Study On Extraction Technology Of Humic Acid From Coal

This master's thesis takes weathered coal in yili as raw materials and extracts humic acid(HA)from weathered coal by acid extractant method.The main factors affecting the extraction yield are analyzed and studied,and the optimum technological parameters are determined.Taking the extraction yield of humic acid as an index to investigate the influence factors,as alkali concentration,soaking time and solid-liquid ratio of different extractants on the yield of humic acid.From the experimental data,the extraction effects of three groups of different extractants can be seen: the extraction effect of dilute hydrochloric acid and sodium hydroxide is better than that of dilute sulfuric acid and sodium hydroxide,while the extraction effect of potassium hydroxide and dilute sulfuric acid is between the dilute.Between hydrochloric acid and sodium hydroxide and between dilute sulfuric acid and potassium hydroxide.the maximum extraction rate can reach 74%.Therefore,when extracting free humic acid from weathered bituminous coal,the effect of using a set of extraction agent,hydrochloric acid and potassium hydroxide is used.it is good.he optimum laboratory conditions for the extraction of humic acid from weathered coal are 1.70 mol/L of dilute hydrochloric acid and 1.12 mol/L of sodium hydroxide.The optimum time for humic acid extraction from weathered coal is approximately 4 hours.About the optimum time for humic acid extraction from weathered coal is about 11 hours,and the solid-liquid ratio of weathered coal to hydrochloric acid is 2:25.The structure of humic acid was characterized by infrared spectroscopy and elemental analysis.The results show that HA is composed of five elements as C,H,O,N,and S.humic acid generally contains phenolic hydroxyl groups,hydroxyl groups,alcohol hydroxyl groups,enol groups,sulfonic acid groups,amino groups,mercapto groups,carbonyl groups,methoxy groups,and the like.These active groups determine the acidity,hydrophilicity,ion exchange capacity,complexing ability and high adsorption capacity of humic acid.Nitric acid was used as an oxidant and in the same time,different catalysts were added to evaluate its effect on the yield of humic acid.The experimental results show that the yield of humic acid can be significantly increased by using six different catalysts,among which titanium dioxide is the best.Sodium sulfite and ferric chloride increased the product extraction rate by 12% and 10% respectively,and the effect was lower than that of titanium dioxide catalyst.