Suspension, washing machines

Tris(4-methylphenyl)bismuthine (0.482 g, 1 mmol) was added to a suspension of freshly prepared iodosobenzene (0.286 g, 1.3 mmol) in dry dichloromethane (30 ml) and the resulting mixture was sonicated at 35°C under argon on a commercial ultrasonic washing machine until the substrate was completely consumed (checked by TLC). After 2-3 h, the chalky suspension turned to a bright yellow solution of tris(4-methylphenyl)bismuthine oxide, which was quickly filtered through a Celite bed and used for further pmposes [94TL8197]. 

Two grams of chromium (II) acetate hydrate is mixed (in the absence of air) with 2.49 g. of 2,2 -dipyridyI (equivalent to 1.5 moles of dipyridyl per g.-atom of Cr). Now, 40 ml. of deaerated water is added and the resulting suspension is machine-shaken for three hours. The black precipitate is filtered off from the deep-red mother liquor (through a very fine fritted-glass filter), washed with water and alcohol, and dried over air-free PgOs. Yield about 1 g. 

Hydraulic Mining. The method used to win china clay a high-pressure (2 MPa) jet of water is aimed at the exposed vertical clay face and the clay is washed down. The suspension is then pumped to settling tanks where the impurities (chiefly mica) settle out. The purified suspension of china clay is then concentrated, filtered, and dried. Hydraulic Press. A machine used for dry pressing, or semi-dry pressing the pressure (up to 100 MPa) is applied hydraulically to the top, and sometimes also to the bottom, mould-plate. Such presses are used, for example, in dry pressing basic refractories. 

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