Colloid mills

Colloid mills are used in the paint industry, and in the pharmaceutical and food-processing industries. 

Collimation Collimators (+)-CoUinusin S. collinus Tb 365 Colloidal particles Colloidal silica Colloidal silver Colloidal state Colloidal sulfur Colloid mills Colloids... 

The preemulsified carriers contain water. These products usually require homogenization through colloidal mills or similar equipment to reduce the particle size and ultimately stabilize the product. The preemulsified as well as the clear self-emulsifying products require the use of a solvent when the carrier-active material is a soHd. 

Colloid mill Homogenizer valve "Liquid whistle"... 

By shear ac tion of the surrounding medium (Fig. 20-20/ colloid mill)... 

Colloid mills which are employed for dispersion or for emulsification fall into four main groups the hammer or turbine, the smooth-surface disk, the rough-surface type, and valve or orifice devices. 

A mathematical analysis of the action in Kady and other colloid mills checks well with experimental performance [Turner and McCarthy, Am. Inst. Chem. Eng. J., 12(4), 784 (1966)], Various models of the Kady mill have been described, and capacities and costs given by Zimmerman and Lavine [Co.st Eng., 12(1), 4-8 (1967)]. Energy requirements differ so much with the materials involved that other devices are often used to obtain the same end. These include high-speed stirrers, turbine mixers, bead mills, and vibratoiy mills. In some cases, sonic devices are effec tive. 

The APV Gaulin colloid mill has a smooth rotor, shaped like a discus. 

Easily dispersible colors are not ordinarily ground fine, since they are subsequently processed in a hquid medium in pebble mills, rolls, or colloid mills. There is, however, a tendency to grind them wet with a dispersing agent, then drying and pulverizing, after which they are easily dispersed in the vehicle in which they are used. 

Kolloid-losung /, colloid(al) solution, -mUhle, /. colloid mill, -stoff, m, -substanz,/. colloid substance, colloid, -teilchen, n. colloid(al) particle, -zustand, m. coUoid(al) state,... 

Impeller types usually used with mixing and listed in decreasing order of high volume ability (hence in increasing order of high head ability or requirement) are paddle, turbine, propeller, sawtooth impeller or propeller, cut-out impeller disc (no blades), colloid mill. 

All ball, pebble, rod and cone mills, edge runner mills, tube mills, vibration mills and some ring ball mills may be used wet or dry except where stated. The perl mills, sand mills and colloid mills may be used for wet milling only. 

When an ophthalmic ointment is manufactured, all raw material components must be rendered sterile before compounding unless the ointment contains an aqueous fraction that can be sterilized by heat, filtration, or ionizing radiation. The ointment base is sterilized by heat and appropriately filtered while molten to remove extraneous foreign particulate matter. It is then placed into a sterile steam-jacketed kettle to maintain the ointment in a molten state under aseptic conditions, and the previously sterilized active ingredients) and excipients are added aseptically. While still molten, the entire ointment may be passed through a previously sterilized colloid mill for adequate dispersion of the insoluble components. 

More recently, Brauns and Seiler (12), (13) extracted native lignin from spruce wood and then homogenized the wood in a colloidal mill. A suspension of approximately one gram of colloidal wood per liter of water was obtained. After the colloidal wood was changed to a solid form, it was found that its cell structure was completely destroyed. However, extraction of this wood with ethyl alcohol at room temperature did not yield further quantities of native lignin. These investigators have also reported the isolation of a lignosulfonic acid-carbohydrate compound. 

This mixture is passed through a colloidal mill in the presence of 0.5% soda ash solution. The fatty acid prepared in this manner does not produce voluminous froth and is more selective than ordinary fatty acid mixtures. Experimental laboratory testwork conducted on the Kolwezi siliceous ore [18] with the above-mentioned mixture, with different degrees of dispersion showed substantial differences in metallurgical results (Table 19.4). Poor results were achieved when there was no dispersion of the mixture. The best results were obtained when the mixture was treated for 10 min in an ultrasonic mixer. In each case, the mixture was dissolved in a 0.5% soda ash solution. 

For many years this plant has treated an oxide siliceous ore using the hydrolysed palm oil mixture. The palm oil-fuel oil mixture is heated to about 60°C in the presence of soda ash and then passed through a colloidal mill before it is added to the copper conditioner. A typical reagent scheme used to treat the Kolwezi siliceous ore is shown in Table 19.7. The soda ash and sodium silicate are added to the grinding mills and the palm oil emulsion to the copper conditioner. 

Colloidal particles, foams used to collect and separate, 12 22 Colloidal powders, 23 55-56 Colloidal silica, 22 380, 382, 384 applications of, 22 394 modification of, 22 393-394 preparation of, 22 392-393 properties of, 22 391-392 purification of, 22 393 Colloidal silica gels, 23 60 Colloidal solids, 7 293-294 Colloidal stability, 7 286-291 10 116 22 55 Colloidal stabilizers, in polychloroprene latex compounding, 19 857 Colloid mills, 8 702 10 127 Colloids, 7 271-303 23 54. See also Polymer colloids analysis, 7 296 applications, 7 292-296 conducting, 7 524... 

Wieringa, J.A. Dieren, F. van Janssen, J.J.M. Agterof, W.G.M., 1996, Droplet breakup mechanisms during emulsification in colloid mills at high dispersed phase volume fraction, Chemical Engineering Research Design, 74, 554-562. 

Liquid and/or solids Droplet/solid size Colloid mill, tandem shear pipeline... 

Colloidal suspensions, emulsions and solid dispersions are produced by means of colloid mills or dispersion mills. Droplets or particles of sizes less than 1 (im may be formed, and solids suspensions consisting of discrete solid particles are obtainable with feed material of approximately 100-mesh or 50 p,m in size. 

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