Chemistry Reference
In-Depth Information
phosphate rock were reported from Iraq, adding significantly to the total
known reserves.
Potash is mined at the rate of 25-30 million tonnes K
2
O annually. Just 12
countries produce 99% of the world's potash, with over 30% of production
derived from Canada, 50% from the USA and Canada combined, where over
90% of the world's reserves are located. There is no potash production of
significance from Africa, south/south-east Asia or Australasia. In contrast,
over 30 countries mine significant quantities of phosphate rock, in all
continents. China is the dominant producer. According to the Food and
Agriculture Organization of the United Nations (FAO), fertiliser production is
sufficient to meet demand from world markets.
11
At current rates of mining, declared reserves of K have a lifetime of between
200 and 400 years, and those of P have a lifetime of 400 years. In terms of their
life expectancy, estimated resources of K are equivalent to 7500 years, and of P
are equivalent to 1800 years, assuming production at current levels. Given
these figures, it is important to be cautious when considering the concept of
'peak phosphorus'.
12
Also, waste-waters represent an excellent potential source
of P that can be recovered for use as a fertiliser.
13
The price of fertilisers has been highly variable in recent years. Figure 3
shows changes in the price of diammonium phosphate (DAP), urea and KCl
fertilisers since 2000. The price of urea precisely tracks the price of Brent crude
d
n
1
r
2
n
g
|
3
Figure
3
Variation in prices of phosphorus (diammonium phosphate; DAP),
nitrogen (urea) and potassium (muriate of potash; MOP) fertilisers since
2000. (Source: plotted using data from the World Bank, April 2012, http://
databank.worldbank.org).
