General Description
White odorless solid. Sinks and dissolves in water.
Reactivity Profile
AMMONIUM SULFATE(7783-20-2) is acidic in aqueous solution. When a little AMMONIUM SULFATE(7783-20-2) is added to fused potassium nitrite, a vigorous reaction occurs attended by flame [Mellor 2:702 1946-47].
Air & Water Reactions
Dissolves in water with evolution of some heat.
Chemical Properties
White crystalline powder
Physical properties
White crystalline solid; orthorhombic crystal; density 1.769 g/cm3 at 20°C; melts between 511 to 515°C (in a closed system): however, in an open system, it melts with decomposition at 280°C; readily dissolves in water (solubility, 70.6 g and 104 g per 100 g water at 0°C and 100°C, respectively); insoluble in acetone, alcohol and ether.
Occurrence
Ammonium sulfate occurs in trace concentrations in the upper atmosphere. It is widely used as a fertilizer for rice and other crops. It is a source of sulfur for the soil. It is also used as an additive to supply nutrient nitrogen in fermentation processes (e.g., yeast production from molasses). It also is used for fireproofing timber and plastics, and in treatment of hides, and leather production.
Definition
ammonium sulphate: A whiterhombic solid, (NH4)2SO4; r.d. 1.77;decomposes at 235°C. It is very solublein water and insoluble in ethanol.It occurs naturally as the mineralmascagnite. Ammonium sulphatewas formerly manufactured from the‘ammoniacal liquors’ produced duringcoal-gas manufacture but is nowproduced by the direct reaction betweenammonia gas and sulphuricacid. It is decomposed by heating torelease ammonia (and ammoniumhydrogensulphate) and eventuallywater, sulphur dioxide, and ammonia.Vast quantities of ammoniumsulphate are used as fertilizers.
Production Methods
Ammonium sulfate is a high-tonnage industrial chemical, but frequently may be considered a byproduct as well as intended end-product of manufacture. A significant commercial source of (NH4)2SO4 is its creation as a byproduct in the manufacture of caprolactam, which yields several tons of the compound per ton of caprolactam made. Ammonium sulfate also is a byproduct of coke oven operations where the excess NH3 formed is neutralized with H2SO4 to form (NH4)2SO4. In the Meresburg reaction, natural or byproduct gypsum is reacted with ammonium carbonate: CaSO4·2H2O + (NH4)2CO3 CaCO3 + (NH4)2SO4 +2 H2O The product is stable, free-flowing crystals. As a fertilizer, (NH4)2SO4 has the advantage of adding sulfur to the soil as well as nitrogen. By weight, the compound contains 21% N and 24% S. Ammonium sulfate also is used in electric dry cell batteries, as a soldering liquid, as a fire retardant for fabrics and other products, and as a source of certain ammonium chemicals.
Flammability and Explosibility
Notclassified
Agricultural Uses
Ammonium sulphate, (NH4)2SO4, a water-soluble
crystalline salt is a nitrogenous fertilizer containing about
2 1 % nitrogen and 24 % sulphur. It occurs naturally as the
mineral mascagnite and offers many advantages as a
fertilizer, such as low hygroscopicity, good physical
properties, excellent chemical stability, good agronomic
effectiveness and long shelf life.
Ammoniacal nitrogen is fned in the soil in an
exchangeable form until nitrated by nitrifying bacteria.
The ammoniacal nitrogen of ammonium sulphate does
not leach out easily. Ammonium sulphate is an acid
forming fertilizer, and hence used in neutral or alkaline
soils. In its free flowing form, it is directly applied to the
soil or blended with other granular materials.
Ammonium sulphate also supplies sulphur, which is an
essential nutrient for plants.
Ammonium sulphate is a quick-acting fertilizer. It is
resistant to leaching as it gets adsorbed on the soil
colloids, clay and humus, and replaces calcium. This
adsorbed ammonium salt is converted to nitrate by
nitrifying bacteria for use by growing plants.
Ammonium sulphate is produced in different ways,
The major ones are: (i) Production from synthesized
ammonia and sulphuric acid.
(ii) Production of ammonium sulphate fertilizer by the
gypsum process is widely used in many developing
countries. In this process, ammonia is used along with
pulverized calcium sulphate, carbon dioxide and water.
Here ammonia made from nitrogen and hydrogen, reacts
with carbon dioxide gas to produce ammonium
carbonate. Ground gypsum reacts with ammonium
carbonate solution to form ammonium sulphate and
calcium carbonate.
Ammonium sulphate is commonly transported in
polythene or paper bags. It is adsorbed on soil colloids,
clay and humus, replacing calcium. It is more beneficial
than nitrate fertilizers at planting time. This adsorbed
portion is slowly released and in about a month most of
the ammonium sulphate is converted into the nitrate
form, which is used by growing plants.
Since rice crops absorb nitrogen even in the
ammoniacal form, ammonium sulphate fertilizer is used
as a source of nitrogen for rice in the USA and Southeast
Asia. In the USA, ammonium sulphate is also used for
potato scab control.
The main disadvantages of ammonium sulphate are its
acid forming nature, low nitrogen percentage
(21%) and high costs for packaging, storage and
transportation.
Biochem/physiol Actions
Ammonium sulfate?((NH4)2SO4) is mainly used as a soil fertilizer. It is also used as a wood preservative. This inorganic salt plays a role in flame retardant chemicals.
Purification Methods
Crystallise it twice from hot water containing 0.2% EDTA to remove metal ions, then finally from distilled water. Dry it in a desiccator for 2 weeks over Mg(ClO4)2. After 3 recrystallisations, ACS grade had Ti, K, Fe, Na at 11, 4.4, 4.4, 3.2 ppm respectively.
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