Alloy lead-antimony

Automobile battery grids employ about 1—3 wt % antimony—lead alloys. Hybrid batteries use low (1.6—2.5 wt %) alloys for the positive grids and nonantimony alloys for the negative grids to give reduced or no water loss. The posts and straps of virtually all lead—acid batteries are made of alloys containing about 3 wt % antimony. 

Selenium acts as a grain refiner in lead antimony alloys (114,115). The addition of 0.02% Se to a 2.5% antimonial lead alloy yields a sound casting having a fine-grain stmcture. Battery grids produced from this alloy permit the manufacture of low maintenance and maintenance-free lead—acid batteries with an insignificant loss of electrolyte and good performance stability. 

Demand for high performance SLI batteries has led to the development of smaller, lighter batteries that require less maintenance. The level of antimony is being decreased from the conventional 3—5% to 1.75—2.75% to minimise the detrimental effects. Lead alloys that contain no antimony have also been introduced. Hybrid batteries use a low antimony—lead alloy in the positive plate and a calcium—lead alloy in the negative plate. 

Type metal, another tin—antimony—lead alloy, is used primarily in reHef or letterpress printing. Antimony is added to increase hardness, minimize shrinkage, permit sharp definition, and reduce the melting point of the alloy. There has been a substantial decrease in the use of type metals as a result of the emergence of less expensive typesetting techniques. 

Prengaman, R. E., Structure Control of Non-Antimonial Lead Alloys via Alloy Additions, Heat Treatment and Cold Working, Pb80, Ed. Proc. 7lh Ini. Lead Conf., Madrid, Lead Development Association, London (1983)... 

Antimony (Sb), 3 41-56, 56. See also Group Ill-Sb system InAsSb alloy InSb photodiode detectors/arrays Lead-antimony alloys Low antimony lead alloys Stib- entries in babbitts, 24 797 catalyst poison, 5 257t chemical reactions, 3 42—44 in coal, 6 718 economic aspects, 3 47-48 effect of micro additions on silicon particles in Al-Si alloys, 2 311-312 effect on copper resistivity, 7 676t environmental concerns, 3 50 gallium compounds with, 12 360 health and safety factors, 3 51 in pewter, 24 798... 

Low-antimony lead alloys, 14 770 Low-birefringence polycarbonates, 19 822 Low-blush copolymers, 26 538 Low boiling node, in separating nonideal liquid mixtures, 22 303 Low-calorie beer, 3 577 Low calorie sweeteners, 12 38 Low calorific value (LCV) gas, 26 575—576... 

Replacement of the antimony-lead alloy in the conventional lead-acid automotive battery with a 0.1% Ca—Pb grid alloy improves the conductivity and current capability of the cell, and significantly reduces gassing, permitting the cell to be closed thus preventing water loss and extending battery life. 

The first grid alloys used were lead alloys with 11% antimony content called hard lead . These alloys were replaced with low-antimony lead alloys with additions of Sn, As and Ag. Later, battery grid manufacturers switched to lead—calcium and lead—calcium—tin alloys. 

Table 4.4 summarises the effects of As on the mechanical properties of low-antimony lead alloys [21]. Arsenic improves the hardness and less so the UTS of the alloys. If these data are compared with the required grid alloy characteristics presented in Table 4.1, it can be seen that lead alloys with addition of arsenic meet the requirements of the battery industry with regard to hardness and their tensile strength is close to the required values. 

The influence of selenium and sulfur as refiners on the grain size of low-antimony lead alloys has been studied. The obtained results are presented in Fig. 4.21 [34]. 

The data in the figure indicate that rolling improves the mechanical properties of Pb—Ca—Sn materials. The alloys with a Ca content of 0.025 wt% reach maximum values of the mechanical parameters at 1.5 wt% Sn level. Alloys with higher Ca concentrations (0.05 and 0.07 wt% Ca) improve their mechanical properties with the increase of the Sn content up to 2.5 wt%. The mechanical parameters of rolled high-tin Pb—Ca—Sn alloys have values close to those of cast high-antimony lead alloys. Examinations of the microstructure of rolled Pb—Ca—Sn samples evidence particle orientation in the rolling direction. 

Antimony/lead alloys are used in bearings and electrical cable sheathing. 

Also included in Lead Operations are a lead allo3rs plant, a copper products plant, and an effluent treatment plant. The lead alloys plant produces arsenic-lead and antimony-lead alloys from the treatment of softener slag and silver refinery baghouse dust. The copper products plant produces copper sulphate, copper arsenate and sodium antimonate fi"om the treatment of copper matte and refinery baghouse dusts. The effluent treatment plant treats effluents from the zinc and lead operations as well as surface runoff from throughout the metallurgical operation. 

Secondary lead is recovered either as soft lead or as hard or antimonial lead. The metallic components of automobile batteries such as plate grids and posts may be made from antimonial lead alloys containing up to ten per cent antimony, but usually less than three per cent. This provides the source of antimony in secondary lead, but it can be controlled to some extent by separately processing metallics and non-metallic scrap. There is a trend to the use of calcium lead alloys in place of antimony for sealed batteries, which significantly reduces the quantity of antimonial lead prodnced by secondary smelters. 

Smelter revenues are also boosted by an ability to recover and sell by-products such as sulfuric acid and copper, as weU as some minor elements such as antimony in the form of antimonial lead alloys, mercury and cadmium. In some instances zinc can be recovered from smelter slags by fuming. 

Up to the 1970s the secondary industry was often small scale and localised in major population centres for ease of collection of used automotive batteries. It was also oriented to the return of the lead produced to the battery manufacturers. This was not difficult since most batteries used antimonial lead alloy for the grid material and hence the secondary smelter could recover both antimonial lead and soft lead, which could be suitably blended for return to the battery manufacturers. Since that time there have been significant changes, as follows ... 

A significant part of any refinery can be the various processes required to treat drosses and residues produced from each of the separate refining steps for the purpose of recovering by-products, recovering lead for recycle, or rendering the material suitable for disposal. Such processes include the conversion of copper dross into a marketable form for copper recovery, the production of silver and gold, the recovery of zinc for recycle, the recovery of antimony to produce antimonial lead alloy and the conversion of arsenic into a stable material suitable for disposal. 

Antimony present in smelter feed reports primarily to bullion, with smaller amounts in slag, and in any matte or speiss formed. It is the major impurity in secondary lead where it is sourced from antimonial lead alloys used in lead-acid batteries. 

Antimony is oxidised preferentially to lead, and hence is removed by oxidation with air or oxygen in the softening process or by sodium nitrate used with sodium hydroxide in the Harris process. The litharge slag from softening can be reduced to form an antimonial lead alloy, and the caustic slag from the Harris process can be treated to produce sodium antimonate. 

Bullion commonly contains np to two per cent arsenic. Arsenic is preferentially oxidised in the softening or Harris processes, bnt more readily than antimony. Conseqnently when softener slag is reduced to form an antimonial lead alloy, arsenic can be retained in the residual slag from where it can be extracted by leaching and precipitation as arsenic trioxide or as calcium arsenite. Alternatively it can be extracted from canstic slags from the Harris process by leaching and precipitation with lime as calcium arsenite, which can contain around 20 per cent As. 

For the typical lead smelter the principal by-products will be silver and gold, copper dross, sulfuric acid and antimony metal, usually in the form of antimonial lead alloy. Other possibilities are arsenic compounds and zinc oxide if slag fuming facilities are installed. 

Antimonial-lead alloys are the main additional by-product, but returns depend on local demand and the particular alloys required, and are difficult to quantify in a general way. With the popularity of calcium-lead alloys for sealed, maintenance free batteries, the price of aniimonial alloys declined, but has resurged due to increased demand for specialised batteries. Clearly this market is quite volatile. 

C. L. Luke "Photometric Determination of Tin with Fhenylfluorone. Deternoination of Tin in Lead and 1% Antimony-Lead Alloys" Anal. Chem. 

The maximum charging voltage is relevant to the current collector and grid material. Research has shown that when using an antimony lead alloy as grid material. 

ANTIMONY OXIDE. SbPy Mol wt 291.52 sp. gr. 5.2-5.7 very slightly soluble in water. Derived principally from stibnite, which is mined in western United States, China, Mexico and Bolivia. The oxide also is produced by the oxidation of antimony metal or as a byproduct in the refining of antimonial-lead alloys. 

The most important of the lead alloys is undoubtedly antimonial lead. For many years it has been a key component in battery manufacture, although it has faced increasing competition trom lead calcium alloys in this use (see Chapter 12). Antimonial lead alloys also have widespread application in the chemical industry for the manufacture of pumps, valves and other components, in radiation shielding and in several other uses. These alloys contain between 1 and 12 per cent antimony large toimages have traditionally been produced from re-melted lead, rather than from refined lead. 

---