxide [1305-62-0] M 74.1. Heat analytical grade calcium carbonate at 1000° during Ih. Allow the resulting oxide to cool and add slowly to water. Heat the suspension to boiling, cool and filter through a sintered glass funnel of medium porosity (to remove soluble alkaline impurities). Dry the solid at 110° and crush to a uniformly fine powder. 

Thermal conductivity of sintered and fused deposits found by the Australian researchers range from 0.5 x 10" kW/mK at 800 K to 2.0 X 10" kW/mK at 1500 K. This is consistent with the recent findings of Fetters et al. (3 ) for crushed deposits from a boiler fired with Indiana coal and with other literature values ( ). The increase of thermal conductivity of sintered and fused deposits is due to a decrease of void space and increased transmissivity of the material. Wall et al. emphasize that values of k obtained from ground deposits in laboratory studies are questionable since bounding of the deposit occurs in situ which leads to an increase of k. This agrees with our results for a 700 MW boiler which yielded an overall value of k - 3.2 x lO"" kW/mK for deposits which could not be removed by soot blowing (see below). 

The sinter is discharged as a large mass and falls into a claw breaker. From the breaker, the sinter is crushed and sized through rolls. A portion of the sinter is crushed to about one-half inch and stored for futme use as return sinter in the mixed feed. The finish sinter is transported to storage bins for smelting in the blast furnaces. 

Well-defined surface chemistry No sintering at high temperatures Good abrasion resistance and crushing strength Well-defined porosity, pore size distribution, and pore volume Easy separation from the reactants... 

The sinter is crushed in a mortar and particles of size 0.35-0.84 mm are separated by sieving for packing into a reaction tube. In preparing hybrid catalyst, two catalysts of Cu-Zn0-Ga203 and Y-AI2O3 are admixed at different mass ratios and then fixed into a reaction tube. 

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