Zinc powder: Characteristics, applications and industrial development of highly active metal powders

Zinc powder (Zn) is a light gray to dark gray metal elemental powder with a molecular formula of Zn, CAS number 7440-66-6, and a molar mass of 65.39 g·mol⁻¹. As a highly active powder material, it is insoluble in water and easily soluble in inorganic acids and alkali. With its excellent reducibility, conductivity and anti-corrosion properties, it plays a key role in anti-corrosion coatings, chemical synthesis, battery manufacturing and other fields. It is an important metal raw material connecting basic industry and high-end manufacturing. From anti-rust protection in traditional industries to functional upgrades in the new energy field, the industrial value of zinc powder continues to rise with technological iterations.
1. Core psychological properties: activity-dominated performance characteristics

The core performance of zinc powder comes from the synergistic effect of its metallic properties and powder form. The physical properties and chemical activity empower each other, which determines its application boundaries and safety requirements. In terms of physical properties, the relative density of zinc powder is 7.14, the melting point is 420°C, and the boiling point is 907°C. The particle size can extend from the micron level to the nanometer level. The smaller the particle size, the larger the specific surface area, and the stronger the chemical activity. Indicators such as powder fluidity and tap density change with the particle shape (spherical, flaky, needle-shaped). Among them, spherical zinc powder has excellent fluidity, while flaky zinc powder is more suitable for coating masking needs.

In terms of chemical properties, the most outstanding characteristic of zinc powder is its strong reducing property, which can react with acids and bases to release hydrogen. It is often used as a reducing agent in organic synthesis, such as reducing indigo dye in the printing and dyeing industry and achieving bleaching and decolorization in the oil industry. At room temperature, zinc powder is easily oxidized by oxygen in the air to form an oxide film. When it gets damp, it slowly reacts with water to produce high temperatures, which intensifies the activity decay. Special attention should be paid to the fact that when zinc powder dust reaches a certain concentration in the air, it will cause combustion or dust explosion when exposed to open flames, and emit blue flames when burning. This characteristic imposes strict safety requirements on its storage and transportation.

2. Preparation process: technological upgrading from large-scale to precise

The zinc powder preparation process is iterated around the three core goals of "controlling particle size, optimizing morphology, and improving purity", forming two major technical systems: industrial mass production and high-end customization. Different process products adapt to differentiated application scenarios, and industry leading companies have achieved import substitution of high-end products.

(1) Mainstream industrial preparation processes

1. Atomization method: Using high-purity zinc ingots as raw materials, the zinc is melted and then atomized and broken by high-pressure gas (air, nitrogen) or water flow, and zinc powder is obtained after cooling, classification, and drying. This process can accurately control the particle morphology, with a high yield of spherical zinc powder and a purity of more than 99.5%. It is currently the mainstream preparation method of spherical zinc powder. Through technological optimization, leading domestic companies have achieved large-scale release of 30,000 tons/year spherical zinc powder production capacity to meet the needs of anti-corrosion coatings, powder metallurgy and other fields.

2. Reduction method: Use zinc oxide or zinc slag as raw material, mix and heat with reducing agents such as coke and anthracite, reduce at high temperatures to generate metallic zinc vapor, and rapidly cool and desublimate to form zinc powder. Companies in Gansu and other places rely on zinc waste residue resources and adopt continuous multi-phase interface reaction technology to achieve efficient extraction of zinc resources at normal temperatures and pressures and promote high-value utilization of waste residue. The purity of the product can reach 98%-99%, which is suitable for chemical synthesis, feed additives and other scenarios.

3. Electrolysis method: Sponge zinc is obtained through electrolysis of zinc salt solution, and then zinc powder is obtained through crushing, grinding, and classification. The products of this process have high purity (up to 99.9%) and strong activity, but the production cost is high. It is mainly used in fields with strict purity requirements such as high-end batteries and electronic materials.

(2) High-end and refined preparation technology

In the field of laboratories and high-end production capacity, new processes focus on the preparation of zinc powder with special morphology and ultra-fine particle size. The vapor deposition method can prepare nanoscale zinc powder, which significantly increases the specific surface area, and greatly enhances the catalytic activity and conductivity; the mechanical ball milling method achieves particle refinement and morphology control through high-energy grinding, and can prepare flaky zinc powder to meet the needs of chromium-free Dacromet coating. Domestic enterprises have broken through the core technical barriers of flake zinc powder, and some new products have achieved import substitution and are used in high-end fields such as auto parts and military industry.

3. Diverse application areas: active empowerment of the entire industry chain

The global zinc powder market demand continues to rise, with my country as the main producer and consumer. The products cover many high-prosperity fields such as anti-corrosion, batteries, and chemicals. Spherical and flake zinc powder have formed a differentiated application pattern, and the industry scale has steadily expanded with downstream demand.

(1) Anti-corrosion coating field: core protective raw materials

About 40% of zinc powder is used in anti-corrosion coating production, especially zinc-rich coatings. Zinc powder forms sacrificial anode protection in the coating, which takes precedence over the oxidation reaction of the steel substrate. At the same time, the oxidation products fill the pores of the coating and enhance the shielding performance. It is widely used in outdoor facilities such as bridges, ships, and steel structures. Flake zinc powder performs well in chromium-free Dacromet coatings and forms a dense protective film through layered accumulation. It is suitable for scenarios such as automotive parts and military equipment that have high requirements for environmental protection and protection levels.

(2) Battery and energy storage fields: key electrode materials

Zinc powder is the core anode material of zinc-manganese batteries and zinc-air batteries. Its purity and particle size directly affect battery capacity and cycle life. With the development of the energy storage industry, the application of zinc powder in zinc-based energy storage batteries has gradually expanded. Highly active ultra-fine zinc powder can improve battery charge and discharge efficiency and stability. In 2024, my country's zinc powder market for zinc-manganese batteries will continue to grow, industry supply will increase significantly year-on-year, and East China will become the main consumer area.

(3) Chemical and metallurgical fields: efficient reducing agents

In chemical synthesis, zinc powder is used as an excellent reducing agent to prepare insurance powder, organic intermediates and other products. In the printing and dyeing industry, it can be used as an indigo dye reducing agent, silk printing color blocking agent, and in the oil and fat industry, it is used as a bleaching agent and purification and decolorizing agent. In the field of metallurgy, zinc powder can be used for precious metal extraction and alloy preparation. It can recover gold, silver and other elements in the ore through replacement reactions. It can also be used as an additive in powder metallurgy to improve the mechanical properties and wear resistance of alloy materials.

(4) Other featured applications

In the field of medicine, zinc powder can be used to prepare zinc paste, adhesive plaster and other external preparations, relying on its astringent and protective effects to assist in the treatment of skin inflammation; in the feed industry, it is used as a zinc source additive in livestock and poultry breeding to supplement trace elements needed for animal growth. In addition, zinc powder is also widely used in friction materials, phosphating treatment and other fields. Through surface modification technology, its application scenarios are still expanding.

4. Safety, environmental protection and industrial development trends

(1) Safe storage and environmental protection control

As a flammable, explosive and hazardous chemical, zinc powder requires safety management and control throughout the entire process of production, storage and transportation. Storage sites need to be equipped with explosion-proof electrical, lightning protection and anti-static devices, flammable gas alarm systems and emergency forced exhaust facilities. Human body electrostatic discharge devices are installed at the entrance. Metal shelves and equipment need to be reliably grounded and kept away from oxidants and acids to prevent reactions caused by moisture. Operations must be performed by certified special operations personnel, wearing protective clothing, protective masks and gloves to ensure good ventilation.

In terms of environmental protection, zinc powder production needs to strengthen the treatment of waste water and waste residue, the reduction process needs to control waste gas emissions, and the use of renewable raw materials such as zinc waste residue is encouraged to achieve resource recycling. Waste zinc-based products can recover zinc resources through fire and hydrometallurgy to promote the green transformation of the industry and reduce the risk of heavy metal pollution.

(2) Industry development trends

The zinc powder industry is evolving towards high-end, green and regional coordination. At the technical level, the research and development of high-end flake zinc powder has broken through foreign barriers, and the domestic substitution rate continues to increase. The demand for ultra-fine and high-purity zinc powder in the new energy and military fields has grown significantly. Enterprises' R&D investment focuses on morphology control and performance optimization, and multiple flake zinc powder and alloy powder projects are progressing steadily. In terms of production capacity layout, domestic enterprises optimize regional deployment capabilities, reduce logistics costs, and enhance product competitiveness through capacity synergy between the east, middle, and west regions.

At the market level, there is a significant price difference between ordinary zinc powder and high-end zinc powder, and high value-added products have become the core of corporate profits. In the future, with the development of new energy storage and high-end manufacturing industries, the demand for zinc powder will continue to grow. At the same time, driven by environmental protection policies, low-energy consumption processes and closed-loop recycling systems will be gradually improved to promote high-quality development of the industry.

From traditional anti-corrosion materials to high-end manufacturing core raw materials, zinc powder continues to empower the upgrading of various industrial chains with its controllable activity and morphological properties. Driven by the two-wheel drive of technological innovation and green development, this highly active metal powder will show broader application prospects in new energy, high-end equipment and other fields, helping industry iteration and efficient use of resources.