MNG 230
Introduction to Mining Engineering

8.5.1: Overview of the Phosphate Industry

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8.5.1: Overview of the Phosphate Industry

Phosphate is a key component in agriculture (food production)

  • granular mono ammonium and diammonium phosphate pellets for fertilizer
  • animal feed supplements
  • elemental phosphorous for food-additive applications.

A limited amount of elemental phosphorus is used in other industrial applications.

In 2015, Phosphate rock was mined by 5 companies at 11 mines:

  • in 4 states
    • 80% in Florida and North Carolina & 20% in Idaho and Utah
  • to produce 27 million tons of marketable product with a value of $2.4 billion fob mine

World Mine Production and Reserves (USGS Minerals Commodity Survey)

2013 & 2014 mine production, and reserves, by country
Country Mine Production, 2013 Mine Production, 2014 Reserves
United States 31,200 27,100 1,100,000
Algeria 1500 1500 2,200,000
Australia 2600 2600 1,030,000
Brazil 6000 6750 270,000
Canada 400 --- 76,000
China 108,000 100,000 3,700,000
Egypt 6500 6000 715,000
India 1270 2100 35,000
Iraq 250 250 430,000
Israel 3500 3600 130,000
Jordan 5400 6000 1,300,000
Kazakhstan 1600 1600 260,000
Mexico 1760 1700 30,000
Morocco and Western Sahara 26,400 30,000 50,000,000
Peru 2580 2600 820,000
Russia 10,000 10,000 1,300,000
Saudi Arabia 3000 3000 211,000
Senegal 800 700 50,000
South Africa 2300 2200 1,500,000
Syria 500 1000 1,800,000
Togo 1,1110 1200 30,000
Tunisia 3500 5000 100,000
Vietnam 2370 2400 30,000
Other Countries 2580 2600 300,000
World Total (rounded) 225,000 220,000 67,000,000

There are three sources of Phosphate Rock

  • Sedimentary deposits of marine origin
    • Africa, China, Middle East, and United States
  • Igneous and metamorphic deposits
    • Brazil, Canada, Finland, Russia, and South Africa
  • Biogenic deposits from bird guano

High-quality sedimentary phosphate deposits are mined in the U.S.

The mined phosphate rock is beneficiated by a process in which the phosphate rock is reacted with sulfuric acid to produce an intermediate feedstock of phosphoric acid.

Gangue minerals associated with the deposit impact the cost of processing the ore

Clays and silica are the only significant gangue minerals in these high-quality deposits Carbonates are present in significant amounts in lower-quality deposits

The gangue minerals can require larger quantities of reactants (sulfuric acid), which significantly increases production costs, and can increase time require for downstream processing, e.g., filtration; and they can interfere with the ore recovery and concentration in downstream operations, e.g., float processes.

Carbonates are more problematic. Dolomite, for example, shares mineralogical similarities with phosphate, and this makes it more challenging and expensive to remove it.

  • Major gangue minerals of primary interest in U.S. operations:
    • dolomite, calcite, silica, and clays
  • Certain other gangue components may need to be removed during or after the production of the phosphoric acid:
    • cadmium, radium, uranium
  • Clay slimes are removed in log washers or hydrocyclones.
  • Silica is removed using the well-established Crago double float process.