How to Choose Magnesium Oxide: A Comprehensive and Practical Purchasing Guide
Step 1: Define the Core Application Area (The Most Important Prerequisite)
Before considering any technical parameters, you must first answer one question: What am I buying magnesium oxide for? The application area directly determines which indicators you need to focus on.
Pharmaceutical and Food Grade: Used for antacids, magnesium supplements, food additives, etc. Core requirements are high purity, low heavy metal content, and compliance with pharmacopoeia or food standards.
Industrial Grade: Used as a filler and flame retardant in rubber, plastics, coatings, etc. Focus on particle size, whiteness, iodine adsorption value, and compatibility with the base material.
Silicon Steel Grade: Used for coating oriented silicon steel sheets. This is the most high-end requirement, with extremely strict demands on purity, activity, and particle size distribution.
Refractory Grade: Used for manufacturing magnesia bricks, metallurgical furnace linings, etc. Core indicators are magnesium oxide content, sintering degree, bulk density, and hydration resistance.
Agricultural and Feed Grade: Used as a soil amendment or animal feed additive. Requires low heavy metal content and attention to the bioavailability of magnesium.
Environmental Protection Grade: Used for wastewater treatment, flue gas desulfurification, etc. Requires attention to purity, reactivity, and specific surface area.
Step 2: Focus on Key Performance Indicators
After defining the application area, you need to focus on the following key technical indicators:
1. Purity (MgO Content)
How to choose:
Pharmaceuticals, food, silicon steel, and other fields require the highest purity, typically needing to reach 95% - 99% or above.
Industrial fillers and refractory materials can choose products with moderate purity based on specific formulation requirements to control costs.
2. Activity (Reactivity)
How to choose:
High Activity Magnesium Oxide (Iodine Adsorption Value > 120): Suitable for scenarios requiring fast reactions, such as environmental wastewater treatment, chloroprene rubber vulcanization, etc.
Medium Activity Magnesium Oxide (Iodine Adsorption Value 40-120): Commonly used as an activator and promoter in ordinary rubber and plastics.
Low Activity Magnesium Oxide (Iodine Adsorption Value < 40): Subjected to dead burning or hard burning, it has low activity and good hydration resistance, mainly used for refractory materials, electrical materials, etc.
3. Particle Size and Particle Size Distribution
How to choose:
Fine Particle Size (e.g., above 800 mesh): When used as a filler, it can disperse better in the base material, improving the smoothness and mechanical properties of the product.
Uniform Particle Size Distribution: Helps to increase packing density, which is particularly important in the preparation of refractory materials and ceramics.
Antacids for pharmaceutical use have specific requirements for particle size to control their reaction rate in the stomach.
