Dusty powder

Very easy to perform and several versions are available that are suitable for free-flowing powders, dusty powders, and cohesive powders. Handling quantities can vary from 40 L to a few grams. 

These materials are generally used as replacements for lower cost antimony trioxide in latex compounds used for textile fabrics, non-wovens, adhesives, and various other applications. Unlike antimony trioxide, Nyacol materials will not settle out, will not clog spray guns, will more easily impregnate fabrics and paper and will contribute no whitening effect. Handling of dusty powders is eliminated. In many instances the aqueous colloidal antimony pentoxide is about twice as effective as trioxide. 

It is difficult to enclose the sampler to the extent required to prevent the escape of dust and fume when handling dusty powders. 

The mixtures in these experiments contained particles all the same size hence the main cause of segregation was not present and the conclusions may not apply in the more usual case where segregation occurs. Several commercial versions of this instrument are available, some of which were designed for free-flowing powders, some for dusty powders and some for cohesive powders. They handle quantities from 40 liters down to a few grams. 

The solubility of salts in water affects the freezing and drying steps. If the salt is sparingly soluble, then large quantities of water must be sublimed to dry the salt, an expensive process that may lead to excessively dusty powder. On the other hand, if the salt is highly soluble, ice crystals will not precipitate during the freezing step rather, the... 

Since a single furnace is used for three dryway operations, calcination, hydrogen reduction and hydrofluorination, the transfer of solids is minimized. The initial charging of trays and loading these into the furnace is relatively free from dust hazard since the ammonium di-uranate feed material is damp. Special precautions are needed, however, for removal of the final uranium tetrafluoride product from the trays, since it is a dry dusty powder and tends to adhere to the trays to some extent. This operation is therefore carried out in a small glove box , i.e. in a sealed and vented... 

Customers continue to want easier incorporation of additives through multiadditive packages and convenient, hygienic physical formats (more multipacks, pellets and liquids, and fewer dusty powders). This is a well-established trend, and not novel. 

Considerations should be given not only to the effectiveness of a release agent but also its cost, the health and safety aspects, the effects on other properties, and the ease of use. In this last respect, physical form is important. The stearates are dusty powders, but alkyl phosphates are also available, and have the advantage of being liquid. 

Form Supplied in yellowish-grey dusty powder. Formres with water a mud that is difficult to filter, more easily separated by centrifugation with most organic solvents, forms a well-settling, easy-to-filter suspension. ... 

Shipping of aluminum hydroxide powders is usually in paper bags of 10 to 25 kg size. Bulk shipment by road or rail wagons is also common. Aluminum hydroxides are not hygroscopic, but could be dusty and precautions against dust inhalation should be taken during handling. 

Grains. Grains are usually prereduced powders. The quantities of sodium sulfide, hydrosulfide, and mineral salts are adjusted to give a grainy product when the paste slurry is dried on a steam-heated dmm dryer. Grains offer the advantage of not being dusty. 

Lithium Hypochlorite. High purity, anhydrous lithium hypochlorite [13840-33-0] LiOCl, is a white, lightweight, dusty, hygroscopic, and corrosive powder. The monohydrate is free-flowing, nondusty, and of reasonable density. The presence of diluents such as salt, sodium, and potassium sulfates reduces dustiness, increases bulk density, reduces reactivity, and improves storage stabiUty. The commercial product is marketed in this form. 

In a few cases, powders have been pelleted or formed in briquettes to eliminate dustiness and permit diying by through circula-... 

It is important to stress that neither sodium silicate nor silico fluoride will improve the performance of a poor, low-strength, dusty concrete floor and if the surface is too porous, there is no way that all the material applied can react with the relatively small quantity of free lime in the concrete surface. All that will happen is that the pores will be filled with non-reacted powder, producing a most unpleasant alkaline dust, which can be very irritating to the skin and eyes when the floor is put into service. 

Since disperse dye powders supplied to the dyer have been treated already to render them essentially non-dusting, dustiness problems are mainly of concern during dye manufacture [92]. Nevertheless, some dyes remain inadequately treated, or after an initially adequate treatment they may deteriorate during storage, thus giving rise to hazards in handling associated with excessive dustiness. Methods of assessing dustiness have been reviewed [92]. 

It may ignite in moist air [1], The dry powder is very dusty, and suspensions in dry air have a low minimum ignition energy, 17.1 mJ. After an induction period depending on the temperature and humidity of the atmosphere, a sample confined in a Dewar flask decomposed rapidly, with an exotherm of 200°C. Heats of solution in ethanol and in water are 0.63 and 0.65 kJ/g, respectively. [2],... 

In Europe, Copper Phthalocyanine Blue is usually supplied as a powder or as a granulate. The granulated product is somewhat less dusty but also more difficult to disperse. In the USA, P.B.15 3 also continues to be offered in the form of flushed pastes to be incorporated into oil-based printing inks. These pastes offer improved pigment dispersion and frequently afford more glossy and transparent prints. 

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