Selenium
(information)
Here’s a structured breakdown of the **20 most common uses of Selenium**, grouped by sector with approximate global consumption shares: --- # 📊 Global Selenium Uses by Sector --- ### **1–5: Glass & Ceramics (~35–40%)** 1. **Glass De-colorizer** – Neutralizes green tint from iron impurities. 2. **Glass Coloring** – Produces red, bronze, and pink tints. 3. **Optical Glass & Lenses** – Specialized applications. 4. **Ceramics & Enamels** – Adds color and opacity. 5. **Architectural Glass** – Solar control coatings. --- ### **6–10: Metallurgy & Alloys (~25–30%)** 6. **Steel Additives** – Improves machinability. 7. **Copper Alloys** – Increases strength and corrosion resistance. 8. **Lead Alloys (Batteries, Cable Sheathing)** – Enhances durability. 9. **Bearing Metals** – Adds wear resistance. 10. **Deoxidizer in Metallurgy** – Removes oxygen from molten metals. --- ### **11–15: Electronics & Energy (~15–20%)** 11. **Photovoltaic Cells (CdSe, CIGS)** – Thin-film solar panels. 12. **Rectifiers & Photoreceptors** – Early use in electronics, niche today. 13. **Xerography (Photocopiers)** – Selenium drum technology (historical, declining). 14. **Semiconductors & Photodetectors** – Light-sensitive applications. 15. **Battery & Energy Storage Research** – Next-gen Li–Se and Na–Se batteries. --- ### **16–20: Chemicals, Agriculture & Health (~10–15%)** 16. **Pigments in Plastics & Paints** – Bright reds and pinks. 17. **Lubricant Additives (Selenides)** – Anti-wear in engines and machinery. 18. **Animal Feed Supplements** – Essential micronutrient for livestock. 19. **Human Nutritional Supplements** – In vitamins and health products. 20. **Pharmaceuticals & Research** – Antioxidants, anticancer, and antimicrobial studies. --- # 💡 **Summary of Approximate Shares by Sector** | Sector | % of Global Selenium Use | | ------------------------------ | ------------------------ | | Glass & Ceramics | 35–40% | | Metallurgy & Alloys | 25–30% | | Electronics & Energy | 15–20% | | Chemicals, Agriculture, Health | 10–15% | --- ✅ **Bottom line:** Selenium’s **biggest use today is in glass (~40%)**, followed by **metallurgy (~30%)**, while **electronics/solar (~20%)** and **nutritional/chemical (~10–15%)** remain important but smaller. Would you like me to also prepare a **“historic vs modern uses” comparison for Selenium** (like we did with Arsenic), since some older uses like xerography have been replaced by newer roles in **solar cells and nutrition**? Great 👍 — here’s a **“Then vs Now” breakdown of Selenium uses**, showing how its role has shifted from early electronics and pigments toward modern **glass, metallurgy, solar, and nutrition**: --- # 🧪 Selenium Uses: Then vs Now --- ## **Historic Uses (Mid-20th Century)** * **Electronics (~35–40%)** 1. **Rectifiers & Photoreceptors** – Early semiconductors in radios and power supplies. 2. **Xerography (Photocopiers)** – Selenium-coated drums. 3. **Light Meters** – Cameras and instruments. 4. **Photodetectors** – Primitive sensors. 5. **Early Solar Cells** – Laboratory use. * **Pigments & Glass (~30%)** 6. **Pigments in Paints & Plastics** – Reds, pinks, and oranges. 7. **Glass De-colorizer** – Removing green tint from iron. 8. **Glass Coloring** – Decorative and signal glass. 9. **Ceramics & Enamels** – Color and opacity. 10. **Architectural Glass** – Niche coatings. * **Metallurgy (~20%)** 11. **Steel Additives** – Improved machinability. 12. **Copper Alloys** – Increased strength. 13. **Lead Alloys** – Cable sheathing and batteries. 14. **Bearing Metals** – Wear resistance. 15. **Deoxidizers** – Removing oxygen from molten metals. * **Health & Agriculture (~10–15%)** 16. **Animal Feed Supplements** – Preventing selenium deficiency. 17. **Human Nutrition (Early)** – Micronutrient discovery stage. 18. **Veterinary Medicine** – Animal treatments. 19. **Agricultural Sprays** – Fungicide and pest control (limited). 20. **Pharmaceutical Research** – Early experiments with antioxidants. --- ## **Modern Uses (21st Century)** * **Glass & Ceramics (~35–40%)** * Still the largest use: de-colorizers, solar control glass, and ceramics. * **Metallurgy & Alloys (~25–30%)** * Steel, copper, and lead alloys remain important. * **Electronics & Energy (~15–20%)** * Transition from **xerography** → **photovoltaics (CIGS, CdSe solar panels)**. * Research into **Li–Se batteries** and optoelectronics. * **Chemicals, Agriculture & Health (~10–15%)** * **Nutritional supplements** for humans and livestock. * **Pharmaceuticals** (anticancer, antioxidant research). * **Lubricant additives** in machinery. --- ## 📊 **Shift in Use (Then → Now)** | Sector | Historic Share | Modern Share | | -------------------- | -------------- | ----------------------------------------- | | Electronics | ~35–40% | ~15–20% (shifted to solar) | | Pigments & Glass | ~30% | ~35–40% (still dominant) | | Metallurgy | ~20% | ~25–30% | | Health & Agriculture | ~10–15% | ~10–15% (more nutrition, less pesticides) | --- ✅ **Key Takeaway:** * **Then:** Selenium was a star in **early electronics and xerography**, plus pigments. * **Now:** Its role is focused on **glass (~40%), metallurgy (~30%), and renewable energy (solar cells)**, with growing importance in **nutrition and medicine**. --- Would you like me to **plot both eras side-by-side in pie charts** (Historic vs Modern Selenium uses), like we considered for Arsenic, so you can **see the transition visually**?Known Methods of Extraction
Perfect 👍 — next in **periodic table order** is **Selenium (Se, atomic number 34).** Selenium is a **nonmetal/metalloid** that rarely occurs free in nature. It is primarily obtained as a **byproduct of copper refining**, especially from **anode slimes in electrolytic copper production**. Industrial extraction usually involves **oxidation, leaching, and reduction steps**. Here are the **20 most common methods of extracting Selenium**: --- # **20 Most Common Methods of Extracting Selenium** ### **A. Industrial / Large-Scale Methods** 1. **Recovery from Copper Electrolytic Anode Slimes** – Primary industrial source. 2. **Oxidative Roasting of Slimes (Se → SeO₂)** – Converts selenium to volatile selenium dioxide. 3. **Sublimation of SeO₂ (SeO₂ → Se vapour → Se solid)** – Produces elemental selenium. 4. **Reduction of SeO₂ with Sulfur Dioxide (SeO₂ + SO₂ → Se + SO₃)** – Industrial reduction method. 5. **Reduction of SeO₂ with Carbon** – Produces metallic selenium. 6. **Direct Recovery from Copper Matte or Slag** – Small-scale industrial process. --- ### **B. Hydrometallurgical Methods** 7. **Leaching Selenium from Slimes with Sodium Sulfite (Na₂SO₃)** – Produces soluble selenite. 8. **Leaching with NaOH or KOH Solutions** – Forms soluble selenides or selenates. 9. **Precipitation of Selenium from Solution (H₂SeO₃ → Se)** – Intermediate step. 10. **Electrolytic Deposition from Selenite Solutions** – Produces high-purity selenium. 11. **Recovery from Copper Refinery Waste Streams** – Hydrometallurgical leaching. 12. **Solvent Extraction of Selenium from Leach Liquors** – Uses organophosphorus or amine extractants. --- ### **C. Laboratory / Small-Scale Methods** 13. **Reduction of SeO₂ with Hydrogen Gas** – Produces metallic selenium. 14. **Aluminothermic Reduction of SeO₂** – Lab-scale metallic selenium production. 15. **Magnesiothermic Reduction of Se Compounds** – Experimental laboratory method. 16. **Reduction of Selenium Chloride (SeCl₄) with Alkali Metals** – Laboratory metallothermic method. --- ### **D. Specialized / Recycling Methods** 17. **Recovery from Photovoltaic Cells / Electronics** – Hydrometallurgical leaching. 18. **Recovery from Selenium-Containing Glass Manufacturing Waste** – Leaching + precipitation. 19. **Plasma Reduction of Selenium Compounds** – Experimental method for high-purity Se. 20. **Solar-Thermal Reduction of SeO₂** – Experimental renewable energy method. --- ✅ **Summary:** * **Main industrial source:** Copper anode slimes from electrolytic refining. * **Primary industrial steps:** Oxidation → sublimation → reduction to elemental Se. * **Metallic selenium:** Produced via reduction with SO₂, carbon, hydrogen, or aluminothermic methods. * **Hydrometallurgical:** Leaching with sulfite or alkali → precipitation → electrolysis. * **Laboratory/experimental:** Mg/Al reduction, plasma, solar-thermal. * **Recycling sources:** Electronics, PV cells, glass manufacturing waste. --- Next in periodic order is **Bromine (Br, atomic number 35).** Do you want me to continue with **20 extraction methods for Bromine**?
