Phosphates Odda process

Most of the nitric acid is utilized in the form of 50 to 70% acid for the manufacture of nitrogen-containing fertilizer, particularly ammonium nitrate. Ammonium nitrate is also used as an explosive e.g. in mining, due to its low explosion temperature (safety explosive). Other industrially important nitrates are sodium nitrate, a speciality fertilizer and oxidizing agent in the glass and enamel industries, and calcium and potassium nitrates, which are also used as fertilizers. Nitric acid is also utilized in the digestion of raw phosphate (Odda process, which is not operated in the USA, see Section 2.1.2.4) ... 

The two commercially important nitrophosphate processes differ in the way they solve the problem of phosphate water solubility caused by the presence of calcium nitrate in the slurry resulting from the reaction of phosphate rock vnth nitric acid. The first process, historically, is the Odda process wherein calcium nitrate is precipitated and separated. Tlie mixed acid process does not separate the calcium nitrate the phosphate water solubility is increased by adding phosphoric acid to decrease the CaO P205 ratio. 

Nitrophosphate products, either granular or prilled, contain calcium in the NP(K) grades and in the ammonium nitrate coproduct (see Chapter 13). NPK grades such as 13-13-13 retain some of the calcium originally in the PR because the calcium nitrate is neyer completely removed in the Odda process crystallization step. The re ual calcium is converted primarily to dicaldum phosphate when ammoniation is carried out to produce the NPK products. Tlie separated crystalline calcium nitrate is dissolved and converted to ammonium nitrate solution and solid calcium carbonate by addition of ammonia and carbon dioxide. The ammonium nitrate solution... 

Inorganic fertilizer is often synthesized using the Haber-Boseh proeess, whieh produees ammonia as the end produet. This ammonia is used as a feedstoek for other nitrogen fertilizers, sueh as anhydrous ammonium nitrate and urea. These eoneentrated produets may be diluted with water to form a eoneentrated liquid fertilizer. Ammonia ean be eombined with roek phosphate and potassium fertilizer in the Odda Process to produee eompound fertilizer. 

Odda A process for making a fertilizer by treating phosphate rock with nitric acid. Developed by Odda Smelteverk, Norway, in the early 1900s and still in use in 1988. Licensed by BASF and offered by Uhde. 

The phosphoric acid invention was also an outcome of the Hafslund Group s own strategy. In 1922 - before starting Odda Smelteverk - Hafslund considered the possibility that the Odda factory might produce new fertilisers that contained both nitrogen and phosphate, based on French processes. Hafslund was thus part of a... 

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