On January 26, the Ministry of Ecology and Environment disclosed that, in response to global mercury pollution prevention and control requirements, China will focus on core aspects such as the research and development of mercury-free catalysts to accelerate the comprehensive transition of the polyvinyl chloride (PVC) industry toward mercury-free production. This initiative is both a key measure to implement the amendments to the Minamata Convention on Mercury (hereinafter referred to as the "Convention") and an important practice demonstrating China's commitment to deepening global environmental governance and showcasing its role as a major country.

Recently, the Ministry of Ecology and Environment, in collaboration with relevant departments, issued the "Announcement on the Control Requirements for 12 Mercury-Added Products, Including Mercury-Containing Batteries, and the Production Process of Polyurethane Using Mercury-Containing Catalysts" (hereinafter referred to as the "Announcement"). The Announcement specifies strict production, import, and export controls for 12 categories of mercury-added products, including mercury-containing batteries, and completely prohibits the use of mercury-containing catalysts in polyurethane production.

In response to media inquiries, a relevant official from the Ministry's Department of Solid Waste and Chemicals noted that the issuance of the Announcement is an important supporting measure for China to address the upgraded control requirements of the Convention. It will provide clear policy guidance for mercury pollution prevention and control in key industries.

Mercury, as a heavy metal with high toxicity, bioaccumulation potential, and persistence, has become a core issue in global environmental governance. The Convention, adopted in 2013 and officially effective in 2017, has 153 parties as of the end of 2025, establishing a fundamental framework for global mercury pollution control. In November 2023, the fifth meeting of the Conference of the Parties to the Convention adopted amendments to further expand the scope of control for mercury-added products and mercury-using processes and tighten control requirements. Among these, the phase-out timeline for mercury-using processes in calcium carbide-based PVC production has become a central focus of recent international negotiations.

As the world's largest producer and user of calcium carbide-based PVC, China's mercury usage in this industry once accounted for approximately 60% of the country's total mercury consumption. Consequently, the progress of its transition to mercury-free production has attracted significant international attention.

It is reported that in the production of calcium carbide-based PVC, traditional processes use mercuric chloride as a catalyst. During the reaction, mercury is prone to sublimation and loss, generating pollutants such as mercury-containing waste catalysts, waste acid, and wastewater. This not only harms the ecological environment and human health but also faces long-term challenges due to the scarcity of mercury resources.

In recent years, China has steadily advanced mercury pollution prevention and control, successfully achieving the compliance target of "halving mercury usage per unit of product by 2020 compared to 2010." Low-mercury catalysts have fully replaced high-mercury catalysts, and technologies such as deep hydrochloric acid desorption and efficient gas-phase mercury recovery have seen significantly increased adoption rates.

Despite these phased achievements, the industry's transition still faces critical bottlenecks. The aforementioned official emphasized that current mercury-free catalysts have yet to achieve breakthroughs in technological maturity and economic feasibility, which remains the core obstacle preventing the PVC industry from completely eliminating its reliance on mercury.

A recent research report from Kaiyuan Securities indicates that current mercury-free alternatives mainly include two approaches: gold-based catalyst modifications and ethylene-based process upgrades. However, both face cost pressures—the gold-based catalyst route may increase costs by approximately 100 yuan per ton, while the ethylene-based process requires about 80% higher investment per ton compared to the calcium carbide-based method. This makes the transition particularly challenging for small and medium-sized enterprises.

In response to this situation, the Ministry of Ecology and Environment has outlined the next steps: strengthening cross-departmental coordination and collaboration, increasing policy support and technological innovation guidance for the research and development of mercury-free catalysts, promoting deeper integration of industry, academia, and research, and accelerating breakthroughs in technological and cost barriers. At the same time, efforts will continue to strengthen environmental supervision in the industry, improve the whole-process management system for mercury-containing waste, and promote the centralized and large-scale development of waste mercury catalyst recycling and disposal to reinforce mercury pollution prevention and control measures.

Industry analysis suggests that with the implementation of the Convention amendments and the strengthening of domestic policies, the PVC industry will undergo structural adjustments. Smaller-scale enterprises with weaker profitability may accelerate their exit from the market, leading to continuous optimization of the industry's supply structure. The technological breakthrough of mercury-free catalysts will not only fundamentally address the mercury pollution issue in calcium carbide-based PVC production but also inject new momentum into the green transformation of China's chlor-alkali industry, contributing to the dual goals of achieving carbon peaking and carbon neutrality and continuously improving ecological and environmental quality.