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Light soda ash is a white, odourless,
uniform product, free from dirt and other foreign matter.
Physical and chemical properties
Soda ash has
a tendency to absorb moisture from the atmosphere. The moist soda ash then starts absorbing atmospheric carbon dioxide. This
phenomenon of absorption of moisture and carbon dioxide by soda ash is known as weathering. After weathering, soda ash is
likely to contain appreciable moisture and sodium bicarbonate, but the total alkali content of the bag does not change. Soda
ash has a tendency to cake when it comes in contact with moisture and, consequently, becomes lumpy.
Chemical formula: Na2CO3
O
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Structural formula: Na -- O -- C -- O -- NA
Common names:
Sodium carbonate, calcined soda, disodium carbonate
CAS registry number:
497-19-8
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Characteristics |
IS 251 : 1998 specifications
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RTC-assured specifications
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Units |
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Molecular weight |
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106 |
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Bulk density |
500 – 750 |
550 – 720 |
Kg/m3 |
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Volatile matter content
(at the time of packing) |
2 |
0.80 |
%, max |
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Total alkalinity (as Na2CO3) |
98.5 |
99.0 |
%, min |
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Sulphates (as Na2SO4) |
0.08 |
0.03 |
%, max |
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Chlorides (as NaCl) |
1.0 |
0.80 |
%, max |
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Iron
(as Fe2O3) |
By colorimetric method |
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0.0029 |
%, max |
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By spectrophotometric method |
0.007 |
0.002 |
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Matter insoluble in water |
0.15 |
0.03 |
%, max |
Applications
Light soda ash is one of the most
important basic industrial chemicals. Light soda ash is used to regulate pH in many chemical process streams. The superior
buffering capacity of soda ash versus caustic soda offers advantages in adjusting plant wastewater pH ranges.
Soda ash is used as the sodium source
for sodium sulfite/bisulfite pulping liquors used in the sulfite, CMP, and CTMP processes, and in NSSC pulping.
It is also possible to replace a portion of the caustic
soda in many pulp bleaching applications such as caustic extraction or hydrogen peroxide bleaching of mechanical or chemical
pulps. However, the higher pH requirements of these applications may necessitate the continued use of some caustic soda.
Packaging: Available in 50-kg HDPE / PP bags and
750-kg PP jumbo bags with lamination / liner.
Storage: Soda ash should be stored under cover
in a cool, dry place and the bags should not be stacked more than 15 bags high.
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