Manganese addition

CA ARB 1999. Manganese additive content. California Air Resources Board. 26 CCR 13-2254. 

Bacha, R. E. and L. R. Hossner. 1977. Characteristics of coatings formed on rice roots as affected by iron and manganese additions. Soil Sci. Soc. Am. J. 41 931-935. 

The usual alloying additions to aluminum in order to improve physical properties include Cu, Si, Mg, Zn, and Mn. Of these, manganese may actually improve the corrosion resistance of wrought and cast alloys. One reason is that the compound MnAle forms and takes iron into solid solution. The compound (MnFe)Alg settles to the bottom of the melt, in this way reducing the harmful influence on corrosion of small quantities of alloyed iron present as an impurity [27]. No such incorporation occurs in the case of cobalt, copper, and nickel, so that manganese additions would not be expected to counteract the harmful effects of these elements on corrosion behavior. 

Manganese additions increase the strength of unalloyed aluminium (Fig. 3.1-23). The chemical resistance is not impaired. These alloys have very good forming properties, when the Mn content is below the maximum solubility of Mn in the Al-rich a-phase, i. e., practically below 1.5 wt%. At higher Mn content, brittle AlgMn crystals form and impair workability. 

Fig. 3.1 -23 Effect of manganese additions on the strength of aluminium alloys based on 99.5 wt% Al, quenched from 565 °C, sheet samples, 1.6mm thick [1.23]...

The industrial chemical treatment of tungsten concentrate uses scheelite, either concentrated scheelite or synthetic scheelite, manufactured from woframite concentrates. In this latter case wolframite is treated with sodium hydroxide or sodium carbonate to form sodium tungstate. Dissolution in water and filtering removes the hydroxides of iron and manganese. Addition of calcium chloride to the filtrate precipitates calcium tungstate - synthetic scheelite. 

In addition to providing somewhat increased stability over the manganese addition and equivalent ductility, somewhat higher yield strengths are observed at all test temperatures. 

Fig. 15. Dependence of T3 DNA directed SAMase synthesis on Mg + and Mn + concentration. SAMase synthesis was performed in the DEAE system as described in Table 2. Synthesis was allowed to proceed at various concentrations of MgClg or MnClg. In the cases of manganese addition a basal concentration of 5 mM MgClj.was present in all samples because the system itself had been prepared with TMA buffer...

---