Most of Yara's production sites are in Europe. Based on statistical information from the European Fertilizer Manufacturers Association (EFMA), Yara's management believes Yara has established a cost position below the average of other European producers.
Yara's low-cost position is also partly a result of its access to low-cost natural gas. Yara's joint venture investment in ammonia and urea manufacturing in the Middle East (Qatar) and the Caribbean (Trinidad and Tobago) is also based on the availability of low-cost natural gas in these areas.
In the nitrophosphate process used by Yara, nitric acid is used for digestion of the phosphate rock. This benefits the extraction of calcium by crystallization as calcium nitrate (CN), and processing of high-quality prilled or granular CN products.
The majority of manufacturing processes for complex fertilizers are based on dissolution of phosphate rock in mineral acid followed by neutralization, concentration and finally, granulation or prilling. In some processes, sulfuric acid is used for the dissolution of phosphates. The calcium originating from the rock is then extracted as gypsum, a waste material that can cause environmental problems.
Millions of years ago, igneous rocks were formed when cooled magma solidified beneath the surface of the earth’s crust. For tens of thousands of years, these crystallized phosphate rocks lay buried beneath layers of soil deposited during glacial periods.
Then in 1950, a worker in central Finland discovered the phosphate deposit at Siilinjärvi during the construction of a railway. The deposit at Sokli in the north of Finland near the Russian border was found in 1967 by a professional company carrying out a systematic exploration.
The deposits in Siilinjärvi and Sokli are carbonatite igneous rocks. The phosphate ore is called apatite. At Siilinjärvi the ore feed is hard rock, which has to be mined by drilling and blasting. Sokli’s ore feed is weathered rock – a type of loose soil or gravel – which can be partly excavated and partly blasted.
What's extra special about these ancient ore deposits – Siilinjärvi is more than 2600 million years old, while Sokli is 300 million – is that in terms of purity, they both offer the best phosphoric raw material available, containing only minute traces of hazardous heavy metals.
Today these millions-of-years-old minerals play a key role in the provision of food for a growing global population.
Operations in Siilinjärvi include phosphate mining and phosphoric acid production. In addition, there are potentially strategic phosphate ore reserves in Sokli.
During the apatite concentration process, the rock is crushed and milled and then further refined through flotation, thickening and filtration. This concentrates the hard rock ore feed, giving it the necessary phosphorus content for the production of phosphoric acid (from 9.16 percent phosphorus to 82.44 percent). The phosphorus content of rock is traditionally expressed as phosphorus pentoxide P2O5.
Then the apatite concentrate can be mixed with sulphuric acid to create phosphoric acid. Phosphoric acid can be used as a raw material in the production of fertilizer and feed phosphates, as well as in the manufacture of washing detergents, in the food industry and in biological water purification.