AquaResources has developed a new process for the manufacture of high purity magnesium hydroxide, Mg(OH)2 with desirable properties for various industrial applications. Extensive comparative analyses have been conducted, both chemical and physical to illustrate the properties of the AquaResources product.
Direct comparisons were made among a sample taken directly from the AquaResources manufacturing process (AR3-1-05-1), a spray dried sample of the same AquaResources product, (AR3-05-D), and an industry standard slurry supplied by Huber Corporation (AR3-1-05-2). The blind tests were run using recognized and certified laboratories. Detailed reports are shown in the appendices.
The results of the chemical analyses are shown in Table I. Samples AR3-05-1 and AR3-05-2 were oven-dried before analysis.
TABLE I
Analysis of Mg(OH)2 and Impurities (Wt%)
(Reports Appendix 1)
|
SAMPLE |
AR3-05-1 |
AR3-05-2 |
AR3-05-D |
|
|
|
|
|
|
Mg(OH)2 |
99.5 |
99.0 |
99.5 |
|
Moisture |
92.9 |
36.0 |
2.7 |
|
Calcium |
0.0078 |
0.286 |
0.0099 |
|
Chloride |
0.130 |
0.171 |
0.114 |
|
Iron |
0.0612 |
0.0451 |
0.0673 |
|
Silica |
0.192 |
0.162 |
0.178 |
|
Sodium |
0.014 |
0.0084 |
0.033 |
|
Sulfate |
negligible |
negligible |
negligible |
The AquaResources sample, 05-1, though it has only 7% solids, is a highly viscous gel compared to the 64% solids slurry of sample 05-2, the industry standard. Pictures are shown in Appendix 8.
Electron micrographs of the various samples were run by MVA Scientific Consultants. Results and micrographs are shown in Appendix 2 and Appendix 3. The Aqua gel sample (05-1) shows up as small nanometer size platelets, agglomerated into micron sized clusters. The spray dried sample shows rounded particles probably formed by aggregates of the platelets in a drying liquid droplet. The structure of 05-2 is completely different. The individual particles seem to have a cubic derived structure, arranged in conglomerates.
The extreme differences in crystal morphology between the AquaResources samples and the standard are further illustrated by the determination of surface areas, as reported in Appendix 4.
The two AquaResources samples have similar surface areas, 100 and 125 m2/g, while the standard has a surface area approximately one tenth as much at 11.5 m2/g, possibly indicating that the standard particles are larger.
The similarity in the surface areas of the gel and spray dried samples indicates that the spray drying does not change the size of the ultimate particles. In fact, the data in Appendix 5 may indicate that particle size and yield may be influenced by the drying. An economic estimate of the drying process is illustrated in Appendix 6.
AquaResources has developed a method for the manufacture of high-purity, high surface area magnesium hydroxide. The individual particles are platelets in the tens of nanometer sizes, loosely agglomerated into micron sized clusters. The particle size does not change with spray drying. The crystal structure and macro properties of the slurries obtained from the process are different from any other formulation of Mg(OH)2 we have found. The product forms a persistent gel at less than 7% solids.
Further research will include:
1. Increasing separation efficiency to reduce the percentage of impurities, most of which are in the liquid phase.
2. Changing reaction conditions to generate either larger or smaller particles, depending on the commercial requirements.
3. Increasing process efficiency.
4. Discovering the most economical conditions for generating the product and spray drying.
Submitted by
Dr. William Halpern PhD
Professor of Chemistry, Retired