Antimony content

Sodium Antimonate. Sodium antimonate [15593-75-6] Na SbO, another antimony synergist of commercial importance, has an antimony content of 61—63 wt % and a bulk density of 39.4—46.4 kg/m. Properties are given in Table 2. It is made by oxidizing antimony trioxide using sodium nitrate and caustic. It is a white powder and has a pH of around 9—11 when dissolved in water. 

Reverberator Furnace. Using a reverberatory furnace, a fine particle feed can be used, the antimony content can be controlled, and batch operations can be carried out when the supply of scrap material is limited. However, the antimony-rich slags formed must be reduced in a blast furnace to recover the contained antimony and lead. For treating battery scrap, the reverberatory furnace serves as a large melting faciUty where the metallic components are hquefted and the oxides and sulfate in the filler material are concurrently reduced to lead metal and the antimony is oxidized. The furnace products are antimony-rich (5 to 9%) slag and low antimony (less than 1%) lead. 

Antimony content, wt % Yield strength after aging, MPa "- Tenshe strength, MPa Elongation, %... 

Fig. 3. Grain size as a function of antimony content A, without grain refiners B, with addition of selenium (4).

By using nucleants, fine-grained stmctures, such as that shown in Figure 4b, can be produced in cast alloys independent of the antimony content. The molten metal must be kept at a temperature high enough to assure complete solubiUty of the nucleants prior to casting the alloy. In the United States primarily copper and sulfur are used as nucleants in Europe and Asia selenium is used. At very low (1.0—1.6 wt %) antimony contents selenium is used exclusively. 

The antimony content of commercial ores ranges from 5 to 60%, and deterrnines the method of treatment, either pyrometaHurgical or hydrometaHurgical. 

Antimony Alloys. Approximately one-half of the total antimony demand is for metal used in antimony alloys. Antimonial lead is a term used to describe lead alloys containing antimony in proportions of up to 25%. Most commercial lead—antimony alloys have antimony contents less than 11%. The compositions of several important antimony alloys are given in Table 4. 

Trace quantities of arsenic are added to lead-antimony grid alloys used ia lead—acid batteries (18) (see Batteries, lead acid). The addition of arsenic permits the use of a lower antimony content, thus minimising the self-discharging characteristics of the batteries that result from higher antimony concentrations. No significant loss ia hardness and casting characteristics of the grid alloy is observed (19,20). 

Greater amounts of copper increase the proportion of needles or stars of Cu Sn in the microstmcture. Increase in antimony above 7.5% results in antimony—tin cubes. Hardness and tensile strength increase with copper and antimony content ductiUty decreases. Low percentages of antimony (3—7%) and copper (2—4%) provide maximum resistance to fatigue cracking in service. Since these low alloy compositions are relatively soft and weak, compromise between fatigue resistance and compressive strength is often necessary. 

APPLICATION OF SURFACE ELECTROCHEMICAL PASSIVATION OF LEAD-ANTIMONY ALLOY FOR A SIMPLE AND RAPID ELECTROCHEMICAL DETERMINATION OF ANTIMONY CONTENT OF ITS ALLOYS... 

The closest relative to the wood veneer surprisingly has retained some of its properties, which differentiate these separators from pure synthetic ones primarily, a positive effect in reducing the water loss in starter batteries [39, 70-72], This impact tends to decrease as the antimony content in the alloys is lowered, but it still represents an advantage over other leaf separators, unless a microporous pocket is required by the alloy anyway. 

Therefore, passivation of the positive electrode by poorly conducting PbS04 can be reduced [348]. The porosity is important because it enables the expansion during the solid phase volume increase, which accompanies the transformation of Pb02 to PbS04. In the most popular construction, the electrode paste material (mixture of metallic lead with lead oxides) is held in a framework composed of lead alloys with additions of tin, antimony, selenium, and calcium [348]. Antimony improves the mechanical stability however, it increases the resistance and facilitates the selfdischarge of the battery. Better results are obtained for low antimony content and/or for lead-calcium alloys [203]. Methods of positive electrodes improvement, from the point of view of lead oxide technology have been discussed [350]. Influence of different factors on life cycle, nature, and composition of the positive active mass has been studied by Pavlov with coworkers [200, 351, 352]. 

The degree of change in and rj increases with antimony content (see the corresponding figures). Apart from this, the addition of Sb to a-Se shifts the crystallization onset to higher exposure values. 

TABLE 1. ANTIMONY CONTENT OF REPRESENTATIVE ANTIMONY-CONTAINING ALLOYS... 

Antimony contents are moderate to very high compared with the contents of Imperial coins. Four coins from the middle of the second century... 

B.C. contain very high antimony concentrations, and two of these are sem-isses (only four semisses were analyzed). The coins from the earliest period to about 160 B.C. contain moderate amounts of antimony (see Figure 9). Most of the coins made from around 160 to 80 B.C. have relatively high antimony contents these same coins also were relatively high in silver. The latest two coins have the very low antimony contents typical of coins minted in the early Roman Empire. 

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