Tinned iron

Cementation. A metal can be removed from solution by displacing it with a mote active metal. This simple, inexpensive method has been commonly used to recover copper from dilute (1—3 kg/m ) solution using shredded iron and de-tinned iron cans as reducing agent. 

At room temperature, sulfur unites readily with copper, silver, and mercury and vigorously with sodium, potassium, calcium, strontium, and barium to form sulfides. Iron, chromium, tungsten, nickel, and cobalt react much less readily. In a finely divided state, zinc, tin, iron, and aluminum react with sulfur on heating (19). 

Tin [7440-31 -5] is one of the world s most ancient metals. When and where it was discovered is uncertain, but evidence points to tin being used in 3200—3500 BC. Ancient bron2e weapons and tools found in Ur contained 10—15 wt % tin. In 79 ad, Pliny described an alloy of tin and lead now commonly called solder (see Solders and brazing alloys). The Romans used tinned copper vessels, but tinned iron vessels did not appear until the fourteenth century in Bohemia. Tinned sheet for metal containers and tole (painted) ware made its appearance in England and Saxony about the middle of the seventeenth century. Although tinplate was not manufactured in the United States until the early nineteenth century, production increased rapidly and soon outstripped that in all other countries (1). 

A reversal of potential of the tin—iron couple occurs when tin-coated steel (tin-plate) is in contact with acid solutions in the absence of air. The tin coating acts as an anode it is the tin that is slowly attacked and not the steel. This unique property is the keystone of the canning industry because dissolved iron affects the flavor and appearance of the product. Thus, the presence of tin protects the appearance and flavor of the product. 

Total carbon in beryUium is determined by combustion of the sample, along with an accelerator mixture of tin, iron, and copper, in a stream of oxygen (15,16). The evolved carbon dioxide is usuaUy measured by infrared absorption spectrometry. BeryUium carbide can be determined without interference from graphitic carbon by dissolution of the sample in a strong base. BeryUium carbide is converted to methane, which can be determined directly by gas chromatography. Alternatively, the evolved methane can be oxidized to carbon dioxide, which is determined gravimetricaUy (16). 

Iron plate, pickled, then rusted red 68 0.612 Tin—bright tinned iron sheet 76 0.043 and 0.064... 

Polished surface, alone 0.045 Pasted on tinned iron plate 66 0.924 ... 

Black shiny shellac on tinned iron sheet 70 0.821 Hard, glossy plate 74 0.945 ... 

Steel coated with tin (tinplate) is used to make food containers. Tin is more noble than steel therefore, well-aerated solutions will galvanically accelerate attack of the steel at exposed areas. The comparative absence of air within food containers aids in preserving the tin as well as the food. Also the reversible potential which the tin-iron couple undergoes in organic acids serves to protect exposed steel in food containers. 

To ensure maximum continuity of the tin-iron compound layer between tin and steel. This layer is itself corrosion resistant and appears to act as a nearly inert screen limiting the area of steel exposed as tin is removed by corrosion. Its effectiveness is measured by the Alloy-Tin Couple (A.T.C.) test, in which the current flowing is measured between a sample of tinplate from which the unalloyed tin layer has been removed, and a relatively large tin electrode immersed in an anaerobic fruit juice. ... 

A limited degree of control over the corrosivity of the product packed is possible. Minor pH adjustments may be helpful, especially in ensuring an anodic relation of tin to steel corrosion promoters, like nitrate, sulphur and copper may be excluded from necessary additives, such as water and sugar, and from sprays applied to crops approaching harvest. The effect of sulphur compounds which may remain from spray residues is complex but often includes reversal of the tin-iron polarity. 

Determination of copper as copper(I) thiocyanate Discussion. This is an excellent method, since most thiocyanates of other metals are soluble. Separation may thus be effected from bismuth, cadmium, arsenic, antimony, tin, iron, nickel, cobalt, manganese, and zinc. The addition of 2-3 g of tartaric acid is desirable for the prevention of hydrolysis when bismuth, antimony, or tin is present. Excessive amounts of ammonium salts or of the thiocyanate precipitant should be absent, as should also oxidising agents the solution should only be slightly acidic, since the solubility of the precipitate increases with decreasing pH. Lead, mercury, the precious metals, selenium, and tellurium interfere and contaminate the precipitate. 

Electrolytic Tinplate. Much of the tin mill product is made into electrolytic tinplate (ETP). A schematic of an ETP cross section is given in Figure 1. The steel strip is cleaned electrolytically in an alkaline bath to remove rolling lubricants and dirt, pickled in dilute mineral acid, usually with electric current applied to remove oxides, and plated with tin. It is then passed through a melting tower to melt and reflow the tin coating to form the shiny tin surface and the tin-iron alloy layer, chemically treated to stabilize the surface to prevent growth of tin oxide, and lubricated with a thin layer of synthetic oil. 

In plain tinplate cans for acid foods, tin provides cathodic protection to steel (3,4). The slow dissolution of tin prevents steel corrosion. Many investigators (5-1I) have defined this mechanism in detail and have shown that the tin dissolution rate is a function of the cathodic activity of the base steel, the steel area exposed through the tin and the tin-iron alloy layers, and the stannous ion concentration. Kamm et al. showed that control of the growth of the tin—iron alloy layer provides a nearly continuous tin-iron alloy layer and improves the corrosion resistance of heavily coated (over 45 X 10"6 in. tin) ETP for mildly acid food products in which tin provides cathodic protection to steel (12). The controlled tin-iron alloy layer reduces the area of steel exposed to the product. ETP with the controlled alloy is designated type K, and since 1964, 75 type K ETP has been used to provide the same protection as 100 ETP provided previously (13). 

Blank Tin Iron Zinc Copper Metal Species... 

From blister copper, residual sulfur and impurities such as aluminum, silicon, manganese, zinc, tin, iron, nickel, arsenic, antimony and lead are first eliminated by oxidation and slagging. At the end of this stage excess oxygen remains in the partly purified copper, and this is removed by a deoxidation process. 

Anthocyanins can form complexes with metal ions such as tin, iron and aluminium. The formation of a complex, as expected, alters the colour, usually from red to blue. Complex formation can be minimised by adding a chelating agent such as citrate ions. Another problem with anthocyanins is the formation of complexes with proteins. This can lead to precipitation in extreme cases. This problem is normally minimised by careful selection of the anthocyanin. 

In one sense, the creation of alchemy represented a step backward. The Egyptians had known seven metallic elements gold, silver, copper, tin, iron, lead, and mercury, which they associated with the seven planets (Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn, respectively). The Greeks, however, failed to recognize them as distinct elements. According to the Aristotelian theory, the metals were mixtures of the traditional four elements. This idea seemed to... 

Chemical precipitation is applicable to most heavy metals likely to be found in contaminated gronndwater. Examples of metals that have been removed to a concentration of less than 1 ppm inclnde cadminm, chrominm, nickel, zinc, manganese, copper, tin, iron, arsenic, lead, and mercnry. Chemical precipitation is widely nsed to meet National Pollution Discharge Elimination System (NPDES) reqnirements for the treatment of heavy-metal-containing wastewaters. In many cases, metals precipitation may also be nsed as a pretreatment step prior to discharge of the wastewater to a pnblicly owned treatment works (POTW). 

Bickford s Collier Safety Lighter, invented in 1889, consists of a tube (tinned-iron or steel) closed at one end and containing a mixture of KC103 and sugar, pressed into a pellet not... 

When he discusses the chemical aspects of metals, Boerhaave resorts to alchemical descriptions, which still utilize the mercury-sulphur conception that had largely been abandoned even if not refuted nor completely superceded. There are only six simple metals, he says, gold, silver, copper, tin, iron, and lead ... 

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