含釩石煤礦高效清潔提取五氧化二釩

魏昶 李旻廷 李興彬 李存兄 鄧志敢

摘 要：本研究采用XRD、SEM、BES、TG-DTG等檢測手段，對多個地區(qū)（四川、貴州、甘肅、湖南）的含釩石煤進行了礦物學(xué)研究。研究表明，石煤中的主要礦物為石英、云母、粘土；各地石煤礦的化學(xué)成分、釩賦存狀態(tài)、不同價態(tài)釩的分布差異較大，但釩主要賦存于鋁硅酸鹽礦物中。采用常壓強化浸出工藝，對多個地區(qū)石煤進行了提取釩的工藝技術(shù)研究。結(jié)果表明，湖南、貴州、四川、甘肅等地石煤礦中釩浸出率可達80%、82%、62%、55%以上，含氟離子助浸劑的加入有利于含釩礦物的強化離解；釩浸出率與碳質(zhì)成分的含量及二氧化硅含量有關(guān)。廢酸回收率達到83%以上，釩離子和鐵離子截留率分別達到93-95%和92-94%；釩萃取率和反萃率分別達60%和70%以上。酸浸渣用于制備建筑用陶粒和磚，產(chǎn)品達到優(yōu)等品的等級要求。開展了日處理100kg含釩石煤礦連續(xù)浸出—連續(xù)萃取/反萃—精釩制備擴大實驗，釩浸出率可達82-83%，重現(xiàn)了小試結(jié)果；8級逆流萃取/反萃后，釩回收率達96.3%；產(chǎn)品五氧化二釩純度為99.01%；全流程釩直收率達80%以上。研究了U，Th，Ra，K等四種放射性核素在全流程的走向及分布。結(jié)果表明，石煤中93.06%的U進入溶液。而經(jīng)過萃取反萃后，98%左右的U在貧有機相中富集；而75-77%的Th，Ra，K三種放射性核素在浸出過程中滯留于渣相中，在后續(xù)萃取/反萃過程中的分布與U是一致的。常壓強化浸出—萃取工藝為實現(xiàn)石煤資源的高效清潔利用提供了一條可行的技術(shù)路線。

關(guān)鍵詞：石煤； 釩； 強化浸出； 萃取； 放射性核素

A clean and high effective technology of vanadium pentoxide extraction from vanadium-bearing stone coal

Abstract：The present project is a continuation of the previous study of “Extraction of vanadium from stone coal under pressure field and comprehensive utilization of resources”. On the base of the previous research， an intensified leaching-solvent extraction-precipitation-calcination process was proposed. XRD， SEM， BES and TG-DTG were used to analysis the mineralogical of the vanadium-bearing stone coal from the different regions. The research showed that quartz， mica and clay is the three major minerals， though the chemical component， vanadium deposit， and the distribution of difference valance vanadium are quite different between the stone coal from different areas， vanadium mainly occurs in aluminosilicate minerals. The intensified leaching technology was employed to extracting vanadium from the vanadium-bearing stone coal from different regions. The results showed that， the vanadium leaching ratio were 80%， 82%， 62% and 55% for the stone coal from Hunan， Guizhou， Sichuan and Gansu provinces， respectively. The fluoride aid-leaching reagent can improve the leaching rate of vanadium. Vanadium leaching ratio is related to the carbon and silica contents in the mineral. More than 83% sulfuric acid could be recovered from the leaching solution， and the vanadium and iron rejection were within 93-95% and 92-94%， respectively. In the solvent extraction and stripping process， vanadium single extraction and striping ration were more than 60% and 70%， respectively. The leaching residue was used to preparation of building brick and ceramic， the quality of these products achieved through quality standards. Continuous expanding experiments of 100 kg/d stone coal every day was carried out. The vanadium leaching ratio was 82-83%， and vanadium extraction was 96.3% with 8 stages solvent extraction and stripping as well as the purity of V2O5 product was 99.01%. Vanadium recovery in all processes is more than 80%. The direction and distribution of the radioactive nuclide of U， Th， Ra and K were studied also. The results showed that 93.06% of uranium dissolved in solution and 98% of uranium was enrichment in the organic phase. While 75-77% of Th， Ra， and K retain in the residue， and their behavior in solvent extraction-stripping process was as same as uranium. The atmospheric intensified leaching-solvent extraction process provides a feasible technology route for recovery vanadium from stone coal.

Key words：stone coal； vanadium； intensified leaching； solvent extraction； radioactive nuclide

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