Powder mixing electrostatic charge

Staniforth JN, Rees JE. 1982. Electrostatic charge interactions in ordered powder mixes. J. Pharm. Pharmac. 34 69 76. 

One possibility to improve the structure of compacts is to reduce friction (see also Section 8.2, Fig. 8.3). The addition of lubricants (see also Section 5.1.2) was first introduced in the pharmaceutical industry for the improvement of tablette quality from high speed punch-and-die presses (see below). Even today, lubricants are often a considerable part of the formulation of solid drug dosage forms. Mixed into the entire powder mass such lubricants must be included as inert excipients but always constitute additives that need to be accounted for. Because interparticle friction is normally very little affected by mass lubrication, the amount of lubricants, which, in reality, is meant mostly to reduce wall friction, must be much higher than is commensurate with its effect. Therefore, developments were directed toward the lubrication of only the tool surfaces. For this task, nozzles and solenoid valves which operate reliably in millisecond intervals were used and, later, the lubricant was also electrostatically charged to become attracted by and adhere to the tooling walls [B.42]. 

Boiling point, 295 Melting point, C 131 Flashpoint,152 Relative density (water "i1) 1.5 Relative vapor density (air >-1) 5.1 Relative density at 20" C of saturated mixture vapor/alr(air-1) 1.0 Vapor pressure, mm Hg at 20 2.3xi0 Solubility in water, g/1(M ml 0.6 Explosive limits, vol% In air i. 7-10.5 Relative molecular mass 148.1 Gross formula WHITE CRYSTALLINE FUKES/NEEDLES OR POWDER Vapor mixes readily with air. In dry state can form electrostatic charge If stirred, transported pneumatically, poured etc. Can ignite spontaneously on exposure to air (if fine powder Is stirred up). Decomposes slowly on contact with water, forming — phthaiic add Reacts with oxidants reacts violently with nitric acid. ... 

Dust explosion possible if in powder or granular form, mixed with air. If dry, it can be charged electrostatically by swirling, pneumatic transport, pouring, etc. 

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