Technical Information (PDF)

PHYSICAL PROPERTIES
LIQUID @ 60ºF

Molecular Weight: 278
Specific Gravity: 1.15 – 1.19
Lbs./Gal. FeSO4 Solution: 9.69
Lbs. Of FeSO4/Gal.: 2.86
Lbs. Fe/Gal.: 0.50 – 0.59
Crystallization Begins: 29ºF
pH: 1.5 – 2.2
Insolubles (As TSS): <0.5%

Ferrous Sulfate Solutions

General Information

In dissolving QC Corporation’s Dried Ferrous Sulfate Heptahydrate (Fe ~20%) or Moist Ferrous Sulfate (Fe ~18%) product in water, the following variables should be considered:

A. Temperature of water used
B. Content of water used
C. pH of water used

Experiments in dissolving Ferrous Sulfate have disclosed that distilled water, at a temperature of 60ºF., will become totally saturated with iron salts whenever ~33.3% by weight of dried Ferrous Sulfate Heptahydrate is added to ~66.6% by weight water. The resulting solution should weigh approximately 9.69 pounds per gallon. To achieve the same solution with Moist Ferrous Sulfate requires ~35.5% Moist Ferrous Sulfate by weight added to ~64.5% by weight water. In addition, this same solution should have a Baumé of 24.5, a specific gravity of 1.19, and contain ~19% FeSO4. The above calculations will vary with contents, pH and temperature of the liquid being used. Greater quantities of Ferrous Sulfate can be totally dissolved in water temperatures above 60ºF., and conversely, less Ferrous Sulfate can be totally dissolved in water temperatures below 60ºF. If a Ferrous Sulfate solution becomes over-saturated, the iron salts will begin to precipitate out and drop to the bottom of the container used.

An over-saturated solution can be further diluted, heated and treated with small quantities of sulfuric acid to totally re-dissolve the iron back into solution again.When physically dissolving Ferrous Sulfate Heptahydrate into a solution, it is suggested that a mechanical agitator be used, such as a “Lightnin” type mixer, to expose the crystals to the water solution before they have a chance to settle to the bottom of the mixing vessel. Another means of agitation can be the use of a recirculating pump to draw the solution from the bottom of the mixing vessel and returning it near the top as the Ferrous Sulfate is being added. Extreme agitation or the use of air generation should be avoided, as these methods would induce oxygen into the solution resulting in a chemical conversion of ferrous iron to ferric iron. Since most Ferrous Sulfate solutions have a pH of approximately 2, it is recommended that all handling equipment, including mixers, vessels, piping and pumps be made of synthetic, non-corrosive materials of construction, such as PVC or stainless steel.

The above information is to be used as a guide only. Each application of Ferrous Sulfate Heptahydrate should be evaluated on a case-by-case basis by trying to dissolve the material in solution, using various types of water or other solutions.

FERROUS SULFATE HEPTAHYDRATE SOLUBILITY

Temp.
°C/°F
Gm.
Gal.
Lbs./
Gal.
Lbs. Iron
(Fe)/Gal.
Specific
Gravity*
0/32 600.5 1.32 0.26 1.158
10/50 787.1 1.73 0.35 1.208
20/68 1014 2.23 0.45 1.268
30/86 1259 2.77 0.56 1.334
40/104 1545 3.40 0.68 1.411
50/122 1848 4.07 0.81 1.494

Accuracy ± 2%
*Calculated

PHYSICAL PROPERTIES OF AQUEOUS FERROUS SULFATE SOLUTIONS AT 68ºF

Specific
Gravity
Percent
FeSO4
Gm./Liter Lbs./Cu. Ft. Lbs./Gal.
0.1 1.0007 ~0.2% 2.001 0.1249 0.0167
0.4 1.0028 ~0.4% 4.011 0.2504 0.0335
0.7 1.0046 ~0.6% 6.028 0.3763 0.0503
0.9 1.0065 ~0.8% 8.052 0.5027 0.0672
1.2 1.0085 ~1.0% 10.09 0.633 0.0842
2.6 1.0180 ~2.0% 20.36 1.271 0.1699
5.2 1.0375 ~4.0% 41.50 2.591 0.3463
7.9 1.0575 ~6.0% 63.45 3.961 0.5295
10.6 1.0785 ~8.0% 86.28 5.386 0.7200
13.2 1.1000 ~10.0% 110.0 6.867 0.9180
15.8 1.1220 ~12.0% 134.6 8.405 1.1240
18.3 1.1445 ~14.0% 160.2 10.00 1.3370
20.8 1.1675 ~16.0% 186.8 11.66 1.5590
23.2 1.1905 ~18.0% 214.3 13.38 1.7880
25.5 1.2135 ~20.0% 242.7 15.15 2.0250

Specific
Gravity
Percent FeSO4
* 7H20
Gm./Liter Lbs./Cu. Ft. Lbs./Gal.
0.1 1.0007 ~0.37% 3.663 0.2287 0.0306
0.4 1.0028 ~0.73% 7.341 0.4583 0.0613
0.7 1.0046 ~1.10% 11.03 0.6887 0.0921
0.9 1.0065 ~1.46% 14.74 0.9200 0.1230
1.2 1.0085 ~1.83% 18.46 1.152 0.1540
2.6 1.0180 ~3.66% 37.26 2.326 0.3110
5.2 1.0375 ~7.32% 75.95 4.742 0.6339
7.9 1.0575 ~11.0% 116.1 7.249 0.9691
10.6 1.0785 ~14.6% 157.9 9.858 1.3180
13.2 1.1000 ~18.3% 201.3 12.57 1.6800
15.8 1.1220 ~22.0% 246.4 15.38 2.0560
18.3 1.1445 ~25.6% 293.3 18.31 2.4470
20.8 1.1675 ~29.3% 341.9 21.34 2.8530
23.2 1.1905 ~32.9% 392.2 24.48 3.2730
25.5 1.2135 ~36.6% 444.2 27.73 3.7070

QC’s Diamond Brand® Ferrous (Iron) Sulfate products are registered in Canada as a Pest Control Product (PCP) under the Canadian PCP Act.