Dusts and granules

It is important to know the concentration of insecticide on the label. For dry formulations such as WPs, dusts, and granules, the insecticide concentration is expressed in percentage of active ingredient (AI) in the formulation. For example, Diazinon 50W means that 50% of diazinon is in the WP formulation. On the other hand, for liquid formulations such as solutions and emulsifiable concentrates, the concentration of insecticide is expressed in pounds of Al/gal of the formulation. For example, Diazinon 4E means that 4 lb of diazinon is in each gallon of the formulation. 

Splashes, errant sprays, mists, clouds, etc., of pesticide vapors, aerosols, hquids, dusts, and granules are potential sources of facial contact with the pesticides. Although facial contacts would be expected to occur less frequently than, for example, contact with the hands, the health consequences of the contacts are potentially more serious, especially for contacts with the eyes. 

How to Use You can purchase BT in many forms, including liquids, powders, dusts, and granules. Follow label directions for either dusting on plants or preparing and applying a batch of spray solution. If sprays roll off leaves rather than adhering to them, add a few drops of liquid dish soap to the spray solution to enhance sticking. 

Since 1962, agrochemicals and chemical fertilisers have been distributed in Nepal by the Agriculture Inputs Corporation (AIC), a public enterprise owned by the government. Private sector traders also play a major role in pesticide distribution, reselling agrochemicals purchased from AIC. In 1994, AIC distributed about 335 metric tonnes of dust and granulated pesticides and about 2460 litres of liquid pesticides. ... 

In the chemical industry vacuum conveying is mainly used for the transport of raw materials and additives which are required for the various processes and treatments. Transferred are bulk materials like powders, dusts and granules and sometimes even viscous products or liquids. 

Typically, dry potassium nitrate is pulverized in a ball mill. Sulfur is milled into cellular charcoal to form a uniform mix in a separate ball mill. The nitrate and the sulfur—charcoal mix are screened and then loosely mixed by hand or in a tumbling machine. Magnetic separators may be used to ensure the absence of ferrous metals. The preliminary mix is transferred to an edge-mimer wheel mill with large, heavy cast iron wheels. A clearance between the pan and the wheels is required for safety purposes. The size of this gap also contributes to the density of the black powder granules obtained. Water is added to minimize dusting and improve incorporation of the nitrate into the charcoal. The milling operation requires ca 3 to 6 h. 

Safety is assessed by subjecting the antioxidant to a series of animal toxicity tests, eg, oral, inhalation, eye, and skin tests. Mutagenicity tests are also carried out to determine possible or potential carcinogenicity. Stabilizers are being granulated and Hquid products are receiving greater acceptance to minimize the inhalation of dust and to improve flow characteristics. 

The cyanide, which crystallizes in the anhydrous state from aqueous solution, is recovered by evaporation under reduced pressure, filtration, and drying. Because the crystal size is significantly larger than sodium cyanide it can be sold in powder form without excessive dusting. However, it tends to cake in the shipping container and is often compacted and granulated to larger sizes. 

Cleanable Granular-Bed Filters The principal objective in the development of cleanable granular-bed filters is to produce a device that can operate at temperatures above the range that can be tolerated with fabric filters. In some of the devices, the granules are circulated continuously through the unit, then are cleaned of the collected dust and returned to the filter bed. In others, the granular bed remains in place but is periodically taken out of service and cleaned by some means, such as backflushing with air. 

The synthesis of deoxybenzoin from phenacetyl chloride and benzene by the Friedel-Crafts reaction has been described. For symmetrically substituted deoxybenzoins, direct reduction of the readily accessible benzoin is a more convenient method. Reduction of benzoin by zinc dust and acetic acid, and by hydrochloric acid and granulated tin or amalgamated powdered tin has been reported. The present method is based on a publication of the authors. ... 

After a pesticide is manufactured in its relatively pure form (the technical grade material) the next step is formulation - processing a pesticide compound into liquids, granules, dusts, and powders to improve its properties of storage, handling, application, effectiveness, or safety [9]. The technical grade material may be formulated by its manufacturer or sold to a formulator/ packager. 

Dry products can include dusts, powders, and granules. Dusts and powders are manufactured by mixing technical grade material with the appropriate inert carrier and grinding the mixture to obtain the correct particle size. Several rotary or ribbon blender-type mixers mix the product. Figure 6 shows a typical dry formulation unit for pesticides [8]. 

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