Zinc particles

In steel-on-steel lubrication with a zinc dialkyl dithiophosphate additive, a complex surface paste appears to form first of zinc particles and iron dithiophosphate. The iron dithiophosphate then thermally degrades to a brown surface film of ZnS, ZnO, FeO, plus some iron and zinc... 

Whereas many of these technologies are not really new, they have never had the regulatory and economic justification for their use in metallizing. Each of these general methods has many variants. Some may be directed to waste treatment, some to recycle, and some to reclaim. An example is filtration, used to prevent release to air of zinc particles from flame spraying, microfiltration of cleaners to extend hfe, in combination with chemical precipitation to remove metal particles from wastewater, and many other uses. 

The loss of active zinc and the evolution of hydrogen, causing an intolerable rise of internal pressure, were retarded by amalgamation of zinc particles. For quite long time (up to about 1982) mercury contents of 6% (in some cases up to 8%) were regarded as normal [21]. Then a rapid decrease in the mercury content took place (Fig. 1). 

Another type of zinc-air system is designed and investigated - the so-called zinc-air fuel cell. It consists of a cell with two air electrodes and an inert anode. Slurry from zinc power dispersed into the electrolyte is circulating through the cell, by which the zinc particles are discharged on an inert electrode. 

Figure 1.7. Shapes of solidified droplets (particles) generated in powder production and spray forming processes, (a) Spherical shape gas-atomized gold alloy particles (b) near-spherical and dendritic shapes water-atomized bronze particles (c) irregular and porous (spongiform) shapes water-atomized zinc particles (d) irregular aggregates water-atomized copper particles (Cour. tesy of Atomizing Systems Ltd., UK.)...

The cell uses a replaceable anode cassette made up of a slurry of elec-trochemically generated zinc particles in a potassium hydroxide solution with a collection frame and a separator envelope with two sides of oxygen reduction cathodes that extract oxygen from the air for the zinc-oxidation reaction. The discharged zinc-air module is refueled or mechanically recharged by exchanging spent cassettes with fresh cassettes. 

These samples demonstrated exceptional durability regardless of surface preparation, due to the moisture resistant chemical and physical interlocking of the paint/adhesive interface. In addition, the zinc particles within the paint are encapsulated by the organic resin. Since few, if any, metal oxide sites are available for hydrolysis by moisture at the interface, more durable joints are the end result. 

This activated zinc would be an aggregation of very fine zinc particles dispersed in the DMF solution. The size of these particles is smaller than that obtained in the previous process, which was performed in the absence of naphthalene12. This electrochemical method is comparable to the chemical Rieke procedure in which the activated zinc is prepared by reduction of zinc halide with alkali metal naphthalenide in THF13. 

Figure 11.5. Pressure drop ratio as a function of mass flux ratio for 10 [im zinc particles in the acceleration region of Re = 53,000 (after Shimizu et al., 1978).

Numerous lead, antimony particles were detected accompanied by copper, zinc particles, iron particles, and lead-only particles. The lead, antimony copper, zinc and lead-only particles, probably originated from the bullets and the iron particles probably originated from the car bodywork. No unique FDR particles or other FDR particle types were detected. 

The precipitated nickel is composed of nickel on zinc particles with a covering of zinc oxide and other zinc compounds. 2 These zinc compounds are removed by the acid wash to expose the metallic nickel. Since the presence of the zinc prevents the oxidation of the nickel when exposed to mild oxidation... 

Alteration of the physical state and size of the insulin-zinc particles (amorphous versus crystalline). 

ZnO displays similar redox and alloying chemistry to the tin oxides on Li insertion [353]. Therefore, it may be an interesting network modifier for tin oxides. Also, ZnSnOs was proposed as a new anode material for lithium-ion batteries [354]. It was prepared as the amorphous product by pyrolysis of ZnSn(OH)6. The reversible capacity of the ZnSnOs electrode was found to be more than 0.8 Ah/g. Zhao and Cao [356] studied antimony-zinc alloy as a potential material for such batteries. Also, zinc-graphite composite was investigated [357] as a candidate for an electrode in lithium-ion batteries. Zinc particles were deposited mainly onto graphite surfaces. Also, zinc-polyaniline batteries were developed [358]. The authors examined the parameters that affect the life cycle of such batteries. They found that Zn passivation is the main factor of the life cycle of zinc-polyaniline batteries. In recent times [359], zinc-polyfaniUne-co-o-aminophenol) rechargeable battery was also studied. Other types of batteries based on zinc were of some interest [360]. 

Warren HS, Huff JE, Gerstner HB Vinyl Chloride A Review 1835-1975 An Annotated Literature Collection 1835-1975 A Literature Compilation 1976-1977. Oak Ridge, TN, Oak Ridge National Laboratory, 1978 Wilde C Aerosol metallic paints deliberate inhalation a study of inhalation and/or ingestion of copper and zinc particles. International Journal of the Addictions 10 127-134,1975... 

Therefore the amalgamation of zinc particles or the use of alternative corrosion inhibitors is necessary. But also harmful effects of dissolved metal impurities can be reduced. In commercial batteries the mercury content has been gradually reduced from 0.5 % of total cell weight in 1985 to 0.025 % in 1990 [25]. 

There are few data regarding the speciation of zinc released to the atmosphere. Zinc is removed from the air by dry and wet deposition, but zinc particles with small diameters and low densities suspended in the atmosphere travel long distances from emission sources. 

Wind-blown dust transports zinc bound to soil particulates into the atmosphere (EPA 1980d). The particulates may also contain other materials (Pacyna et al. 1989 Saltzman et al. 1985). Zincbearing particles in the atmosphere are transported to soil and water by wet deposition (rain and snow) and dry deposition (gravitational settling and deposition on water and soil surfaces). The detection of zinc in rainwaters (at concentrations higher than atmospheric particles) confirms the importance of wet precipitation in the removal of zinc particles from the atmosphere (Aten et al. 

Colin et al. 1990 Dasch and Wolff 1989 Heaton et al. 1990). Zinc particles with low dry deposition velocities (i.e., particles with small diameters and low densities) can be transported from their emission source to distant regions (Pacyna et al. 1989). 

Wilde C. 1975. Aerosol metallic paints Deliberate inhalation A study of inhalation and/or ingestion of copper and zinc particles. Int J Addict 10 127-134. 

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