White-lead

The manual substances mainly used as white pigments arc Lead carbonate [white lead), lead sulphate, zinc oxide [zinc white), zinc sulphide mixed with barium sulphate, these being obtained artificially artificial [fixed white) or natural barium sulphate, natural or artificial calcium carbonate [chalk), natural or artificial calcium sulphate [gypsum). 

More rarely use. as white, pigments is made of other substances, such as bismuth suhnitrate, antimony oxide and oxychloride. Many other white sulwtances insoluble iu water could 1m used similarly, such as kaolin, talc, silica, bone ash, etc.., but these an- not generally used as they are less suitable or less convenient than those indicated above, or they are only used in certain cases to mix with other colours. 

The complete analysis of each of the more important white pigments is described below. The following scheme (Table XL) of reactions serves fertile ready differentiation of the various whites (when not mixed), without following the geneial procedure of qualitative analysis. 

This consists of a basic carbonate, corrc-sponding in composition approximately with the formula, 2pbC0 Pb(OH), It may contain various impurities resulting from the manufacture, especially basic lead acetate and it may he adulterated with barium sulphate, lead sulphate, zinc white, bone-ash, witlicrite, gyi sum, chalk or clay (kaolin). Mixtures of white lead with barium sulphate an given special names, e.g. Venetian white (equal weights of white lead and barium sulphate), Hamburg white (l part of white lead to i parts of barium sulphate), Dutch white (i part of white lead to 3 parts of barium sulphate). Wliite lead mixed with gum and moulded into cakes is termed Krem s white. 

Analysis of white lead includes, besides technical tests [see General Methods), qualitative examination for the detection of impurities and adulterants [see paragraph i) and certain quantitative determinations (see succeeding paragraphs), 

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If the normal carbonate is used, the basic carbonate or white lead, Pb(OH),. 2PbCO,. is precipitated. The basic carbonate was used extensively as a base in paints but is now less common, having been largely replaced by either titanium dioxide or zinc oxide. Paints made with white lead are not only poisonous but blacken in urban atmospheres due to the formation of lead sulphide and it is hardly surprising that their use is declining. 

Ozone is very much more reactive than oxygen and is a powerful oxidising agent especially in acid solution (the redox potential varies with conditions but can be as high as + 2.0 V). Some examples are 1. the conversion of black lead(ll) sulphide to white lead(II) sulphate (an example of oxidation by addition of oxygen) ... 

Lead(II) sulphide is oxidised to lead(II) sulphate this reaction has been used in the restoration of old pictures where the white lead pigment has become blackened by conversion to lead sulphide due to hydrogen sulphide in urban air ... 

Zinc oxide or zinc white is used in paints, but more preferable, because of its better covering power, is lithopone (a mixture of zinc sulphide and barium sulphate). Both paints have the advantage over white lead that they do not blacken in air (due to hydrogen sulphide). Zinc dust and also zinc chromate are constituents of... 

The metal is very effective as a sound absorber, is used as a radiation shield around X-ray equipment and nuclear reactors, and is used to absorb vibration. White lead, the basic carbonate, sublimed white lead, chrome yellow, and other lead compounds are used extensively in paints, although in recent years the use of lead in paints has been drastically curtailed to eliminate or reduce health hazards. 

Theophrastos (272—287 Bc) studied the utilisation of acetic acid to make white lead and verdigris [52503-64-7]. Acetic acid was also weU-known to alchemists of the Renaissance. Andreas Libavius (ad 1540—1600) distinguished the properties of vinegar from those of icelike (glacial) acetic acid obtained by dry distillation of copper acetate or similar heavy metal acetates. Numerous attempts to prepare glacial acetic acid by distillation of vinegar proved to be in vain, however. 

PbO PbO H2O, for example, may be formed by boiling suspensions of lead oxide and lead sulfate in water. In addition, complex mixed salts, such as white lead, 2PbC02 Pb(OH)2, are readily formed. 

Basic Lead Carbonate. Basic lead carbonate [1319-46-6] (white lead), 2PbC03 Pb(OH)2, mol wt 775.67, d = 6.14g/cm, forms white... 

Although white lead was the oldest white hiding pigment ia paints, it has been totally replaced by titanium dioxide, which has better covering power and is nontoxic (see Pigments). Nevertheless, basic lead carbonate has many other uses, including as a catalyst for the preparation of polyesters from... 

Various other soft materials without the layer—lattice stmcture are used as soHd lubricants (58), eg, basic white lead or lead carbonate [598-63-0] used in thread compounds, lime [1305-78-8] as a carrier in wire drawing, talc [14807-96-6] and bentonite [1302-78-9] as fillers for grease for cable pulling, and zinc oxide [1314-13-2] in high load capacity greases. Graphite fluoride is effective as a thin-film lubricant up to 400°C and is especially useful with a suitable binder such as polyimide varnish (59). Boric acid has been shown to have promise as a self-replenishing soHd composite (60). 

The Sperry process for making white lead ia an electrolytic cell recovers bismuth as a by-product ia the anode slimes. 

Carbon dioxide is used as a chemical reagent in the manufacture of sodium saHcylate, basic lead carbonate or white lead, and sodium, potassium, and ammonium carbonates and bicarbonates. 

Cellulose acetate Silica gel Scoured wool Sawdust Rayon waste Fluorspar Tapioca Breakfast food Asbestos fiber Cotton linters Rayon staple Starch Aluminum hydrate Kaolin Cryolite Lead arsenate Cornstarch Cellulose acetate Dye intermediates Calcium carbonate White lead Lithopone Titanium dioxide Magnesium carbonate Aluminum stearate Zinc stearate Lithopone Zinc yellow Calcium carbonate Magnesium carbonate Soap flakes Soda ash Cornstarch Synthetic rubber... 

The concept of the corrosion process, derived from the Latin corrodere (to eat away, to destroy), first appeared in the Philosophical Transactions in 1667 [2]. It was discussed in a German translation from the French on the manufacture of white lead in 1785 and was mentioned in 1836 in the translation of an English paper by Davy on the cathodic protection of iron in seawater [3]. However, almost until the present day, the term was used indiscriminately for corrosion reaction, corrosion effects, and corrosion damage. Only in DIN 50900, Part I, were these terms distinguished and defined [4] (see Section 2.1). 

A frequently cited example of protection from atmospheric corrosion is the Eiffel Tower. The narrow and, for that age, thin sections required a good priming of red lead for protection against corrosion. The top coat was linseed oil with white lead, and later coatings of ochre, iron oxide, and micaceous iron oxide were added. Since its constmction the coating has been renewed several times [29]. Modern atmospheric corrosion protection uses quick-drying nitrocellulose, synthetic resins, and reaction resins (two-component mixes). The chemist Leo Baekeland discovered the synthetic material named after him, Bakelite, in 1907. Three years later the first synthetic resin (phenol formaldehyde) proved itself in a protective paint. A new materials era had dawned. 

For this reason tribasic lead sulphate, a good heat stabiliser which gives polymer compounds with better electrical insulation properties than lead carbonate, has increased in popularity in recent years at the expense of white lead. Its weight cost is somewhat higher than that of lead carbonate but less than most other stabilisers. This material is used widely in rigid compounds, in electrical insulation compounds and in general purpose formulations. 

Gaseous CO2 is extensively used to carbonate soft drinks and this use alone accounts for 20% of production. Other quasi-chemical applications are its use as a gas purge, as an inert protective gas for welding, and for the neutralization of caustic and alkaline waste waters. Small amounts are also used in the manufacture of sodium salicylate, basic lead carbonate ( white lead ), and various carbonates such as M2CO3 and M HC03 (M = Na, K, NH4, etc.). One of the most important uses of CO2 is to manufacture urea via ammonium carbamate ... 

BerL Ber., abbrev. (Berliner Berichte) Berickte der deutscken chemiachen Gesellscka/t. Berliner-blau, n. Berlin blue, Prussian blue, -blaus ure, /. hydrocyanic acid, -braun, n. Prussian brown, -griin, n. Prussian green, -rot, n. Berlin red (a red lake color), -saure,/. prussic acid, -weiss, n. a kind of white lead. Bernstein, m. amber. — schwarzer —, jet. Bernstein-, amber succinic, succinyl, succino-. -alaun, m. aluminous amber, -aldehyd, n. succinaldehyde. bemateinartig, a. amber-like. 

Weiss-blech, n. tin plate, -biechdose, /. tin can, tin box, tin. -blechwaren, f.pl. tinware, -blei, n. tin. -bleiche, /. bleaching, full bleach, -bleierz, n. white lead ore, cerussite. -biiitigkeit, /. leukemia, leucocythemia, -boden, m. Tech.) white ground, -brenneo, n, calcining at white heat, -brot, n. white bread, wheat bread. 

Ester gum varnish White lead/ zinc oxide I-I22 4... 

Inorganics are denser and usually of a larger particle size. Common inorganic pigments include iron oxides in buff colors, titanium dioxide in white, lead and zinc... 

The history of lead is almost as ancient as that of tin. In Roman times, lead was formed into pipes that were used for water supplies (hence our word plumbing, derived from the same Latin word, plumbum, that gives us the s Tnbol Pb). Lead is a component of pewter and also was used as a glaze on drinking vessels. White lead, ... 

Registered trade name(s) No data Cl 77630 Fast White Lead Bottoms Mulhouse White No data No data... 

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