Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D5513-22 – Standard Test Method Technical Guide
📐 Scope and Materials Tested
This practice describes the multi-stage microwave digestion of industrial furnace feed streams and waste materials for trace element analysis. It has been successfully applied to samples of coal, coke, cement raw feed materials, and waste-derived fuels composed primarily of waste paint-related material. The practice is also effective for other waste materials such as fly ash, foundry sand, alum process residue, and cement kiln dust. Values are stated in SI units as standard.
⚙️ Digestion Procedure Details
The procedure involves weighing a sample and combining it with concentrated nitric acid in a PTFE-lined digestion vessel. The vessel is heated in a microwave unit following a programmed cycle. After venting, specified quantities of hydrofluoric and hydrochloric acids are added, and the mixture undergoes further heating. After another venting, a specified quantity of boric acid solution is added, and a final microwave heating is performed. The vessel is vented, and the contents are quantitatively transferred to a volumetric flask and brought to volume. Typically, only particulate carbon remains undissolved, which may require filtration or centrifugation.
| ⚡ Step | 🟦 Acid(s) Added | 📏 Description |
|---|---|---|
| 1 | Concentrated nitric acid | Initial microwave heating cycle |
| 2 | Hydrofluoric and hydrochloric acids | Secondary microwave heating for silicate dissolution |
| 3 | Boric acid solution | Final microwave heating for neutralization |
📊 Trace Elements and Regulatory Importance
This practice prepares samples for the determination of trace metals, including Ag, As, Ba, Be, Cd, Cr, Hg, Pb, Sb, and Tl. It supports compliance with 40 CFR 266 Subpart H, which governs hazardous waste burned in boilers and industrial furnaces and requires assessment of potential metals emissions from waste-derived fuels.
| 🟦 Element | 📐 Symbol | 📏 Regulatory Context |
|---|---|---|
| Antimony | Sb | Listed in 40 CFR 266 |
| Arsenic | As | Listed in 40 CFR 266 |
| Barium | Ba | Listed in 40 CFR 266 |
| Beryllium | Be | Listed in 40 CFR 266 |
| Cadmium | Cd | Listed in 40 CFR 266 |
| Chromium | Cr | Listed in 40 CFR 266 |
| Lead | Pb | Listed in 40 CFR 266 |
| Mercury | Hg | Listed in 40 CFR 266 |
| Silver | Ag | Listed in 40 CFR 266 |
| Thallium | Tl | Listed in 40 CFR 266 |
💡 Tip: Although validated for coal, coke, cement feed, and waste paints, this practice is effective for other waste types like fly ash and foundry sand. Verify sample compatibility and consider filtration for residual carbon.
⚡ Warning: This practice involves hazardous acids, including hydrofluoric acid. Consult Section 8 of the