Comparison and cost analysis of production processes of ultra-pure magnesium hydroxide for cable materials
With the rapid development of new energy, rail transit and smart grid industries, the demand for ultra-pure magnesium hydroxide for cable materials as an environmentally friendly flame retardant continues to grow. Its high purity and low impurity characteristics can effectively improve the flame retardant properties and mechanical strength of cables. However, the choice of production process directly affects product quality and production costs. This article will analyze the technical route, advantages and disadvantages comparison and cost structure of mainstream production processes to provide reference for enterprise selection
1. The core role of ultra-pure magnesium hydroxide in cable materials
Ultra-pure magnesium hydroxide (Mg(OH)₂) has a high decomposition temperature (above 340°C) and strong thermal stability. It can release water vapor and absorb heat in high temperature environments to inhibit cable combustion. At the same time, its decomposition product magnesium oxide is non-toxic and harmless and meets EU RoHS, REACH and other environmental protection standards. It has become the preferred material to ｒｅｐｌａｃｅ traditional halogen flame retardants
However, cable materials have extremely high requirements for the purity of magnesium hydroxide (usually ≥99.5%) and need to control the content of impurities such as chloride ions and iron ions to avoid affecting the insulation performance of cables. Therefore The degree of refinement of the production process directly determines the market competitiveness of the product.
II. Comparison of mainstream production process technology routes
Currently, the methods for industrial production of ultra-pure magnesium hydroxide mainly include hydrothermal method, precipitation method and gas phase method. The three processes differ significantly in technical maturity, product purity and cost investment.
1. Hydrothermal process
- Process flow: high-purity magnesium oxide or magnesium chloride is used as raw material and is obtained through hydrothermal reaction, filtration, washing, drying and crushing.
- Advantages:
- Product purity can reach more than 99.8% and the impurity content is low.
- Crystal form is controllable and particle size distribution is uniform. It is suitable for high-end cable materials.
- Mild reaction conditions are suitable for large-scale production.
- Disadvantages:
- High equipment investment (high-pressure reactor is required)
- High energy consumption and high production cost
- High difficulty in wastewater treatment and high environmental pressure.
2. Precipitation process
- Process flow: magnesium salt (such as magnesium chloride, magnesium sulfate) reacts with alkaline solution (sodium hydroxide or ammonia water) to generate precipitate, which is then washed and dried to obtain the finished product.
- Advantages:
- Simple equipment Low initial investment
- Mature process, suitable for small and medium-sized production enterprises
- Wide source of raw materials, controllable cost
- Disadvantages:
- Low product purity (usually 98%-99%), multiple washings are required to improve purity
- High risk of impurity residues, affecting cable performance
- High salt content in wastewater, increased treatment costs
3. Gas phase process
- Process flow: Direct synthesis of magnesium hydroxide by high-temperature gas phase reaction of magnesium vapor and water vapor
- Advantages:
- Extremely high product purity (≥99.9%), near zero impurity content
- No washing steps required, excellent environmental performance
- Suitable for the production of nano-magnesium hydroxide
- Disadvantages:
- Complex equipment, demanding technical requirements
- Extremely high energy consumption, production cost is 2-3 times that of hydrothermal method
- Large-scale industrial application has not yet been achieved
III. Comparative analysis of production costs
The cost structure of different processes is significantly different. The following is a typical cost structure of each process (taking an annual production scale of 10,000 tons as an example):
| Cost item | Hydrothermal method | Precipitation method | Gas phase method |
| ---- | ---- | ---- | ---- | ---- |
| Raw material cost | 40%-45% | 50%-55% | 30%-35% |
| Energy cost | 25%-30% | 15%-20% | 45%-50% |
| Equipment depreciation | 15%-20% | 10%-15% | 25%-30% |
| Environmental treatment | 10%-12% | 15%-18% | 5%-8% |
| Labor and others | 5%-8% | 5%-10% | 5%-10% |
Key conclusions:
- The comprehensive cost of the hydrothermal method is relatively high, but the product has a strong premium ability and is suitable for the high-end cable material market
- The precipitation method has the lowest cost, but it needs to balance purity and environmental protection investment, which is suitable for mid- and low-end applications
- The gas phase method is limited by equipment and energy consumption Currently only applicable to special demand scenarios
IV. Industry application cases and trends
1. Case reference:
- A Japanese company uses hydrothermal method to produce 99.8% pure magnesium hydroxide for high-voltage cables of new energy vehicles. The price is 30% higher than that of precipitation method products
- A Chinese manufacturer improves the precipitation process (adds ion exchange steps) to increase the purity to 99.3%, successfully enters the mid-end cable material supply chain, and reduces costs by 15%
2. Future trends:
- Green process upgrade: Develop low-energy hydrothermal reaction technology to reduce the energy consumption of high-pressure reactors
- Resource recycling: Extract magnesium sources from brine and salt lake waste liquid to reduce raw material costs
- Nano-development: Improve the dispersibility of magnesium hydroxide in cable materials through surface modification and reduce the amount of addition
V. Summary and suggestions
The selection of ultra-pure magnesium hydroxide production process needs to be combined with the company's positioning:
- The high-end market gives priority to hydrothermal method to obtain premium through high-purity products
- The mid-end market can optimize the precipitation process to balance cost and quality
- Long-term layout recommends focusing on the technical breakthrough of gas phase method to seize the opportunity of nano-level products
In addition Enterprises need to pay attention to environmental protection investment, reduce comprehensive costs through wastewater recycling, waste heat utilization, etc., and strengthen technical cooperation with cable material manufacturers to develop customized adaptation products to enhance market competitiveness