Antimony

What it is and where it is found
Antimony is a silvery, brittle metal which hardens the “soft” metals tin and lead and makes them more corrosion resistant. In nature antimony occurs in connection with sulphur and other elements, such as copper, lead and tungsten. Its melting point is 630.74°C, and the boiling point is 1,750°C. The density amounts to 6.697 g/cm³. Almost 80 % of the antimony deposits are located in the PR of China.  

What it is used for
Most antimony is processed in metallic form to produce pure ingots and alloys, such as hard lead, type metal and white metal (Pb-Sb alloys, Sn-Sb alloys), and after transformation into trioxide it is used in metallic-chemical form as fire-protection chemical.
These two fields of application together cover at least 80 % of total antimony consumption with variations from country to country.
Antimony in metallic form is used, for instance, in the production of starter batteries. The grades 99.5 % and 99.65 % (grade II) are mainly needed for making alloys, although material of 99.85 % purity (grade I) is also partly used for this purpose. Antimony of grade I is also required for oxide production in some cases. For Pb alloys grade II material is used, for Sn alloys grade I material.
There also are so-called ”off grades“, such as 90/10 – i.e. Sb about 92 %, Pb 7 %, As 1 %, but the Fe, Zn and Cu content has to be determined as it will decide about the applications for which the off grades suitable. Such material is supplied to the manufacturers of car starter batteries and within the steel industry.

How it is traded
Antimony is traded as 20 – 25 kg ingots of

• grade II with Sb min 99.65 %, As max 0.15 %, Se max 50 ppm

            and of    

• Sb trioxide (grade I) 

to which in addition the following limit values apply: Bi max 100 ppm

•     Cu max 200 ppm

•     Pb max  0,2 %

•     Fe max 200 ppm

or directly as trioxide.