ORIGINATION, INC.
Screening Magnesium Oxide Quality by Reactivity Test
Screening Magnesium oxide (MgO) and mineral sources is recommended by a simple, efficient and inexpensive test
method for evaluating the reactivity. The following method utilizes the time required for neutralization to take place
between mineral particles and an acidic solution. Jesse Goff of West Central Milling lists a simple method that measures
the rate of solubility (time) in a weak acid- (white distilled vinegar) measuring the increase in pH to 30 minutes.
Commercially available MgO sources can vary widely in biological availability: depending on origin of the precursor,
impurity concentration, degree of calcination, and particle size. It is found that the quality, solubility in particular, of
light burnt MgO could vary so much that the workability and performance of magnesia-based final products can be
significantly different between sources.
The following test method by Origination analyzes Magnesium Oxide reactivity, based on the Jesse Goff method. In
triplicate 100 ml beakers 3 grams of magnesium oxide and 40 ml vinegar are stirred continuously on a stir plate,
measuring pH for 30 minutes.
The most soluble MgO sources will increase pH to 7 and greater to pH 8-9 and the least soluble sources will remain at
pH 4-5. According to the results shown in figure 1, Origination Magnesium Oxide is favorably reactive and soluble with
increased pH to 9 in 30 minutes.
9.5
8.5
7.5
pH
6.5
5.5
Magnesium Oxide Sample 1
4.5
Magnesium Oxide Sample 2
Magnesium Oxide Sample 3
3.5
2.5
0
5
10
15
20
25
30
Time, Minutes
Figure 1: Vinegar Reactivity Test Method
1300 McKnight Road North | Maplewood, MN 55119 | 1-800-625-6079 | www.OriginationO2D.com
12/10/14