Neutralization
processing.
A chemical process, which allows the CO2 removal with
neutralization reaction per a basic reagent.
Main simplified formula: xOH- + CO2
>>> x[HCO3-]
NB: No action on calcium hardness (calcium is unchanged).
Note:
neutralization to be complete, does not continue until complete
disappearance of carbonic acid [CO2,
H2O] in the water: decision of neutralizing action is
to balance saturation of calcium carbonate [CaCO3]
water, or calcocarbonic balance.
If you continue to add reagent, then produce a softening by
precipitation of CaCO3 as it, in excess, can remain
solubilized and thus is deposited (in terms of concentration
reached). At this point, the residual CO2 is said balancing, and is
therefore considered more aggressive CO2.
Possible main practices (formulas) :
(click on name of the reagent for more information)
Notes: as regards fltration on limestone neutralization action is
relatively slow (relative to injection of reagents), and also
decreases the efficiency of progressively reducing the CO2
content; it is therefore necessary to provide substantial filters
(possibly see dimensioning programs
Neutral
and
Neutral-F
(in french) > link Hydro-Land
site).
Doses in mg of product (100% pure) for 1 mg of neutralized aggressive
CO2 (mg / mg or g/m3):
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Increased alkalinity (TAC), and total hardness (TH), according to the reagent employed (in °F / mg/L as CaCO3, per mg of removed CO2 ):
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Special case:
Neutralization with sodium bicarbonate ,
In this case there is a constancy of free CO2 content:
transformation of aggressive CO2 in free CO2, balancing and training
NaHCO3, thus increasing the Alkalinity (can go up the balance of
CaCO3 saturation).
Dose in mg of product (100% pure) 1 mg of for aggressive CO2
"transformed" (mg / mg or g/m3)
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Increasing alkalinity (TAC) and TH (° F / mg/L CaCO3, per mg of NaHCO3 injected)
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Reagents which act only on calcium hardness (no neutralization of
CO2):
Increasing hardness according to the employed reagent (mg of pure
anhydrous reagent to be injected for increased 1° F or 10 mg/L
as CaCO3):
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NB :
The doses shown are to100% reagent purity and it is necessary to
correct the dose taking into account the purity (100% pure reagent)
of commercial product.
CORRECTION OF DOSES BASED ON COMMERCIAL PRODUCT:
Quantity by mass (weight) of the commercial product:
Volume amount of commercial product:
So as,
EXAMPLES.
Example 1:
Dt theoretical dose of lime indicated = 30 g as Ca
[OH]2 / m³ of water
or,
Weight amount of commercial solid lime (Qm): (100/80 x 30)
= 37.5 g / m³ of water,
Amount by volume of lime solution (Qv): (1/1, 65 x 30) = 18.19
liters / m³ water.
Example 2 :
Dt theoretical dose of sodium carbonate Na2CO3 = 40 g/m³
deau,
or,
Amount by weight of trade sodium carbonate (Qm) : (100/96x 40 = 41.7 g/m³ deau,
Amount by volume of sodium carbonate
solution (Qv) : (1/50 x 40) = 0.8 liter / m³ water
(800 ml/m3)
Example 3 :
Dt theoretical dose of caustic soda NaOH = 25 g/m³
water,
Amount by weight of trade caustic soda (Qm) : (100/30x25 = 83.3 g/m³ water.
Amount by volume of trade caustic soda (Qv) : (1
/ 1328 x 83.3) = 0.0627 liter / m³ water (or
62.7 ml/m3).
...........................................................or (Qv) :
(1 / 398.4 x 25) = 0.0627 L/m³