Calcium plumbate

The purity of the zinc is unimportant, within wide limits, in determining its life, which is roughly proportional to thickness under any given set of exposure conditions. In the more heavily polluted industrial areas the best results are obtained if zinc is protected by painting, and nowadays there are many suitable primers and painting schemes which can be used to give an extremely useful and long service life under atmospheric corrosion conditions. Primers in common use are calcium plumbate, metallic lead, zinc phosphate and etch primers based on polyvinyl butyral. The latter have proved particularly useful in marine environments, especially under zinc chromate primers . 

Red lead, zinc chromate, calcium plumbate and zinc dust were for many years of special importance as pigments for metal primers. When dispersed in raw or lightly-treated linseed oil, the first three possess the ability to inhibit the corrosion of mild steel and will function very well on wire-brushed rusted surfaces. In other media the tolerance towards rusted surfaces decreases with decreasing quantities of available oil, but performance on clean steel will usually be maintained and often improved. 

Zinc phosphate is now probably the most important pigment in anticorrosive paints. The selection of the correct binder for use with these pigments is very important and can dramatically affect their performance. Red lead is likely to accelerate the corrosion of non-ferrous metals, but calcium plumbate is unique in providing adhesion to newly galvanised surfaces in the absence of pretreatment, and is claimed to behave similarly on other metals in this group. 

Calcium plumbate [12013-69-3], Ca2Pb04, density 5.7 g/cm3, is a beige powder formed from lead monoxide and calcium oxide at ca. 750 °C in a stream of air [5.150]. 

The anticorrosive properties of calcium plumbate are inferior to those of red lead [5.114], Calcium hydroxide is formed as a hydrolysis product when water penetrates through a primer that contains calcium plumbate. The pH at the metal surface then increases to ca. 11-12 which inhibits corrosion. 

The most important use is in primers for zinc-coated substrates. The pH change occurring on hydrolysis of the calcium plumbate etches the zinc surface which improves adhesion of primers, especially on hot-dip galvanized steel [5.151],... 

Stable hydrosols may be obtained similarly by reduction of arsenious oxide, dissolved in aqueous sodium hydroxide containing some other protective colloid such as gelatin or egg-albumin, by means of alkaline pyrogallol.6 Salts of metallic acids, such as sodium antimonate or calcium plumbate,-with or without the addition of protalbic acid, may also be employed as protective colloids.1... 

Although a higher temperature is required for the preparation of oxygen by this method than is the ease with barium peroxide (set p. 10), the calcium plumbate is more rapidly regenerated in the presence of air when the temperature is lowered furthermore, il is not necessary to remove the carbon dioxide from the air as in Brin s process. 

Calcium ferricyanide, Ca3 [Fe(CN) 6] 2( )12H20, may be obtained 9 by oxidising aqueous calcium ferrocyanide with calcium plumbate and carbon dioxide under pressure, at the ordinary temperature. The solid salt is separated by evaporation under reduced pressure. The salt may also be obtained by oxidation of calcium ferrocyanide with chlorine 10 and by neutralising ferricyanic acid with calcium carbonate. It yields needle-shaped crystals, which are stable in dry air. 

For very specific and limited applications the following lead-based products have been used lead suboxide, lead carbonate and lead cyanamide (mirror coatings), lead silicate (electro disposition primers), dibasic lead phosphate, tribasic lead phosphate silicate, and calcium plumbate [5.51, 5.53]. 

Antimony oxide White lead Lead sulfate Cadmium red Lead silicochromate Lead chromates Zinc chromates Cadmium yellow Calcium plumbate Chromium oxide Prussian blue Ultramarine blue Lead Barytes whiting China clay Mica Talc... 

Painting for corrosion protection usually involves a thorough cleaning of the metal surface to remove any corrosion products followed by application of a primer containing a corrosion inhibitor such as zinc chromate or calcium plumbate next follows a heavily pigmented undercoat for the purpose of reducing the permeation of water to the metal surface elimination of the internal circuit— the electrolyte), finally a third decorative coat that is resistant to the atmosphere. 

Features Removes excess metals Manuf./Distrib. Fabrichem Maypro Ind. http //www.maypro. com Calcium plumbate CAS 12013-69-3 Empirical Ca204Pb Formula 2CaO Pb02 Properties Orange to bm. cryst. powd. sol. in acids insol. in cold water dec. by hot water or CO2 m.w. 351.35 dens. 5.71 Toxicology Toxic by ing. 

Barium sulfate Calcium plumbate Cobalt sulfate (ous) Lead Lead oxide, black Lead sulfate Lithium Nickel oxide (ic) batteries, storage/dry cell Zinc... 

Trifluoromethane sulfonic acid 2,4,6-Trinitroaniline explosive ingredient Calcium plumbate Potassium chlorate explosive mfg. 

Calcium silicon Ca204Pb Calcium plumbate Ca204Si Calcium silicate Ca207P2... 

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