Lead-antimony system

The lead-antimony system has the simple eutectic type of phase diagram (Fig. 15.7). The regions are labeled L signifies liquid, Sb or Pb signifies pure solid antimony or pure solid... 

The lead-base babbitts ate based upon the lead—antimony—tin system, and, like the tin-base, have a stmcture of hard crystals ia a relatively soft matrix. The lead-base ahoys ate, however, mote prone to segregation, have a lower thermal conductivity than the tin-base babbitts, and ate employed genetahy as an iaexpensive substitute for the tin-base ahoys. Properly lined, however, they function satisfactorily as beatings under moderate conditions of load and speed. 

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... 

BOULANGERITE. A mineral compound of lead-antimony sulfide, PbjSb Sn. Crystallizes in the monoclinic system hardness, 2.5-3 specific gravity, 6.23 color, lead gray. 

GEOCRON ITE. A mineral sullide of lead, antimony and arsenic. Phs-ShAsS. Crystallizes in the monoclinic system. Hardness, 2.5 specific gravity. 6 4 color, gray to blue with metallic luster opaque. 

The pore volume and pore surface-area as a function of pore radius for an active mass formed from 3BS paste on lead-antimony grids are presented in Fig. 3.29(a) and (b), respectively. The pore volume begins to rise at a pore radius of 1 pm and the surface area at a pore radius of 0.1 pm. Pores with 0.1 pm radius have a specific pore volume of 0.065 cm g , which is about 62% of the total pore volume. The surface area of the pores of this same size is only 6% of the total surface-area of the PAM. These results demonstrate that the macrostructure of the PAM is basically built up of pores with radii larger than 0.1 pm (macro-pores), and these pores serve as the main transport system for the flows of ions and H2O between the bulk of the solution... 

A closer examination of hazardous waste characteristics of battery materials does reveal differences between battery chemistries. The toxicity of conventional battery materials such as lead, antimony and cadmium are well known, and therefore they are usually recovered as much as possible rather than disposing of them. Strict emission controls are required to prevent their release into the air or water. The problems with advanced battery systems in this regard are not quite so severe, but there still may be reactive, corrosive, or toxic materials present that must be dealt with during the recycling process. 

Ecjuilibrium Phase Diagram and Microstructure of the Lead—Antimony Alloy System... 

High levels of antimony can still be found in some old houses, probably due to the old lead-piping systems as well as layers of lead paints that contain antimony. 

However, it was found that still there may be high levels of antimony in some old houses, probably due to antimony containing lead piping systems and layers of antimony containing lead paints. 

Also secondary battery systems exhibit a broad range of different rates of selfdischarge. Their values, however, are based on a 1-month period in contrast to primary systems (1-year period). Depending on system and construction typical values vary between 2% and 30% per month at ambient temperature. For the lead-acid system the values vary between 2% and 20% per month depending on antimony content and age. The lithium-ion system offers about 5% to 10% per month. Values in the range of 20% to 30% per month are observed for the nickel cadmium and the nickel metal hydride system. 

A lead battery is an accumulator in which the electrodes consist primarily of lead, while a diluted sulfuric acid is used as an electrolyte. The lead is used in the form of bivalent and quadrivalent compounds (PbS04 and Pb02) and as a porous lead sponge for active masses, as well as in the form of lead-antimony or lead-calcium alloys for grids in lead batteries. The level of use of lead batteries in the portable appliance market is low. The main areas of application are starter and drive batteries as well as for uninterrupted power supply to stationary systems. 

The use of lead alloy (traditionally lead-antimony, with 5 per cent or less antimony) for the inert grids is based on the metal s excellent corrosion resistance, alloying capability and castability, and the benefits it imparts in paste to grid adhesion. Due to these properties, and its relatively low cost, lead remains a highly suitable material for the manufacture of efficient and competitive battery systems, despite its weight. 

Tin exists in two ahotropic forms white tin (P) and gray tin (a). White tin, the form which is most familiar, crystallizes in the body-centered tetragonal system. Gray tin has a diamond cubic stmcture and may be formed when very high purity tin is exposed to temperatures well below zero. The ahotropic transformation is retarded if the tin contains smah amounts of bismuth, antimony, or lead. The spontaneous appearance of gray tin is a rare occurrence because the initiation of transformation requires, in some cases, years of exposure at —40° C. Inoculation with a-tin particles accelerates the transformation. 

Catalytic Oxidation. Catalytic oxidation is used only for gaseous streams because combustion reactions take place on the surface of the catalyst which otherwise would be covered by soHd material. Common catalysts are palladium [7440-05-3] and platinum [7440-06-4]. Because of the catalytic boost, operating temperatures and residence times are much lower which reduce operating costs. Catalysts in any treatment system are susceptible to poisoning (masking of or interference with the active sites). Catalysts can be poisoned or deactivated by sulfur, bismuth [7440-69-9] phosphoms [7723-14-0] arsenic, antimony, mercury, lead, zinc, tin [7440-31-5] or halogens (notably chlorine) platinum catalysts can tolerate sulfur compounds, but can be poisoned by chlorine. 

A.sahi Chemical EHD Processes. In the late 1960s, Asahi Chemical Industries in Japan developed an alternative electrolyte system for the electroreductive coupling of acrylonitrile. The catholyte in the Asahi divided cell process consisted of an emulsion of acrylonitrile and electrolysis products in a 10% aqueous solution of tetraethyl ammonium sulfate. The concentration of acrylonitrile in the aqueous phase for the original Monsanto process was 15—20 wt %, but the Asahi process uses only about 2 wt %. Asahi claims simpler separation and purification of the adiponitrile from the catholyte. A cation-exchange membrane is employed with dilute sulfuric acid in the anode compartment. The cathode is lead containing 6% antimony, and the anode is the same alloy but also contains 0.7% silver (45). The current efficiency is of 88—89%, with an adiponitrile selectivity of 91%. This process, started by Asahi in 1971, at Nobeoka City, Japan, is also operated by the RhcJ)ne Poulenc subsidiary, Rhodia, in Bra2il under Hcense from Asahi. 

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