Tin manufacture

Tin ores were mined in the German mountains in the 16 century. The ideal metallurgical reaction for tin manufacture was... 

From antiquity, the metal tin has been connected with the planet Jupiter and had the same symbol. Early in the 16 century, Georgius Agricola in Bohemia was aware of the phenomenon of foam formation. He used the Latin expression Spuma Lupi (= the wolf s foam) to describe the effect of the strange mineral on the tin manufacturing process. 

The wolfs foam disturbing the tin manufacture in the German mountains... 

Uses of hydrogen chloride—Hydrogen chloride is sometimes used in the preparation of an ester, for example ethyl benzoate, where it acts as both an acid catalyst and a dehydrating agent. Hydrochloric acid is used primarily to produce chlorides, for example ammonium chloride. It is extensively used in the manufacture of anilme dyes, and for cleaning iron before galvanising and tin-plating. 

Chlorine is also used in the manufacture of hydrochloric acid, the extraction of titanium, and the removing of tin from old tinplate ( de-tinning ). 

Containers. Aerosol containers, made to withstand a certain amount of pressure, vary in both size and materials of constmction. They are manufactured from tin-plated steel, aluminum, and glass. The most popular aerosol container is the three-piece tin-plated steel container. Glass containers, which are usually plastic coated, generally have thicker walls than conventional glass jars. They are limited to a maximum size of 120 mL and are used for pharmaceutical and cosmetic aerosols. 

In a number of cases, identifications have been extremely difficult, because the materials were synthetic and knowledge of their existence had actually been lost. For example, several rather commonly encountered synthetic pigments, such as the lead-tin yellow often found in Renaissance and Baroque paintings, were originally misidentified or left unidentifiable until extensive research, including analyses of elemental composition and chemical and physical properties, and repHcation experiments, led to proper identification of the material and its manufacturing process. 

Flame letaidancy can be impaited to plastics by incorporating elements such as bromine, chlorine, antimony, tin, molybdenum, phosphoms, aluminum, and magnesium, either duriag the manufacture or when the plastics are compounded iato some useful product. Phosphoms, bromine, and chlorine are usually iacorporated as some organic compound. The other inorganic flame retardants are discussed hereia. 

In some cases, particularly with iaactive metals, electrolytic cells are the primary method of manufacture of the fluoroborate solution. The manufacture of Sn, Pb, Cu, and Ni fluoroborates by electrolytic dissolution (87,88) is patented. A typical cell for continous production consists of a polyethylene-lined tank with tin anodes at the bottom and a mercury pool (ia a porous basket) cathode near the top (88). Pluoroboric acid is added to the cell and electrolysis is begun. As tin fluoroborate is generated, differences ia specific gravity cause the product to layer at the bottom of the cell. When the desired concentration is reached ia this layer, the heavy solution is drawn from the bottom and fresh HBP is added to the top of the cell continuously. The direct reaction of tin with HBP is slow but can be accelerated by passiag air or oxygen through the solution (89). The stannic fluoroborate is reduced by reaction with mossy tin under an iaert atmosphere. In earlier procedures, HBP reacted with hydrated stannous oxide. 

Alkyltin Intermedia.tes, For the most part, organotin stabilizers are produced commercially from the respective alkyl tin chloride intermediates. There are several processes used to manufacture these intermediates. The desired ratio of monoalkyl tin trichloride to dialkyltin dichloride is generally achieved by a redistribution reaction involving a second-step reaction with stannic chloride (tin(IV) chloride). By far, the most easily synthesized alkyltin chloride intermediates are the methyltin chlorides because methyl chloride reacts directiy with tin metal in the presence of a catalyst to form dimethyl tin dichloride cleanly in high yields (21). Coaddition of stannic chloride to the reactor leads directiy to almost any desired mixture of mono- and dimethyl tin chloride intermediates ... 

The other commercially important routes to alkyltin chloride intermediates utilize an indirect method having a tetraalkjitin intermediate. Tetraalkyltins are made by transmetaHation of stannic chloride with a metal alkyl where the metal is typicaHy magnesium or aluminum. Subsequent redistribution reactions with additional stannic chloride yield the desired mixture of monoalkyl tin trichloride and dialkyltin dichloride. Both / -butjitin and / -octjitin intermediates are manufactured by one of these schemes. 

Methyl tert-Butylluther Methyl /-butyl ether (MTBE) is an increasingly important fuel additive. Platinum—tin and other PGM catalysts are used for the dehydrogenation of isobutane to isobutene, an intermediate step in MTBE manufacture. 

Ammonia and alcohol may be used instead of sodium alkoxides to manufacture alkoxides of titanium and other metals such as tirconium, hafnium, germanium, niobium, tantalum, aluminum, and tin. 

Ammonium chloride has a number of iadustrial uses, most importantiy ia the manufacture of dry-ceU batteries, where it serves as an electrolyte. It is also used to make quarryiag explosives, as a hardener for formaldehyde-based adhesives, as a flame suppressant, and ia etching solutions ia the manufacture of ptinted circuit boards. Other appHcations iaclude use as a component of fluxes ia ziac and tin plating, and for electrolytic refining of ziac. 

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). 

In the float-glass process, adopted by all leading plate-glass manufacturers, the molten glass is allowed to float and soHdify on the surface of a pool of molten tin which provides an ideally flat surface. The endless glass ribbon has a surface so smooth that cosdy grinding and polishing are unnecessary. 

Pewter. Modem pewter may have a composition of 90—95 wt % tin, 1—8 wt % antimony, and 0.5—3 wt % copper. Lead should be avoided by contemporary craftsman because it causes the metal surface to blacken with age. Pewter metal can be compressed, bent, spun, and formed into any shape, as weh as being easily cast. A wide variety of consumer articles ate available from domestic and foreign manufacturers. Reproductions of pewter objects from colonial times, some cast from the original molds, ate popular. The annual U.S. production of pewter exceeds 1100 t. 

Stannous Oxide. Stannous oxide, SnO ((tin(II) oxide), mol wt 134.70, sp gr 6.5) is a stable, blue-black, crystalline product that decomposes at above 385°C. It is insoluble in water or methanol, but is readily soluble in acids and concentrated alkaHes. It is generally prepared from the precipitation of a stannous oxide hydrate from a solution of stannous chloride with alkaH. Treatment at controUed pH in water near the boiling point converts the hydrate to the oxide. Stannous oxide reacts readily with organic acids and mineral acids, which accounts and for its primary use as an intermediate in the manufacture of other tin compounds. Minor uses of stannous oxide are in the preparation of gold—tin and copper—tin mby glass. 

Many organic hahdes, especially alkyl bromides and iodides, react direcdy with tin metal at elevated temperatures (>150° C). Methyl chloride reacts with molten tin metal, giving good yields of dimethyl tin dichloride, which is an important intermediate in the manufacture of dimethyl tin-ha sed PVC stabilizers. The presence of catalytic metallic impurities, eg, copper and zinc, is necessary to achieve optimum yields (108) ... 

The reaction of higher alkyl chlorides with tin metal at 235°C is not practical because of the thermal decomposition which occurs before the products can be removed from the reaction zone. The reaction temperature necessary for the formation of dimethyl tin dichloride can be lowered considerably by the use of certain catalysts. Quaternary ammonium and phosphonium iodides allow the reaction to proceed in good yield at 150—160°C (109). An improvement in the process involves the use of amine—stannic chloride complexes or mixtures of stannic chloride and a quaternary ammonium or phosphonium compound (110). Use of these catalysts is claimed to yield dimethyl tin dichloride containing less than 0.1 wt % trimethyl tin chloride. Catalyzed direct reactions under pressure are used commercially to manufacture dimethyl tin dichloride. 

---