Dolomite-ammonium nitrate

The resulting AN solution may be handled in various ways103. It can be stored as a solution, used in down-stream plants or sold as a solution it can be formed into solid AN by prilling or granulation, or it can be mixed with a solid filler. The most common filler is calcium carbonate in the form of ground limestone, dolomite or by-product calcium carbonate. This product is known as Calcium Ammonium Nitrate (CAN) and can be prilled or granulated. Granular products that contain AN and either ammonium or calcium sulphate are also manufactured. 

The droplets crystallize and condense into hard, spherical prills that are dried, cooled, and sized for shipment. If calcium ammonium nitrate (CAN or nitro chalk) is made, ground calcium carbonate (limestone or dolomite) is added to the melt prior to the formation of the droplets when CAN is being made103 10S. 

For safety reasons, solidified ammoitium nitrate should not be broken up by blasting. Products containing ammonium nitrate must be stored separately from oxidizable and inflammable materials and, if ammonium nitrate must be heated (during production, evaporation, etc ), the quantity must be kept small and catalysts avoided. In several countries, inert materials snch as limestone powder, dolomite, or precipitated calcium carbonate, are added to ammonium... 

Compound fertilisers (including calcium nitrate and calcium ammonium nitrate) sometimes contain 1 to 2 % of dolomitic hydrated lime. The lime confers similar benefits to pulverised dolomitic limestone (see section 10.3). 

When ammonium nitrate is used as straight material, the nitrogen content ranges from 30% to 34.5%. If it is mixed with milled limestone of calcitic or dolomitic type to make CAN, the nitrogen content is usually in the... 

CAN is produced by mixing concentrated ammonium nitrate solution with ground calcitic or dolomitic limestone, chalk marl, or precipitated calcium carbonate from nitrophosphate production. The mixing should be done quickly to avoid deccxnpoation of the ammonium nitrate ... 

Even unpolluted rain can contain both acids and bases. For example, carbon dioxide naturally present in air dissolves in rain to form carbonic acid (H2CO3), the weak acid responsible for the fizz in soda pop. If there were no other substances in rain, CO2 would lower the acidity from neutral (pH 7.0) to weakly acidic (pH 5.6). Unpolluted rain also contains small amounts of acid sulfate and acid nitrate that are produced in the stratosphere. These acids would further lower the natural pH of rain to about 5.4. Several alkaline substances partly neutralize the acidity in rain Ammonia, which is naturally present in the air, dissolves in rain to form ammonium salts. Soil dust containing alkaline minerals such as limestone (calcium carbonate) and dolomite (magnesium carbonate) can dissolve in rain and raise its pH. Fly ash from coal combustion contains calcium and magnesium oxides, which also are alkaline. The pH of rain therefore reflects the competing influence of several different substances. 

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