World Resources, Mine Production and Ore Concentration

Molybdenum is, as mentioned, present as molybdenite MoSj as an associated sulfide in copper deposits and as the principal sulfide in large low-grade porphyry molybdenum deposits. The reserve base amounts to about 11 milHon tonnes (counted as molybdenum) in the whole world, half of which is in the USA. These resources are enough to supply world needs for the foreseeable future. 

Mine production was 129000 tonnes (of molybdenum) in the year 2000 [25.2]. The countries with the greatest outputs (thousand tonnes) were the USA (41.1), Chile (29.1), China (28.9), Peru (7.2), Mexico (6.9), Canada (6.83), Armenia (2.7), Russia (2.4) and Iran (1.6). 

The large-scale use of molybdenum in modem industry rests on mass mining of large deposits of low-grade ores. The concentration of these in an economical way has been made possible by an effective ore dressing with flotation (see Chapter 1 Introduction). The separation processes are complicated, especially from Mo-containing 

After crushing and grinding the ore is subjected to flotation and a combined Cu-Mo sulfide concentrate is obtained. In a second flotation process the two sulfides are separated and the copper concentrate goes to copper production. 

During the roasting of Mo sulfide, sulfur dioxide is formed from which sulfuric acid can be produced in modern plants. If SO is allowed to leave the chimney freely it has disastrous effects on the environment. 

---