Ammonium phosphates are derived from a reaction of ammonia and phosphoric acid and they are nearly totally used as fertilizers. Less than 3% of the world consumption is used in industrial applications and animal feed. DAP, diammonium phosphate, is the main solid phosphate fertilizer. Its excellent handling properties and N-P-K composition 18-46-0 make it well suited to both large- and small-scale agriculture. The production of one tonne of DAP requires 0.23 tonnes of ammonia and 1,175 tonnes of phosphoric acid 40% P2O5 (0.470 tonnes P2O5). Actually this means that the production of one tonne of DAP requires almost one tonne of the fourth element, sulphur. The DAP trade is the dominant element in the phosphate scene, heavily influencing production and prices, some 35-40% of the global output of phosacid is used in DAP manufacture. More than 40% of the global production of DAP is traded across borders, much more than ammonia, but significantly less than potash. DAP is widely used in bulk blending. The production of 1 tonne MAP, monoammonium phosphate, typically 11-53-0, requires 0.15 tonnes of ammonia and 1.35 tonnes of phosphoric acid 40% P2O5. MAP is produced in both granular and non-granular form, the latter being used in the production of granular NPK and suspension fertilizers.
June 12, 2015 at 16:14 (Fertilizers)
Sulphur is a key raw material for the fertilizer industry and its single largest end use is in the manufacture of phosphate fertilizers in the form of sulphuric acid. Sulphur is also used in the production of carbon disulphide, sulphur dioxide and phosphorous pentasulphide; pulp and paper uses; and rubber vulcanizing. Agronomically, sulphur is an essential element in forming protein, vitamins, enzymes, and chlorophyll in plants, and nodule development in legumes. It has been called the “fourth nutrient” and in 2014 China was its main consumer, followed by the United States.
World sulphuric acid supply is of some 250 Mt H2SO4, and it is produced from sulphur, oxygen and water via the contact process. The major growth drivers for sulphuric acid are the global consumption of phosphoric acid, titanium dioxide, hydrofluoric acid, ammonium sulfate manufacture, and for uranium processing and metallurgical applications.
Crops have different sulphur sensitivities: alfalfa, canola, and clover are very responsive to sulphur, while cereal crops such as wheat and corn are less responsive.
Soil with less than one percent organic matter is prone to sulphur deficiencies; soil with greater than 5 % organic matter is usually unresponsive to sulphur. Sulphur deficiency is usually seen when the soil has less than 10 ppm of soluble sulphur, and it has a retarding effect on plant growth.
Elemental sulphur has at least 85% S, and there are different types of fertilizers also containing sulphur: ammonium sulphate has some 24% S, ammonium thiosulphate 26%, SSP 12%, magnesium sulphate 14%, potassium sulphate 18%, potassium thiosulphate 17%, sulphur coated urea 10% S. Elemental sulphur is also used as a pesticide or fungicide.
Sulphur is commonly incorporated to both granular compound fertilizers and bulk-blended fertilizers in the form of AS, SSP, or calcium phosphate. Most of the fertilizer sulphur applied to soils comes from sulphate-containing fertilizers. But the most concentrated sulphur carriers are the fertilizers containing elemental sulphur.
Many NPK formulations contain sulphur, but the amount has decreased with the trend towards higher analysis fertilizers.
Plant requirements for sulphur are equal to or exceed those for phosphorus. It is one of the major nutrients essential for plant growth, root nodule formation of legumes and plants protection mechanisms. Sulphur application rates in typical fertilization practices usually range from 5 to 20 pounds of sulphur per acre.
For the production of 1 tonne of 100% H2SO4 sulphuric acid, they are required 0.33 tonnes of sulphur (or 0.76 tonnes pyrites 48% S).
Most of the sulphur production comes from the processing of fossil fuels, sulphur mined in its elemental form has declined over the last decade to less than two percent of world production.
Iron pyrites (FeS2) have typically 40-53% S, pyrrhotite minerals (Fe6S7) 40%, gypsum (CaSO4.2H2O) 19%, and anhydrite (CaSO4) 24%.
Around 90% of the global sulphur production is by-product and only some 10% is elective. The largest producers are China and the United States, followed by Russia and Canada.
The sulphur trade is dominated by the imports to China.
In 2014 China imported some 10.2 million tonnes S and the main suppliers were West Asia, eastern Europa and Central Asia, Japan, Canada, and the United States.
The Chinese sulphur imports are mainly geared to the southwestern provinces of Yunnan, Sichuan, and Guizhou, mostly for usage in the compound phosphate fertilizer factories. The majority of the Chinese sulfacid manufacturers are small producers. The pyrite process accounted for some 80% in the mid-nineties, but its proportion has been decreasing steadily since then, being less than half in the early current decade.
Resources of elemental sulphur in evaporite and volcanic deposits and sulphur associated with natural gas, petroleum, tar sands, and metal sulfides amount to about five billion tonnes. The main sulphur reserves are located in Canada, the United States, Poland, Iraq, China, Saudi Arabia, Mexico, Spain, Italy, France, Japan, and others. The sulphur in gypsum and anhydrite is almost limitless, and some 600 billion tonnes of sulphur is contained in coal, oil shales, and shale rich in organic matter, tar sands, but low-cost methods have not been developed to recover sulphur from these sources. The domestic sulphur resource is about one-fifth of the world total. Sulphur supplies should be adequate for the foreseeable future.
Toronto-headquartered Allana Potash Corp. is a junior mining company with a focus on the acquisition and development of potash assets internationally with its flagship in the Danakhil Potash property (also referred to as the Dallol Potash Project), which is a previously explored potash property in northeastern Ethiopia. Now Allana has announced the results from an independent preliminary economic assessment (PEA) of production of SOP (sulphate of potash), a premium potash product widely used on chloride sensitive crops such as tobacco, fruits and vegetables, as well as nuts. In 2014 world production was of some 2.7 million tonnes K2O. China is the largest consumer. SOP production would be a separate mining operation producing about 1 million metric tons per year over an estimated 77- year operating life through solution mining of brine followed by solar evaporation. The Danakhil Project area is the one of hottest places on earth, which allows for the use of solar evaporation after solution mining and should bring significant cost savings. It has been reported that Ethiopia is the cheapest place to extract potash after Jordan, because the deposits are only 100 meters below the surface, compared with about 1,000 meters in Brazil and Canada where the grade is similar. Total operating costs, including production, transportation, port storage and loading, and sustaining capital expenditures, are estimated at $130/mt of SOP. The payback period from the start of production is estimated at four years.
EuroChem, Russia-based global nitrogen and phosphate fertilizer producer, will in 2015/16 start the construction of a beneficiation plant in the Zhambyl province in southern Kazakhstan. The output will be send to phosphate plants in Southern Russia. As of 2014, the company had a total of 4.2 billion tonnes of phosphate rock reserves and resources and realized capital expenditures of US$ 282 million in phosphates. Kazakhstan has 260 million mt reserves of phosphate rock and produced in the last couple of years some 1.6 million tonnes rock per year. Eurochem plans to produce in the current year over 120,000 mt of finished phosphate. The development in Kazakhstan is strategically important for Eurochem because of the threat that further declines in iron ore price may reduce the phosphate segment economics at the company’s Kovdorskiy GOK.
India, the world’s second largest fertilizer consuming country, had on this decade an annual fertilizer consumption growth of 4.8 percent. The availability of raw material for indigenous production is poor. Urea is the only fertilizer that can potentially be produced without any imported content. But the paucity of natural gas, the most preferred feed stock for its manufacture, is coming in the way of doing so, necessitating the setting up of joint ventures for urea production in gas-rich countries. In the case of the other fertilizers, the country has no source of potash, and only limited resources of phosphate rock. India’s phosphate processing facilities are located along the coast to facilitate the imports of raw materials needed to produce upgraded phosphate products. India’s levels of rock imports are highly impacted by the situation of the country’s DAP inventories.
India has a great potential for fertilizer consumption growth because its soils are under considerable strain, the result of natural nutrient deficiencies, intense farming practices and diverse crop requirements.
Israel’s potash maker ICL has promoted a major step forward in the phosphate front. It is forming a j-v with the Chinese leading producer of phosphate rock and fertilizers Yunnan Yuntianhua by an investment of US$ 500 million. The Israelis will receive a 15% ownership of the Chinese company, which in 2013 had sales of 55.87 billion Chinese Renmimbi (US$ 9.02 billion). This was an increase of 465.1% versus 2012, when the company’s sales were 9.89 billion Chinese Renmimbi. The value of the Yunnan company’s phosphate chain accounts for some three quarters of their total gross profit.
The new j-v company will operate an integrated phosphate operation, based on an annual production of some 2.5 million tonnes of phosphate rock during the next 30 years, through the 100% ownership of the Haiko Phosphate Mines Assets. They will have a nameplate annual capacity of 700,000 tonnes of phosacid, 1.85 million tonnes of sulphuric acid, 60,000 tonnes of white phosphoric acid, 65,000 tonnes of speciality phosphates for the food and engineered materials market, and 850,000 tonnes of fertilizers. In this way, ICL will overcome her failure in developing the Barir phosphate field in Arad (Israel) due to environmental objections and secure for decades rock at a more competitive cost. ICL produced last year at its home base in the Negev 3.4 million tonnes rock, of which 946,000 were exported. Her main export market was India, where she sold 318,000 tonnes. Last year ICL also produced 576,000 tonnes of green phosphoric acid, 211,000 tonnes of white phosphoric acid, and 1.7 million tonnes fertilizers.
With the additional Yunnan phosphate capacities, ICL will be a more important mover in the phosphate scene, with some 6 million tonnes phosrock, 1,300 tonnes of phosacid, 350,000 tonnes of purified phosacid, 2.7 million tonnes of fertilizers and nearly 0.9 million tonnes of specialty fertilizers. The j-v will also give ICL new products like, for example, specialty water soluble MAP.
The phosphate rock main market is the production of phosphate fertilizer products such as ammonium phosphates and superphosphates, which accounts for some 90% of the world phosphate rock consumption. Phosphorous plays an important role in root development and in the synthesis of protein, fats and carbohydrates. The rest is consumed as animal feed and in a variety of industrial/technical applications (for phosphoric acid required for detergents and cleaners, food production, metal cleaning, etc.).
Sedimentary deposits provide between 80-90% of the world phosphate rock production, containing francolite–a carbonate-fluorapatite. Francolites with high carbonate for P substitution are the most highly reactive and the most suitable for direct application as fertilizers or soil amendments, but this usage is quite limited and it is estimated that world consumption is less than two million tonnes per annum. Some 10-20% of world phosphate production is mined from igneous deposits. Relative to sedimentary pebble rocks, igneous phosphates have a macrocrystalline structure and are denser and less porous. More than 30 countries produce phosphate rock for commercial purposes, with the top 12 countries supplying over 90% of all the material.
Lower grade rock undergoes a beneficiation process to remove impurities creating an improved quality product with higher phosphate content. The methods employed to beneficiate phosphate rock consist of washing, grinding, flotation (to isolate phosphate bearing ore from certain impurities) and drying. This beneficiation process usually yields a concentration of around 1.5 times, but higher ratios are possible with some rocks. The targeted result of the beneficiation process is a phosphate concentrate ranging from 28% to 35% P2O5.
There is a limited usage of phosphate rock applied directly as a fertilizer. The use of rock phosphate for direct application as fertilizer depends on its level of solubility in the acidic soil. This application is dependent up on the structure and chemical composition of the rock. Mineralogical tests should be done to assess the suitability for direct application. It is stated that carbonate radical is responsible for the reactivity of directly applied P2O5 in the rock.
Sometimes the rock is partially acidulated – called PAPR – a process that converts the insoluble tricalcium phosphate of phosphate rock into a mixture of water-soluble monocalcium phosphate and citrate-soluble dicalcium phosphate. The extent of acidulation depends on factors like the type of acid, acid-rock ratio, temperature, time of reaction, and the proportion of apatite and non-apatite materials in the rock. Different acids have been used and they include phosphoric acid, sulphuric, hydrochloric, nitric, carbonic, oxalic, citric and acetic acids.
The physical characteristics of a rock can sometimes limit its acceptability both for economic and environmental reasons. The hardness of a rock together with the particle size distribution and the type of grinding equipment used will determine the energy used in getting the rock fine enough for the processing stage. Hard rocks and those with angular silica grains increase substantially the wear on grinding equipment. The size distribution of the particles also affects the rock’s handling characteristics. Rocks with too many “fines” will be dusty causing P205 losses and environmental pollution. The water content of concentrates is generally kept above 1.5% to limit dusting and below 2.5% for economic shipping. The pore spacing of the rock also determines its handling characteristics, for instance igneous rock types have few pore spaces and may be saturated with moisture at only 1-2% H20.
The quantity of certain chemicals contained within a rock directly affects its usefulness for the manufacture of phosphoric acid and downstream fertilizers. As well as affecting the process directly, many of these constituents interreact to produce other effects, some beneficial, but mostly detrimental to the reaction. A key factor is the calcium sulphate content of the rock, the remaining CaO level will be directly related to the consumption of sulphuric acid. Seawater washing during rock beneficiation and insufficient freshwater rinsing can be a cause of high and fluctuating Cl levels. As an indication of carbonate levels in the rock, CO2 high values can indicate a tendency to foam during the reaction. Heavy metal content of phosphate products seriously impact the composition of animal feed and food grade products (for example the high cadmium content of the Togolese rock ouput, gravely affects its export possibilities).
Phosphate Rock Production
2012 = About 200 million tonnes rock
China is the biggest world producer of phosphate rock.
There is a historic trend by which the phosphate fertilizer manufacturing goes from areas lacking the raw material, to those who mine it. So it happens that if in the beginning of the seventies trade of phosphate rock neared half of its production, today it is around a tenth.
In world phosphate rock trade, the Moroccan governmental producer OCP (Office Cherifien des Phosphates) is the key player with more than a third of the world exports.
In 2011, the five largest rock importers were India, USA, Indonesia, Belgium and Brazil; in 2012 they were India, USA, Indonesia, Brazil and Poland.
Morocco has about a three quarters of the world phosphate rock reserves, they are the second world producer and the biggest exporter, accounting for more than a third of the world exports.
India is the largest world importer of phosphate rock, and Jordan is its main supplier.
A key indicator for the rock price levels are the DAP price developments:
The above chart uses prices of phosphate rock (Moroccan), 70% BPL, contract, f.a.s. Casablanca, and DAP, bulk, f.o.b. US Gulf.
Giant phosphate producer OCP and Brazilian fertilizer producer Fertilizantes Heringer have entered into a definitive agreement, under which OCP will purchase around a 10 percent stake in Heringer. Under the terms of the deal, Casablanca-based OCP will buy a minimum of 5,385,712 and a maximum of 5,686,316 new common nominative shares, or 9.5-10.5pc, of Heringer’s shares for USD 64.9m. The company’s production capacity increased from 5,7 million tonnes in 2011 to 6 million tonnes in 2013. OCP, the world’s biggest phosphate exporter, is claiming a stake in Brazil to take advantage of booming demand for fertilizers at a time when Mosaic and Yara are also snapping up assets, driving a consolidation in the industry.
Heringer will invest the proceeds gained from this sale in increasing its blending capacity in its key markets. Brazil is expected to supply in the current year some 32,1 million tonnes fertilizers, a volume 3.2% larger than in 2013. Soybean farmers, who buy about a third of the fertilizers used in the country, are expected to grow a record crop this year as Chinese demand for animal feed remains strong.