Soda Ash
In Singapore

Characteristics		IS 251 : 1998  specifications	TCL-assured specifications	Units
Molecular weight			106
Bulk density		500 – 750	550 – 720	Kg/m3
Volatile matter content (at the time of packing)		2	0.80	%, max
Total alkalinity (as Na2CO3)		98.5	99.0	%, min
Sulphates (as Na2SO4)		0.08	0.03	%, max
Chlorides (as NaCl)		1.0	0.80	%, max
Iron (as Fe2O3)	By colorimetric method		0.0029	%, max
	By spectrophotometric method	0.007	0.002
Matter insoluble in water		0.15	0.03	%, max

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/bi-sulfite 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.

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.

In addition, it is the most widely used fixed alkali for the manufacture of other alkali products, sodium salts, glass, soap, sodium silicates, detergent, bicarbonates, bichromates, cellulose and rayon, iron and steel, aluminum, cleaning compounds, textiles and dyestuffs, drugs and many other materials. It is also used as an alkali for household purposes and as washing powder by laundries.