Mineral processing
Separating valuable minerals from ore through beneficiation processes.
Marathon · CC BY-SA 2.0
Mineral processing, a branch of extractive metallurgy, involves separating valuable minerals from their ores. Depending on the methods used, it may also be called ore dressing or ore milling. Beneficiation refers to any process that enhances the economic value of ore by removing gangue minerals, yielding a higher-grade product known as ore concentrate and a waste stream called tailings. Recovery, the mass or molar fraction of the valuable mineral or metal extracted from the ore and transferred to the concentrate, is a key concept. Rare-earth minerals, often found in mineral sands, are typically processed in a mineral separation plant.
Historically, before heavy machinery, raw ore was broken by hand with hammers in a process called spalling. Mechanical means later emerged; stamp mills were used near Samarkand in Central Asia as early as 973, with evidence of their use in early medieval Persia. By the 11th century, stamp mills were widespread across the medieval Islamic world, from Spain and North Africa to Central Asia. Later, Cornish stamps used iron hammers mounted in a vertical frame, raised by cams on a waterwheel shaft and falling onto ore by gravity. Iron beneficiation dates to at least 800 BC in China with the bloomery, an early smelting method that produced fires hot enough to melt oxides into a liquid separating from iron. The bloomery was phased out by the blast furnace but remained in use in Africa and Europe into the early second millennium. The blast furnace produced pig iron; the first European blast furnaces appeared in the early 1200s in Sweden and Belgium, and in England in the late 1400s. Pig iron is hard and brittle due to high carbon content. In 1856, the Bessemer process converted brittle pig iron into more malleable steel. Since then, technologies like the electric arc furnace, basic oxygen steelmaking, and direct reduced iron (DRI) have replaced it. For sulfide ores, beneficiation requires sulfur removal before smelting. Roasting, the primary method, involved placing wood on ore heaps and setting them on fire to aid oxidation, as in the reaction 2 Cu2S + 3 O2 → 2 Cu2O + 2 SO2. Early roasting was done outdoors, releasing large sulfur dioxide clouds that harmed ecosystems, as seen in Sudbury, Ontario, and the Inco Superstack, compounded by deforestation for wood fuel. The simplest separation method is picking out individual crystals, tedious for small particles. Another method relies on density differences: heavier metallic minerals drop out of suspension faster, while lighter ones are carried further by water. Panning and sifting for gold use both methods. Devices called bundles exploited this property, followed by advanced machines like the Frue vanner, invented in 1874. Other historical equipment includes the hutch, a trough used with ore-dressing machines, and the keeve or kieve, a large tub for differential settlement.
Beneficiation can begin inside the mine. Most mines have a crusher where ore and gangue are separated, making transport easier. After crushing, ore goes through a grinder or mill to produce fine particles. Dense media separation (DMS) stratifies crushed aggregate by density, aiding separation. Performing DMS before grinding reduces waste rock volume, lowering equipment wear and operating costs. After milling, physical separation uses ore properties like gravity, flotation, or magnetic separation. Sizing ore particles with industrial screens or classifiers is important beforehand. Gravity separation uses centrifugal forces and specific gravity; magnetic separation removes magnetic gangue or extracts magnetic target ore; DMS is also a physical method. When physical properties are insufficient, chemical processes like froth flotation, leaching, and electrowinning are used. Froth flotation relies on hydrophobicity to separate minerals.
- field
- Extractive metallurgy
- known_for
- Separating valuable minerals from ores via beneficiation processes
- key_concept
- Recovery: mass fraction of valuable mineral extracted to concentrate
- early_method
- Spalling (hand-hammering ore)
Lore & Background
Before the advent of heavy machinery, raw ore was broken up by hand using hammers, a process called spalling. Mechanical means eventually replaced this, with stamp mills in use near Samarkand as early as 973, and later in Persia during the early medieval period. By the 11th century, stamp mills were widespread across the medieval Islamic world. A later example was the Cornish stamps, which consisted of iron hammers mounted in a vertical frame, raised by cams on a waterwheel shaft and falling onto the ore by gravity. Iron beneficiation dates to at least 800 BC in China with the bloomery, an early form of smelting that produced fires hot enough to melt oxides into a liquid separating from the iron. The bloomery was later replaced by the blast furnace, which produced pig iron; the first European blast furnaces appeared in the early 1200s around Sweden and Belgium, and in England by the late 1400s. The Bessemer process of 1856 turned brittle pig iron into steel, and subsequent technologies like the electric arc furnace, basic oxygen steelmaking, and direct reduced iron followed. For sulfide ores, roasting was used to remove sulfur before smelting, often done by placing wood on ore heaps and setting it alight, releasing sulfur dioxide that caused severe environmental harm. The simplest separation method involved picking out individual crystals, while another method relied on density differences, with heavier metallic minerals settling faster in water. Devices like the Frue vanner, invented in 1874, and earlier tools such as the hutch and keeve were used for differential settlement.
Reader's Guide
Mineral processing is fundamental to extractive metallurgy, enabling the economic recovery of valuable minerals from ores. Its history spans from ancient hand-spalling and stamp mills to modern crushing, grinding, and chemical separation. Key unit operations include comminution (size reduction), sizing (particle separation), concentration (using physical or chemical properties), and dewatering. Processes like dense media separation, froth flotation, and leaching allow efficient extraction. The concept of recovery—the fraction of valuable mineral carried to concentrate—is central. Environmental impacts, such as sulfur dioxide from roasting (e.g., at Sudbury, Ontario), highlight the need for improved methods. Mineral processing remains essential for producing metals and minerals used in modern industry.
Did You Know?
- Iron beneficiation using a bloomery dates to at least 800 BC in China.
- Roasting of sulfide ores produced sulfur dioxide clouds that harmed ecosystems, as seen in Sudbury, Ontario.
Mission, Scope, and Global Community
The Minerals, Metals & Materials Society stands as a professional body dedicated to the full spectrum of materials science and engineering, spanning from the earliest stages of mineral extraction and primary metals production all the way through to cutting-edge applications of advanced materials. Based in Pittsburgh, the United States, the organization nonetheless operates on a truly global scale, drawing roughly thirteen thousand professional and student members from over seventy countries across six continents. Its membership roster includes metallurgical engineers, materials scientists, researchers, educators, and administrators who collectively shape the direction of the field. Beyond simply gathering specialists, the society actively fosters the exchange of technical knowledge, pushes technology transfer across borders, and invests in the education and professional development of both seasoned practitioners and emerging students. It also plays a role in accrediting educational programs and supporting the registration of professional engineers, a function rooted in the U.S. context. Ethical conduct, environmental stewardship, and a sense of worldwide professional unity are woven into the organization's core identity, all sustained by a volunteer-driven governance model in which members participate at every level of policy, programming, and publication decisions.
Five Technical Divisions
The society organizes its technical work through five distinct divisions, each responsible for programming conferences, developing content for publications, and carrying out specialized activities within its domain. The Extraction & Processing Division focuses on the front end of the materials pipeline, dealing with how raw minerals are recovered and refined. The Functional Materials Division addresses materials engineered for specific performance characteristics. The Light Metals Division concentrates on aluminum, magnesium, and related non-ferrous alloys. The Materials Processing & Manufacturing Division covers the transformation of raw materials into usable products, while the Structural Materials Division deals with the metals and alloys that form the backbone of infrastructure, transportation, and construction. Together, these divisions ensure that the society's conferences, journal content, and professional development programs reflect the breadth of the field rather than narrowing it to a single sub-discipline. This divisional structure also allows members to engage deeply with their specific area of expertise while still benefiting from cross-disciplinary exposure at society-wide events. The divisions serve as the operational engine behind the society's programming, translating broad organizational goals into focused, technically rigorous activities that practitioners can apply directly in their work.
Journals and Technical Publications
As a major publisher within the materials community, the society produces seven internationally respected technical journals that collectively cover the full breadth of minerals, metals, and materials science. JOM, published monthly, explores the complete range of the discipline. The Journal of Electronic Materials delivers peer-reviewed articles each month focused specifically on advances in electronics materials. Metallurgical and Materials Transactions operates as two archival journals: Volume A, appearing monthly, addresses physical metallurgy and materials science, while Volume B, published bi-monthly, covers process metallurgy and materials processing science. The Journal of Sustainable Metallurgy, a quarterly publication, examines metallurgical processes and innovations aimed at making metal-producing industries more environmentally responsible. Integrating Materials and Manufacturing Innovation explores how computational approaches support Integrated Computational Materials Engineering. Beyond these journals, the society releases numerous proceedings volumes each year containing papers presented at its sponsored meetings, ensuring that the latest research findings reach the broader professional community through both peer-reviewed and conference-based channels.
Roadmapping Studies and Practical Guidance
In addition to its journals, the society has developed a series of influential technology and roadmapping studies that convene leading experts to produce practical guidance for the minerals, metals, and materials communities. These publications are made freely accessible to the public, broadening their impact well beyond the membership base. Topics span a wide range of strategic challenges: one study maps the highest-impact research areas for stationary electrical energy storage, while a three-part investigation explores how new materials and processing breakthroughs can reduce carbon emissions and improve energy security. Another compiles the expertise of nearly fifty technical leaders to offer a practical three-year plan for implementing Integrated Computational Materials Engineering in aerospace, automotive, and maritime industries. Additional studies address diversity and inclusion in the profession, modeling across length and time scales, building a materials data infrastructure, next-generation manufacturing technologies, verification and validation of computational models, and a disruptive concept called metamorphic manufacturing that blends traditional metalsmithing with intelligent robotic systems. Together, these reports serve as actionable blueprints for advancing the field.
Gallery
More in Manufacturing And Materials 1-24
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record