The furnace fire is blazing, reflecting the concentrated faces of the workers. A piece of heavy
lead concentrate is thrown into the furnace, and the hot molten metal rushes and flows in the
channel, eventually solidifying into silver-gray lead ingots. In the central control room of the
modernized plant, engineers keep a close eye on the real-time data on the screen: "Temperature,
pressure, emission concentration, everything is in the optimal zone. Nowadays, the technology
not only pursues the output, but also the environmental responsibility behind each gram of lead.
" From an ancient civilization to a cutting-edge industry, lead production is undergoing a quiet
but profound transformation.
The source of lead: two parallel lifelines
Modern lead production follows two critical paths:
Primary lead: the journey from ore to metal
Mining and beneficiation: Lead and zinc ores often go hand in hand. The ore is crushed and ground
fine, and then flotation separates the lead concentrate containing more than 60% lead.
Pyrometallurgical Smelting (Mainstream):
Sintering and Roasting: Concentrates are sintered with a mixture of melts to desulphurize and form a
hard, porous sintered mass.
Blast furnace smelting: Sintered lumps, coke and flux are added to a blast furnace. The coke is burned
to provide heat and produce reducing gases (CO), which reduce the lead oxide to crude lead. Impurities
are separated by forming slag. The SO₂-containing flue gas is efficiently collected for acid production.
Crude lead refining:
Fire refining: melting, adding sulfur to remove copper, adding alkali refining to remove arsenic, antimony
and tin, and adding zinc to extract silver (forming silver and zinc shells), etc., gradually removing impurities.
Electrolytic refining: The lead after fire refining is cast into anode, pure lead sheet as cathode, and
electrolyzed in fluorosilicic acid electrolyte to get the refined lead with purity up to 99.99% or above.
Recycled Lead: A Core Pillar of the Circular Economy
Source: Waste lead-acid batteries (accounting for the absolute majority), cable sheaths, lead plates,
lead alloys, etc.
Pre-processing: Waste batteries are crushed and sorted (separating plastics, lead paste, separators, etc.).
Smelting:
Short kiln/rotary kiln smelting: Processing lead paste (mainly composed of PbSO₄, PbO₂, etc.), and
outputting crude lead under reducing atmosphere.
Reflector/electric furnace melting: Processing lead alloy parts such as grates.
Advanced technologies: Wet metallurgical technologies (e.g., solid-phase electrolysis, leach-electrolysis)
are also being developed with the aim of recovering lead in a more environmentally friendly and low-energy way.
Refining: Similar to primary lead, the refining process results in refined lead or lead alloys that meet standards.
Recycled Lead: The Unshakeable Green Lead Player
Recycled lead already dominates the global supply of lead (well over 50%, and in some regions as much as 70-80%)
and its strategic value is irreplaceable:
Resource saving: greatly reduces dependence on virgin minerals and protects natural resources.
Energy Consumption Advantage: The energy consumption of production is only 25%-40% of that of virgin lead,
which significantly reduces carbon emissions.
Reduced environmental burden: Effectively solve the environmental risks of lead-containing waste such as used
lead-acid batteries, turning waste into treasure.
Cost-effective: Recycling costs are typically lower than mining and smelting costs for virgin minerals.
Core Challenges and Green Breakthroughs in Lead Production
Lead production, especially traditional smelting, has faced serious environmental and energy challenges. The
modern industry is making a green transition through continuous innovation:
Exhaust gas treatment: SO₂ recycling acid production technology is maturely applied, and tail gas desulfurization
ensures compliance with emission standards. High-efficiency dust collection system (electric dust removal, bag
dust removal) strictly controls the escape of lead dust and particulate matter.
Wastewater recycling and treatment: Maximize the recycling of production wastewater. Deep treatment of end
wastewater to ensure that heavy metals (lead, cadmium, etc.) and other pollutants are discharged according to standards.
Solid Waste Resourcing:
Smelting slag is treated as building material or landfill material.
Anode sludge from electrolytic refining is an important raw material for extracting valuable metals such as gold,
silver and bismuth.
Plastics separated from recycled lead (e.g. battery case PP) are also effectively recycled.
Process upgrading:
Oxygen-enriched smelting/direct lead refining technology: such as the Kiefsite method, QSL method, etc., with
shorter process, lower energy consumption and better environmental protection (although it has not completely
replaced the blast furnace, but it represents the direction).
Exploration of hydrometallurgy: providing cleaner options for recycled lead and complex material handling.
Automation and Intelligence: DCS control system is widely used in large-scale smelters to optimize production
parameters and environmental protection indexes through real-time monitoring and optimization, thus improving
efficiency and safety.
Lead: an indispensable cornerstone of modern industry
Despite the challenges, there is no substitute for the fundamental role of refined lead in modern society:
Lead-acid batteries: the core energy storage unit for car starting, electric bicycles, uninterruptible power supplies (UPS),
and new energy storage (e.g., photovoltaic, wind power), accounting for more than 80% of global lead consumption.
Radiation protection: X-ray room, nuclear medicine, nuclear industry, the key shielding materials.
Chemical corrosion-resistant materials: acid industry, chemical anticorrosion field of lead lining equipment, pipes, components.
Alloy and solder: with tin, antimony and other solder, bearing alloy, printing alloy.
Other areas: cable sheathing (although replaced, still have applications), ammunition, counterweights, etc.
The way forward: cleaner, more efficient, more circular
The future of the lead industry is clear:
Continued consolidation of the dominant position of recycled lead: Improvement of the recycling network,
upgrading of the recycling rate and the efficiency and environmental friendliness of recycling technologies
(especially the wet process).
Green upgrading of primary lead technology: Promote cleaner and more efficient smelting technology, and
continuously reduce energy consumption and emission intensity.
Total Life Cycle Management: Establishing a closed-loop management system for lead, from mine to product to
recycling, to minimize the environmental footprint.
Material Science Exploration: Researching the potential application of lead in new types of batteries, such as
lead-carbon batteries, while ensuring safety.
In the control room, engineers record the data of the shift, and the jumping curves on the screen tell the story of
the precision and responsibility of the modern lead industry. Outside the window, stacks of shiny silver recycled
lead ingots are neatly stacked, about to go on a new mission. From the ancient furnace to the intelligent production
line, the production of lead has never stopped evolving. Under the wave of green manufacturing and circular
economy, the lead industry is breaking the waves with technology as oar and responsibility as rudder. It not only
provides the cornerstone material to support modern civilization, but also inscribes the sustainable answer of the
metal in the grand proposition of resource recycling and environmental protection. Every refining and purification
is not only the sublimation of metal, but also the crystallization of the wisdom of industry and ecological symbiosis.