Comparison of flame retardant properties of magnesium hydroxide and aluminum hydroxide: the secret of reducing cable costs by 50%

With the rapid development of new energy, rail transit, 5G communications and other industries, the flame retardant properties and cost control of cables have become the core battlefield of industry competition. When traditional aluminum hydroxide flame retardants face the bottleneck of high filling volume and limited processing temperature, magnesium hydroxide is setting off a cost reduction revolution for cable materials with its high thermal stability, low smoke characteristics and synergistic efficiency-enhancing ability-some companies have measured a reduction of more than 50% in the comprehensive cost of cables, and the technical logic behind it is worth digging deeper.

1. Process economics of decomposition temperature

The decomposition temperature of magnesium hydroxide is as high as 340℃, which is more suitable for modern cable high-speed extrusion process than aluminum hydroxide (180-200℃). Taking XLPE (cross-linked polyethylene) cable as an example, its processing temperature usually needs to reach 220-250℃. If aluminum hydroxide is used, the flame retardant will decompose prematurely during the high-temperature extrusion process, which will not only lead to a decrease in flame retardant efficiency, but also cause material foaming due to water release, and the qualified rate of finished products will be reduced to below 80%.

Magnesium hydroxide remains stable in this temperature range, allowing companies to increase production line speed by 30%24. A transformation case of a cable company in East China shows that after replacing magnesium hydroxide-based materials, the daily production capacity of a single production line increased from 12 kilometers to 16 kilometers, and the energy consumption cost per kilometer decreased by 18%.

2. Cost disruption of filling amount

Traditional aluminum hydroxide needs to be added by more than 60% to meet the UL94 V-0 standard, which directly leads to two major cost pain points:

Substrate loss: High filling amount squeezes the space of polymer molecular chains, forcing companies to use expensive resins with higher melt index (MI>20g/10min);

Equipment wear: A large amount of inorganic particles aggravates the wear of screws and barrels, and the replacement cycle of key components of extruders is shortened from 3 years to 1.5 years.

Magnesium hydroxide achieves a revolution in filling volume through triple technological breakthroughs:

Surface modification: Silane coupling agent coating increases the particle dispersion uniformity by 60%, and 40% addition can achieve the same flame retardant level;

Nano-scale compounding: 500nm modified magnesium hydroxide and micron-grade aluminum hydroxide are compounded in a ratio of 1:3, and the synergistic flame retardant efficiency is increased by 40%;

Smoke suppression and efficiency enhancement: The smoke density (Dm) during combustion is only 1/3 of that of aluminum hydroxide, eliminating the cost of additional smoke suppressants (saving 800-1200 yuan per ton of wire).

3. Reconstruction of the cost of the entire life cycle

In the cost model of a new energy cable company in Jiangsu, the cost reduction effect brought by magnesium hydroxide runs through the entire chain of materials-production-operation and maintenance:

Raw material procurement: The price per ton of modified magnesium hydroxide is 15% lower than that of high-end aluminum hydroxide, and 20% recycled materials can be added;

Process optimization: The processing temperature is increased to 240°C, the cross-linking time is shortened by 25%, and the unit energy consumption is reduced by 22%;

Waste recycling: The combustion residue magnesium oxide can be directly reused as filler, and the recycling value of waste wire skin is increased by 40%;

Certification premium: The premium rate of cable products certified by EN 45545-2, TUV, etc. is 20-35%.

The company's 2024 financial report shows that the gross profit margin of photovoltaic cables using the magnesium hydroxide system has jumped from 18.7% to 29.3%, and the cost advantage is directly converted into market competitiveness.

4. Chemical code of synergistic effect

The cost-reduction miracle of magnesium hydroxide is inseparable from the "golden combination" with other flame retardants:

Red phosphorus synergy: Adding 2% microcapsule red phosphorus, the oxygen index is increased from 32% to 38%, and the filling volume is further compressed to 35%;

Zinc borate synergism: 3% zinc borate increases the residual carbon rate to 45%, forms a ceramic protective layer during combustion, and reduces the total demand for flame retardants;

Carbon nanotube conductive path: 0.5% carbon tube network improves the conductivity of the material, eliminates the risk of static ignition, and saves the cost of antistatic agent.

This "low main agent + high synergy" formula design has enabled a special cable company to successfully reduce the cost of flame retardant modules from 27% to 13%.

5. Hidden benefits of green manufacturing

The implementation of the EU CBAM carbon tariff has made the environmental protection attributes of magnesium hydroxide a new variable in cost accounting:

Carbon footprint advantage: From ore mining to finished product delivery, the carbon emissions of magnesium hydroxide process are 40% lower than those of aluminum hydroxide;

Simplified wastewater treatment: The decomposition product MgO can neutralize acidic waste gas, and the cost of waste gas treatment is reduced by 50%;

Recycling premium: No dehalogenation treatment is required when recycling magnesium-containing wire skin, saving 1,200 yuan per ton of recycled material processing fee.

Calculations by a multinational cable group show that after using the magnesium hydroxide system, the hidden environmental cost per kilometer of cable is reduced by 62%, avoiding the payment of 8% carbon tariffs in the EU market.

The endothermic decomposition of magnesium hydroxide has quietly built a triple line of defense - cooling, oxygen suppression, and smoke isolation. But this is not only a victory for materials science, but also a precise cost calculation: from the molecular-level optimization of nano-modification to the millisecond-level increase in production line speed, every technical detail is reshaping the profit formula of the cable industry. Driven by the dual goals of carbon neutrality and cost reduction and efficiency improvement, this flame retardant revolution led by magnesium hydroxide is pushing Chinese manufacturing to a new high in the value chain.