As a flame retardant magnesium hydroxide(MDH) researcher, always I need to talk about this product for different persons, they may purchasing, boss, R&D, engineer, student, customers, or my colleagues. So I have an idea that I can write down it and help more people if it used for you, I will be much happy.

Flame retardant magnesium hydroxide have different type and grade, according to the production method, there will have precipitated grade MDH, mineral method MDH, Hydrothermal method MDH; According to the surface coated modification classification, there will have the uncoated grade, stearic acid surface coated, silane coated, composite additives coated;  According to particle size classification, will have 325 mesh, 1250 mesh, 2500 mesh, 5000 mesh, 10000mesh; (Regarding ‘mesh’, you can check in google for an easy reference, believe you will have a good understand) According to magnesium hydroxide crystal structure classification, will have hexagonal structure MDH, fiber structure MDH, flake structure MDH, fiber and flake mixing MDH.

1.According to the production method

1.1 Preparation principle of synthetic magnesium hydroxide:

Seawater extraction or salt lake water reaction with alkali;

Common preparation principles:

MgCl2+Ca(OH)2→CaCl2+Mg(OH)2↓;

MgCl2+2NH3·H2O→Mg(OH)2↓+2NH4Cl  (KMT XK series magnesium hydroxide adopts this preparation method);

The synthetic magnesium hydroxide obtained by chemical reaction has the characteristics of high purity, high whiteness, and few impurities. Processing performance and flame retardancy are better than ore-method magnesium hydroxide.

1.2 Hydrothermal method magnesium hydroxide

1.3 Ore method magnesium hydroxide (also called brucite powder)

The preparation principle of ore-method magnesium hydroxide:

Brucite ore mining-ore selection-jaw crusher for preliminary crushing-Raymond mill grinding-packaging and delivery

Brucite ore mining-ore selection-jaw crusher for preliminary crushing-Raymond mill grinding-vertical mill grinding-packaging and delivery

Brucite ore mining-ore selection-jaw crusher for preliminary crushing-Raymond mill grinding-jet mill grinding-packaging and delivery

Brucite ore mining-ore selection-jaw crusher for preliminary crushing-hammer crushing-packaging and delivery

Brucite ore mining-ore selection-jaw crusher for preliminary crushing-environmentally friendly calcination-packaging and delivery

Brucite ore mining-ore selection-jaw crusher for preliminary crushing-Raymond mill grinding-powder modification-packaging and delivery

2. According to the surface coated modification classification

2.1 Uncoated grade: original powder, non-coated.

2.2 Stearic acid surface coated: Use different types of stearic acid coated the powder surface, like using a high-speed mixer to finish.

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2.3 Silane surface coated: silane coating treatment on the surface of the powder (The effects of different silane additives will be quite different. I would like to share in detail in another article “Silane additives that can be used for surface modification of magnesium hydroxide”), use a high-speed mixer to complete the dry modification.

2.4 Composite additives coated

This one seems no need explanation, easy to understand.

3. According to particle size classification

325 mesh: D50>10 micron, representative grade XK-325 series

1250 mesh: D50: 6-7 microns, representative grade XK-1250 series

2500 mesh: D50: 5-6 microns, representative grade XK-2500 series

5000 mesh: D50: 2.6-3 microns, representative grade XK-5000/99 series

10000 mesh: D50=1-2 microns, representative grade XK-10000/99 series, MAGNIFIN H5, MAGNIFIN H5IV,

4. According to magnesium hydroxide crystal structure classification

4.1 Hexagonal flake magnesium hydroxide

The crystal photo shows a standard hexagonal plate, and the best-performing hexagonal plate has a very regular hexagonal shape control and a very uniform size. The thickness of the hexagonal plate is very suitable. For example, the picture below is a standard hexagonal sheet crystal form:

4.2 Fibrous magnesium hydroxide

The crystal structure is thick rod-like and fibrous; the mechanical properties are better in tensile strength and worse in elongation.

4.3 Flaky non-hexagonal magnesium hydroxide

Flakes, different sizes, not strictly hexagonal in shape, larger specific surface area. The processing performance is worse than regular hexagonal tablets.

4.4 Magnesium hydroxide with a mixed structure of flake and fiber

This one seems no need explanation, easy to understand.