5N grade high-purity lead ingots achieve mass production, accelerating domestic substitution in semiconductor packaging and photovoltaic energy storage fields

Recently, a joint research institution of leading domestic non-ferrous metal enterprises announced that 5N grade (purity ≥ 99.999%) high-purity lead ingots have been mass-produced on a large scale. The annual production capacity of a single production line has exceeded 5000 tons, and the total amount of key impurity elements is controlled within 5ppm. The core indicators have reached the international advanced level. This breakthrough has completely changed the pattern of China's long-term dependence on imported high-end high-purity lead, providing independent and controllable core raw material support for strategic emerging industries such as semiconductor packaging and photovoltaic energy storage, and significantly accelerating the process of domestic substitution in related fields.

1、 Breakthrough the bottleneck of purification through technological breakthroughs, mature and stable mass production processes

The core of mass production of 5N grade high-purity lead ingots lies in breaking through two major technical challenges: deep removal of trace impurities and pollution control during the production process. Previously, traditional domestic processes could only stably produce 4N grade (99.99% purity) lead ingots. To increase the purity to 5N grade, more than ten trace impurities such as bismuth, antimony, silver, copper, etc. need to be accurately removed, and some impurity contents need to be controlled at ppb level (one billionth), which is extremely difficult technically.

Domestic enterprises have established a complete purification system through a three-stage combined process of "pyrometallurgical refining+wet electrolysis+vacuum distillation". Firstly, the oxygen rich bottom blowing process is used to complete the preliminary purification of crude lead, removing most of the matrix impurities; Subsequently, by optimizing the electrolyte formula and accurately controlling the current density, the deep impurity removal in the electrolytic refining process was achieved, and the purity was increased to the 4N5 level; Finally, an innovative multi-stage vacuum distillation device was applied to further separate volatile impurities in a high temperature and high vacuum environment of 1100 ℃, resulting in a stable product purity of over 99.999%. At the same time, the production line is equipped with a 10000 level clean room and a fully enclosed inert gas protection system to avoid secondary pollution caused by dust and moisture in the air during the production process. The yield rate has increased to 82.1%, far exceeding the industry average.

The localization of key equipment also provides a guarantee for mass production. The fully automatic regional melting system independently developed by North Huachuang has achieved temperature field control at the 0.5 μ m level and has been stably applied in the production line; The domestic online ICP-MS detection system has a detection limit of 0.1 ppb and can monitor the content of 22 impurity elements in real time to ensure product quality consistency.

2、 Semiconductor packaging field: solving the bottleneck problem of high-end materials

In the field of semiconductor packaging, 5N grade high-purity lead ingots are the core raw materials for manufacturing packaging solder and sputtering targets. Their high purity and chemical stability directly determine the electrical performance and service life of chips. Semiconductor chip packaging requires reliable connection between the chip and external circuits through solder, while protecting the chip from external environmental corrosion. This requires that there be no excess impurities in the lead material that interfere with electronic signal transmission, and that the chip can withstand temperature fluctuations during operation.

Previously, over 90% of the 5N grade high-purity lead used in semiconductor packaging in China relied on imports from Germany, South Korea, and Australia. This not only resulted in high procurement costs but also posed a risk of supply chain instability. The domestically produced 5N grade high-purity lead ingots have passed the verification of top domestic semiconductor companies, and their key properties such as resistivity and thermal stability are on par with imported products, while the price has been reduced by about 20% -30%. At present, the product has been supplied in bulk to semiconductor packaging enterprises for the manufacture of high-end products such as compound semiconductors and infrared optoelectronic conversion devices. The substitution rate of domestic materials in related fields has rapidly increased from less than 15% to over 30%.

3、 Photovoltaic energy storage field: Empowering high-end battery performance upgrades

The demand for photovoltaic energy storage has exploded, becoming another major application scenario for 5N grade high-purity lead ingots. With the large-scale promotion of photovoltaic power plants and industrial and commercial energy storage projects, the requirements for raw material purity of lead carbon batteries and high-end valve regulated sealed lead-acid batteries continue to increase. 5N grade high-purity lead ingots can effectively reduce battery self discharge rate and improve cycle life, and their application proportion in large-scale energy storage power plants has reached 30%.

Data shows that lead carbon batteries manufactured using 5N grade high-purity lead ingots can increase their cycle life to over 3000 times, which is 20% longer than products using 4N grade lead ingots, and their charge and discharge efficiency is improved by 5% -8%. At present, domestically produced 5N grade high-purity lead ingots have entered the supply chain of companies such as CATL and BYD, and are used for the production of photovoltaic energy storage supporting batteries. With the expansion of application scale, it is expected that the demand for 5N grade high-purity lead ingots in the photovoltaic energy storage field will exceed 20000 tons by 2025, driving the substitution rate of domestic raw materials in this field to exceed 50%.

4、 The domestic substitution space is vast, and the industry pattern continues to optimize

China is the world's largest consumer of high-purity lead, with a market size of 5.86 billion yuan by 2024. The proportion of high-end products at 5N level and above has increased to 27.3%, and demand is still growing at an average annual rate of 18%. Previously, the dependence on imported 5N grade high-purity lead in China was over 60%. This mass production will accelerate the process of import substitution, and it is expected that the market share of domestically produced 5N grade high-purity lead ingots will increase to 41% by 2025, and is expected to exceed 75% by 2030.

At the policy level, 5N grade high-purity lead has been included in the "Guiding Catalogue for the First Batch of Key New Materials Application Demonstrations" and has received policy support such as additional deduction of research and development expenses and immediate refund of value-added tax. The industry concentration continues to increase, with leading enterprises such as Hunan Zhuye, Yunnan Chihong Zinc and Germanium, and Henan Yuguang Gold and Lead occupying over 80% of the country's high-purity lead production capacity through technological advantages, forming an industrial pattern of "stable production in the central region, capacity expansion in the western region, and refining in the eastern region". In the future, enterprises will further research and develop 6N level (99.9999%) ultra-high purity lead technology, expand its applications in cutting-edge fields such as quantum computing and superconducting materials, and continue to consolidate China's competitive advantage in the global high-purity lead market.