Rhodium
(information)
✅ Continuing with **Rhodium (Rh)** — another **platinum-group metal (PGM)** with exceptionally high value, primarily due to its **role in catalytic converters**. It’s also used in **optics, coatings, and precision electronics** thanks to its **reflectivity, corrosion resistance, and thermal stability**. --- # 🚗 Modern Rhodium Uses by Industry (Option A Format) ### 🔥 **1–4: Automotive Emissions Control (~75–80%)** 1. **Three-Way Catalytic Converters (Gasoline Engines)** – Core use: converts NOx to nitrogen. 2. **Diesel Emission Reduction Systems** – Selective catalytic reduction support. 3. **Motorcycle & Small Engine Catalysts** – Compliance for global emissions standards. 4. **Hydrogen Fuel Reforming Catalysts (Emerging)** – Rhodium-platinum systems for hydrogen purification. --- ### ⚙️ **5–8: Industrial & Chemical Catalysis (~10–12%)** 5. **Nitric Acid Production Catalysts** – Oxidation of ammonia in large-scale synthesis. 6. **Hydrosilylation Catalysts** – Silicone polymer production. 7. **Fine Chemical & Pharmaceutical Synthesis** – Rh-based hydrogenation and coupling chemistry. 8. **Petrochemical Cracking & Reforming Catalysts** – High-temperature catalyst beds. --- ### 💡 **9–12: Electronics, Optics & Sensors (~4–6%)** 9. **Thermocouples (Rh-Pt Alloys)** – Type B, R, and S thermocouples for high-temp measurement. 10. **Infrared & Optical Mirrors** – Highly reflective rhodium coatings. 11. **Electrical Contacts & Relay Points** – Wear-resistant contact surfaces. 12. **Hall Effect & Gas Sensors (Experimental)** – Thin-film rhodium circuits. --- ### 🛡️ **13–16: Decorative & Protective Coatings (~2–4%)** 13. **Jewelry Plating (White Rhodium Finish)** – Luxury watch and ring coatings. 14. **Silverware & Instrument Protection** – Anti-tarnish plating. 15. **Reflective Coatings for High-End Optics** – Laser mirrors and telescopes. 16. **Consumer Electronics Accents (Premium Finishes)** – Limited-use branding accents. --- ### 🧪 **17–20: Research & Advanced Technologies (~1–2%)** 17. **Nuclear Reactor Control Rods (Experimental Alloys)** 18. **Electrochemical Oxygen Sensors** – High-temp detection elements. 19. **Plasma & Arc Research Electrodes** – Stable under ion bombardment. 20. **Spacecraft Surface Coatings (Theoretical)** – Extreme corrosion protection. --- ### 📌 Sector Share Summary | Sector Group | % of Global Rhodium Use | | -------------------------------- | ----------------------- | | Automotive Emission Catalysts | ~75–80% | | Industrial & Chemical Catalysis | ~10–12% | | Electronics & Optical Components | ~4–6% | | Decorative & Protective Coatings | ~2–4% | | Research & Advanced Technologies | ~1–2% | --- ✅ **Next in the Platinum Group lineup is:** **Palladium (Pd)** — another major emissions catalyst metal, but with **huge roles in hydrogen storage, electronics, and jewelry**. Say **“continue”** and I’ll move on to **Palladium** with the same industry breakdown.Known Methods of Extraction
Perfect 👍 — next in **periodic table order** is **Rhodium (Rh, atomic number 45).** Rhodium is a **rare transition metal** that is **extremely scarce** and does **not occur free** in nature. It is primarily obtained as a **byproduct of platinum and nickel refining**, usually from **platinum group metal (PGM) ores**. Extraction involves **dissolution, selective precipitation, and reduction**. Here are the **20 most common methods of extracting Rhodium**: --- # **20 Most Common Methods of Extracting Rhodium** ### **A. Extraction from Platinum-Group Ores** 1. **Dissolution of PGM Concentrates in Aqua Regia** – Dissolves Rh and other PGMs. 2. **Selective Precipitation as Rhodium Chloride Complexes** – Separates Rh from Pt and Pd. 3. **Oxidative Conversion to Rhodium Salts (RhCl₃·xH₂O)** – Intermediate purification step. 4. **Ion Exchange Chromatography** – Purifies Rh from mixed PGM solutions. 5. **Solvent Extraction of Rhodium Complexes** – Uses organophosphorus or amine extractants. 6. **Fractional Crystallization of Rhodium Compounds** – Separates Rh from Ir, Pd, and Pt. --- ### **B. Reduction to Metallic Rhodium** 7. **Hydrogen Reduction of Rhodium Chloride or Oxide → Rh Metal** – Laboratory or small-scale industrial method. 8. **Electrolytic Deposition of Rhodium from Aqueous Solutions** – High-purity metallic Rh production. 9. **Aluminothermic Reduction of Rhodium Salts** – Lab-scale method. 10. **Magnesiothermic Reduction of Rhodium Oxide** – Experimental reduction method. 11. **Thermal Decomposition of Rhodium Compounds** – Produces metallic Rh. 12. **Carbon Reduction of Rhodium Oxides** – Specialty method for lab-scale production. --- ### **C. Recovery from Byproducts / Secondary Sources** 13. **Recovery from Platinum Refinery Residues / Slags** – Acid leaching + selective precipitation. 14. **Recovery from Nickel-Copper Sulfide Ore Refining Byproducts** – Trace Rh extracted. 15. **Recovery from Spent Catalysts (Automotive or Industrial)** – Chemical dissolution + Rh precipitation. 16. **Recovery from Recycled Jewelry or Alloys Containing Rh** – Hydrometallurgical methods. --- ### **D. Laboratory / Experimental Methods** 17. **Plasma Reduction of Rhodium Salts or Oxides** – High-purity experimental method. 18. **Solar-Thermal Reduction of Rhodium Oxide or Chloride** – Renewable-energy experimental method. 19. **Zone Refining of Metallic Rhodium** – Produces ultra-high purity Rh. 20. **Chemical Vapor Deposition (CVD) of Rhodium** – Produces thin films for electronics and catalysis. --- ✅ **Summary:** * **Main industrial sources:** Platinum-group metal ores and refining residues. * **Primary extraction steps:** Dissolution → selective precipitation → complex formation → reduction → metallic Rh. * **Metallic rhodium:** Produced via hydrogen reduction, electrolysis, or metallothermic methods. * **Byproduct sources:** Nickel-copper ores, platinum refining residues, spent catalysts, recycled alloys. * **Laboratory/experimental:** Plasma reduction, solar-thermal, zone refining, CVD for electronics/catalysis. --- Next in periodic order is \*\*Palladium (Pd, atomic number 46). Do you want me to continue with **20 extraction methods for Palladium**?
