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Caustic Soda Billing

Billing Formula

billing formula
billing formula

The total cost for shipped material (e.g., $/ton, 76% Na2O basis) is then computed by multiplying the net tons (or net kilos) of TA (76% Na2O basis) by the current price/ton. Note: The "76% Na2O basis" includes all titratable sodium, not just NaOH.

History of Sodium Oxide (Na2O) Basis

In North America, standard industry practice is to price and bill caustic soda on a sodium oxide {Na2O} basis. This originated in the late 1800's as lye (caustic soda) production grew out of the soda ash {Na2CO3} industry. Soda ash was reacted with calcium hydroxide {Ca(OH)2} to produce lye.

formula to create lye

The soda ash industry expressed the activity of their product on a Na2O basis. This concept was carried over to the lye industry. However, since this soda ash process to lye was only 98% efficient, the lye contained unreacted soda ash. Instead of 77.5 pounds of Na2O for every 100 pounds of total alkalinity only 76 pounds of Na2O (titratable NaOH and Na2CO3) was possible. The standard, therefore, was to bill for 76 pounds of Na2O for every 100 pounds of alkalinity and the term "76% Na2O basis" evolved.