Experimental Study Of Comprehensive Utilization Of Low Calorific Value Stone Coal In Shangluo

Stone coal is a low-grade anthracite with low-carbon, low calorie, high hardness, high-sulfur, high ash and other characteristics. It often associated with traces of vanadium, molybdenum, uranium, phosphorus, silver and other valuable elements. China is rich in stone coal resources which containing vanadium. However, Stone coal development and utilization degree is not high, mainly for the vanadium recovery and power generation. To carry out comprehensive utilization of stone coal resources, improve resource utilization is an important research topic.In view of the low calorific value stone coal containing vanadium in Shangluo, on the basis of the relevant literature, calculated fluidized bed combustion for power generation stone coal and anthracite coal blending ratio, preparation of ash in the laboratory are adopted to simulate the blending combustion method. Focus on the direct combustion of ash and sulfur fixation burning ash of wet process vanadium extraction experiment was carried out.In the stone coal of occurrence vanadium with complex form, vanadium extraction process regional differences. This study analyses the basic characteristics of stone coal ash, through exploring experiment and conditional experiment, finally determine the "burning ash- acid leaching- crystallization recovery of potassium- neutralizing reduction- vanadium extracting and vanadium anti extracting- vanadium precipitation-calcination and get V2O5 products", the technological process can effective recovery of stone coal burning ash of vanadium, and recovery of potassium at the same time. And the main technical parameters of each process were determined, the results are as follows:(1)Stone coal and anthracite coal mixed in a ratio of 3:1, through direct combustion and join Ca O sulfur fixation combustion get two burning ash. The burning ash leached in acid directly in the way of countercurrent washing and circulating leaching, at the same time to join help infusion to strengthen leaching, the experimental results show that with stirring speed was 200 rpm, infusion of 0.5% 1# leaching agent + 4.5% 2# leaching agent, dosage of sulfuric acid 32.5%, the liquid-solid ratio 2:1, leaching temperature 90?, leaching time 16 h, the direct combustion ash vanadium leaching rate was 77.61%. With dosage of sulfuric acid 40%, the liquid-solid ratio 3:1, leaching temperature 90?, leaching time 6h, the sulfur fixation burning ash of vanadium leaching rate was 72.86%.(2)Focus on sulfur fixation burning ash leaching liquid crystallization by recovery of potassium sulfate production has carried on the experimental study. After crystallization of sulfur fixation burning ash leaching liquid, using stone coal ash neutralization, and the neutral dregs return to leaching, the supernatant after lime neutralization, iron reduction for level 4 counter-current extractions. Extraction solvent composed of 12.5% P204 + 5% TBP + 85% sulfonated kerosene, phase ratio(O/A)= 2:1, extraction concentrate p H is 2.5, V2O5 concentration of raffinate is 0.016 g/L, V2O5 concentration of loaded organic phase is 2.89 g/L, V2O5 extraction rate was 99.3%.Use 4 stage countercurrent re-extraction preparation vanadium precipitation stoste, re-extraction agent is 1.5mol/L sulfuric acid, phase ratio(O/A) = 4:1, V2O5 concentration of strip liquor is 8.492g/L, V2O5 concentration of organic phase is 0.067 g/L, V2O5 re-extraction rate was 96.9% on average.(3)Under the condition of acidity of 0.6mol/L and 60? to join vanadium precipitation stoste 200g/L sodium chlorate solution oxidation and then sink vanadium. Vanadium precipitation stoste temperature is 92?, with 25% ammonia adjust p H value to 1.7. Vanadium precipitation rate was 97%, V2O5 concentration of pure vanadium products is 98.13%. Red vanadium pyrolysis recovery greater than 99%, the total vanadium recovery is 71.69%~71.69%. The V2O5 content of pure vanadium product at 98.13% witch meet the national standards of GB3283-87.This study laid the groundwork for further developing industrial experiments, the process of extracting vanadium studied in this paper easy to realize continuous operation with high vanadium recovery and less "three wastes" emissions. Relevant results of the comprehensive utilization of low calorific value of Shangluo stone coal economic evaluation has application value.