Recycled Metal Composition Analysis Services: Elemental Testing for Secondary Metals

Recycled metal composition analysis services provide accurate elemental determination for scrap aluminum, copper, ferrous alloys, and other secondary metals, enabling fair valuation, reliable alloy sorting, and precise furnace charge control. Accredited third-party laboratories apply spark OES, ICP-OES, XRF, and combustion analytical techniques in accordance with ISO, ASTM, EN, and GB standards, supporting recyclers, traders, smelters, and manufacturers throughout the secondary metals supply chain.

Technical Overview

Recycled metals have become a fundamental feedstock for the global metals industry, offering significant energy savings and carbon-footprint reduction compared with primary production. However, secondary materials are inherently heterogeneous: incoming scrap streams may contain mixed alloys, coated or painted surfaces, attached steel components, oils, rubber, plastics, and accumulated tramp elements. The exact chemical composition of a recycled metal lot determines its market grade, its price, and whether it can be remelted directly or requires blending, refining, or downgrading.

Composition determination services for recycled metals address these challenges by combining representative sampling protocols with multi-element instrumental analysis. Typical capabilities of accredited third-party laboratories include:

• Full quantitative analysis of major alloying elements, minor elements, and trace impurities in a single workflow
• Alloy identification and grade verification against recognized designation systems (1xxx–7xxx aluminum series, 300/400 series stainless steels, brass and bronze families)
• Determination of tramp and deleterious elements such as lead, bismuth, tin, antimony, and arsenic that accumulate across recycling loops
• Restricted-substance screening to support regulatory compliance, including RoHS-type requirements for low levels of Pb, Cd, Hg, and Cr(VI)
• Reporting aligned with ISO/IEC 17025 laboratory competence requirements for use in trade settlement and dispute resolution

Testing Samples

Aluminum Scrap

Common sample types include used beverage cans (UBC), mixed old sheet and clippings, castings, pistons, lithographic plates, extrusion scrap, wires and cables, aluminum dross, and shredded mixed-metal concentrates. Aluminum recycling is particularly sensitive to iron and silicon contamination, as well as magnesium and zinc variation, so accurate composition data is essential before remelting.

Copper and Copper Alloy Scrap

Samples cover bare bright wire, No. 1 and No. 2 copper grades, copper clad steel, mixed brass such as honey and honeyberry, phosphor bronze, gunmetal, and copper-bearing sludge or ash. For copper refiners, trace levels of lead, tin, bismuth, and antimony strongly influence electrolytic refining performance and final cathode quality.

Ferrous and Stainless Steel Scrap

Ferrous samples include heavy melting steel, shredded steel, cast iron, boron-added steel turnings, and austenitic or ferritic stainless steels in the 300 and 400 series. Key measurements include carbon, sulfur, phosphorus, manganese, chromium, nickel, molybdenum, and copper, together with residual elements that affect weldability and ductility.

Zinc, Lead, and Other Nonferrous Scrap

Die-cast zinc alloys, zinc dross and skimmings, lead-acid battery grids and paste, solder, nickel-based superalloy scrap, and titanium turnings are analyzed for major and minor elements to establish recovery value and refining strategy.

Slags, Drosses, and Residues

Smelter slags, melting furnace dross, baghouse dust, and grinding swarf are tested to quantify recoverable metal content, guiding whether the material is a product, a recyclable intermediate, or a waste requiring controlled handling.

Electronic and Complex Scrap

Printed circuit boards, CPU and memory modules, connector pins, and shredded mixed electronic waste (for example, Zorba-type concentrates) are analyzed for copper, aluminum, precious metals such as gold, silver, palladium, and platinum, and for hazardous elements relevant to transboundary waste regulations.

Testing Items

Testing programs are tailored to the material class and commercial purpose. Representative elemental suites include:

• Light metals: Al, Mg, Si, Fe, Cu, Zn, Mn, Ti, Cr, Ni, V in aluminum and magnesium scrap
• Heavy nonferrous metals: Cu, Zn, Sn, Pb, Ni, Fe, Al, Mn, P, Sb, As, Bi, Cd in copper alloys and brasses
• Ferrous metals: C, S, P, Si, Mn, Cr, Ni, Mo, Cu, Sn, V, Ti, Nb, W in steel, cast iron, and stainless scrap
• Interstitial gases: O, N, H in steel and titanium scrap where embrittlement risk must be assessed
• Precious metals: Au, Ag, Pd, Pt in electronic scrap, sweeps, and refining intermediates
• Hazardous and restricted substances: Pb, Cd, Hg, As, Cr(VI), brominated compounds relevant to environmental compliance

Testing Methods

Spark Optical Emission Spectrometry (Spark OES)

Spark OES is the workhorse for solid metallic samples, delivering simultaneous multi-element results within minutes. Standardized methods include ASTM E415 for carbon and low-alloy steels, ASTM E1251 for aluminum and aluminum alloys, ASTM E1086 for stainless steels, and corresponding GB/T 223, GB/T 7999, and GB/T 11170 procedures. Samples are milled or turned to obtain a flat, clean surface before sparking.

Inductively Coupled Plasma Spectrometry (ICP-OES and ICP-MS)

For chips, turnings, dross, slags, dusts, and small or irregular samples, acid digestion followed by ICP-OES provides broad elemental coverage with detection limits down to the ppm level, following practices such as ASTM E1479 and classical schemes like ASTM E34 for aluminum and ASTM E478 for copper alloys. ICP-MS extends capability to ultra-trace impurities and precious metal assay.

X-Ray Fluorescence Spectrometry (XRF)

Wavelength-dispersive and energy-dispersive XRF, covered by the terminology and practices of ASTM E1621, enable rapid, largely non-destructive screening of solids, powders, and pressed pellets. Handheld and benchtop XRF are widely used for incoming-scrap sorting and pre-screening before full laboratory confirmation.

Combustion and Inert Gas Fusion Analysis

High-temperature combustion infrared absorption and inert gas fusion, standardized in ASTM E1019, are applied to determine carbon, sulfur, nitrogen, oxygen, and hydrogen in ferrous and specialty alloys, where these interstitial elements critically affect melt quality and mechanical properties.

Classical Wet Chemistry

Gravimetric, titrimetric, and electrolytic methods remain reference procedures for high-precision determinations such as electrolytic copper content and alloy arbitration, and they serve to validate instrumental calibrations.

Sampling and Sample Preparation

Because scrap is heterogeneous, services typically include incremental sampling and sample reduction plans, driling or milling of drillings, cleaning to remove coatings, oils, and attached non-metallics, and, where required, remelting of a representative portion into a homogeneous button before instrumental analysis. Melt-loss and visual contamination assessment may accompany the chemical report.

Applications

• Scrap trading and price settlement: independent certificates of analysis define metal content and impurity levels used in contract pricing formulas
• Import and export inspection: composition reports support customs classification and compliance declarations for cross-border scrap shipments
• Furnace charge calculation: smelters use certified multi-element data to blend secondary feedstock and keep tramp elements within specification limits
• Alloy sorting and identification: rapid spectroscopic verification prevents accidental mixing of incompatible alloy families during processing
• Quality control of secondary ingots and billets: producers of recycled alloys verify conformity to customer and standard specifications before delivery
• Recovery and refining decisions: analysis of drosses, slags, and e-waste determines recoverable metal value and downstream processing routes
• Environmental and regulatory compliance: testing confirms restricted substance levels and supports waste-versus-product determinations

FAQ

How much sample is required for analysis?

For spark OES, a solid piece of at least 15–20 mm across with a flat analyzable surface is ideal; alternatively, 30–100 g of clean drillings or turnings is sufficient for ICP digestion. Highly heterogeneous lots may require several kilograms so that representative subsamples can be prepared.

What is the typical turnaround time?

Routine spark OES and XRF results are often available within one to three working days after sample receipt. ICP and precious-metal programs, and remelting workflows, generally require three to seven working days depending on sample complexity.

How is heterogeneity in scrap handled?

Laboratories apply incremental sampling schemes, combine and reduce the sample, and where necessary remelt a representative portion to homogenize the material before analysis. Multiple replicate determinations and melt-loss measurement improve the reliability of the reported composition.

Which standards govern the testing?

Methods are performed according to ASTM, ISO, EN, JIS, and GB/T standards as appropriate to the alloy system, for example ASTM E1251 and GB/T 7999 for aluminum, ASTM E415 and GB/T 223 for steel, and ASTM E1019 for carbon, sulfur, nitrogen, and oxygen. Testing is typically carried out under an ISO/IEC 17025 accredited quality system.

Can painted, coated, or oily scrap be analyzed?

Yes. Surfaces are mechanically or chemically cleaned, and coatings are removed or analyzed separately so that the reported composition reflects the metallic value of the material. Melt-loss testing quantifies the proportion of non-metallic and volatile contamination in the lot.

Is composition testing sufficient to establish the scrap grade?

Chemical composition is a central factor in grade determination, but full grading may also consider physical form, cleanliness, and yield. Laboratories therefore combine composition certificates with melt-loss and contamination assessment to support a complete grade evaluation.