Precipitated Mg(OH)2 Factory

Gansu Kaimeite (KMT) Materials Science and Technology Co., Ltd focuses on the research and development of precipitated magnesium hydroxide. Through the reaction between magnesium chloride and ammonia water

MgCl2 + 2NH3 ▪ H2O → Mg(OH)2 ↓ + 2NH4Cl

Every year we generate 30,000 tons of high-purity ultra-fine magnesium hydroxide and 10,000 tons of high-purity magnesium oxide;

Process Flow Chart of Precipitated Magnesium Hydroxide

KMT Magnesium Hydroxide

Flame Retardant Mechanism of Magnesium Hydroxide

Mg(OH)2 ———> MgO+H2O

When the temperature reaches 340℃, magnesium hydroxide starts decomposing and generating water and Magnesium oxide. The water will absorb heat and dilute the oxygen content in the air to stop the fire, while the magnesium oxide will adhere to the surface of the combustible material to stop the fire and also absorb toxic gas and smoke produced during the fire.

KMT Precipitated Magnesium Hydroxide

KMT Industrial high purity precipitated MDH is manufactured according to the below chemical reaction:

                MgCl2 + 2NH3 ▪ H2O → Mg(OH)2 ↓ + 2NH4Cl

First, we extract its main raw material directly from the saltwater to prepare the Magnesium Chloride solution, then the solution will go through a purification process to become the highly purified solution. After we get purified Magnesium Chloride solution, along with ammonia, two solutions will be added into the reactor and react under specific temperature. We will get coarse precipitated Magnesium Hydroxide.

Finally, based on customer request, coarse precipitated Magnesium Hydroxide shall go through hydrothermal modification and milled into different particle sizes’ powder and coated with different additives. The entire production process is environmentally friendly and pollution-free. Ammonium water is recyclable, and no toxic matter is generated. That is what KMT industrial insisted on from the very beginning.

Table 1 PM Series MDH Technical Data
Table 2 PM Series MDH Particle Sizes
GradesMedian Particle Sizes (D50)
PM32.5-3.5 μm
PM51-2 μm
Table 3 PM Series MDH Coating
SSSilane or composite additives coatedlow smoke zero halogen flame retardant material
SLProprietary composite additive coated
Other customized coatings  are also available

Table 3 shows available additives for coating. It makes the powder easy to disperse in the polymer and provides better mechanical properties. Silane and stearic acid coated MDH can improve the dispersity, flame retardant performance, and by adding special additive, the processing rheology is also improved because the compound viscosity is lowered. KMT also developed proprietary coating such as SL, SN, SM. Compared with silane coated MDH, SL, SN, SM coated MDH has a better elongation, MFI, and better charing.

KMT Precipitated Magnesium Hydroxide---Comparison Test Data

To identify the performance of PM series MDH, the KMT R&D center conducted several tests by adding different grade MDH into the EVA-based formula. On the one hand, to see the performance of PM3SL, PM5SN, and PM5SM, on the other hand, to compare KMT PM series MDH with MDH made by American, Japanese, and Russian company.

The results show that:

1. In terms of MFI, PM3SL has better performance than PM5SN.

2. KMT PM series can be an alternative for American, Japanese, Russian MDH.

3. PM series can all pass the UL94 V-0 test (3.2mm), see table 5.

Table 4  Polyolefin Test Formulation
Flame retardantsKMT PM3SL60     
KMT PM5SN 60    
KMT PM9SL  60   
American MDH   60  
Japanese MDH    60 
Russian MDH     60
PropertiesTensile strength (MPa)13.515.515.313.612.511.2
Elongation at break (%)170190205195211182
MFI  (g/10min, 5KG/190℃)
Oxygen Index (% , 100*6.5*3.2mm)33.534.73430.53030.5


UL94 Combustion Test Report

Table 5  UL94 Combustion Test
PM3SLV-0American MDHV-1
PM5SNV-0Japanese MDHV-1
PM9SLV-0V-0Russian MDHV-0


Differences of Flame Retardant ATH & MDH

1. When being heated, MDH and ATH both generate water and metal oxide. Water absorbs heat, and metal oxide covers the surface of polymer. But MgO can absorb more acid than Al2O3.

2. Magnesium hydroxide (MDH) degrades at 340℃, 140℃ higher than Aluminum Hydroxide (ATH) does, so MDH is better for plastics required high processing temperatures.

3. MDH dissociation energy is 1.37kJ/g; ATH dissociation energy is 1.05KJ/g, and the thermal capacity of MDH is 17% higher than ATH also. So MDH has higher flame retardant efficiency.

4. Magnesium hydroxide with more carbonization can reduce more smoke.

5. MDH particle is softer than ATH, so less abrasion will happen during the compounding process which is good for the compounding machine.

KMT Industry's Services Always Go Extra Mile

KMT Industry’s goal is to let you sit back and relax. We take care of all the dirty works, including trade stuff,  clearance and logistics, etc. Our consultant will keep you informed of the trade progress throughout.

Formular and polymer test Available

If you want a basic formula to compare with competitors grades, we can support it in our lab.

Lighting Fast Delivery

Normal grades have the inventory to support fast delivery.

Start With Low MOQ

If you want to have a trial test, we support a minimum order quantity of small kgs for the first order.

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