Determination Of Organic Acids In The Leaching Liquid Of Low-grade Pyrolusite With Cane Molasses And Influence Of Impurities On The Current Efficiency Of Electrolytic Manganese

The leaching technology of low-grade pyrolusite by organic matter has the advantage of efficient,low energy and environmental,and has become the main research direction of hydrometallurgy in manganese industry.In the process of leaching pyrolusite by using cane molasses as reducing agent,we found that the color of the leach liquor is so deep that cause corrosion to the electrolytic plate and equipment,which Seriously affected the popularization and application of the leaching technology of low-grade pyrolusite by cane molasses.Aiming at the shortcomings of the technology,this paper measured organic acid content in the molasses and the leaching liquid,handled dechlorination and discoloration to cane molasses,treated purification to the leach liquor.And the paper Investigated the influence of organic acids on the current efficiency of electrolytic manganese.(1)The high performance liquid chromatography(HPLC)method is used for quantitative analysis to several kinds of organic acids of cane molasses and its leach liquor.The results showed that there are nine kinds of organic acids including tartaric acid,formic acid,malic acid and aconitic acid,acetic acid,lactic acid,citric acid,succinic acid and fumaric acid.The molasses is most abundant in citric acid and aconitic acid,Content,respectively,is 3.81g/L and 3.20g/L,succinic acid is 1.27g/L,acetic acid is 0.52g/L,formic acid is 0.26g/L,lactic acid is 0.10g/L,fumaric acid is 0.02g/L.Most abundant in the leach liquor is formic acid,whose content is 3.13g/L,Respectively,the contest of acetic acid,tartaric acid,citric acid,aconitic acid,succinic acid,fumaric acid,malic acid and lactic acid is 0.73 g/L,0.55 g/L,0.26 g/L,0.21 g/L,0.19 g/L,0.05 g/L,0.04 g/L,0.01 g/L.In the process of Determination,The recoveries of organic acids is between 94.52%and 105.66%.The relative standard deviation is between 1.12%and 4.94%.(2)On the current efficiency,the article explored the influence of organic matter,including formic acid,acetic acid,tartaric acid,aconitic acid,citric acid and glucose and sucrose,and the impurity in the electrolyte,such as SDD,sodium sulphide,cerium ion,phosphate ions and fluorine ion.The experimental results show that,It can improves the current efficiency of electrolysis process that the tartaric acid content in electrolyte is less than 1.5%,aconitic acid content is less than 0.6%and citric acid content is less than 1.2%.The current efficiency will decline if the content more than the data above,and resulting in a decline in the quality of the electrolytic manganese.The citric acid can improve current efficiency of electrolysis process.We can add the citric acid which Content is less than 1.2%to achieve the goal of reducing the selenium dioxide,so that reduce the processing cost and pollution,The experiment results showed that the optimum content of the citric acid is 0.5%,and the selenium dioxide is 0.015g/L.(3)In the weak alkaline environment,cuprous oxide can be made by the technique using the organic of cane molasses reductive copper sulfate,it can generate cuprous chloride by reacting with chloride ions.This technique can achieve the purpose of removing chlorine ion.Using single factor experiment,the effect of five factors on removal rate of chloride ions was investigated.The five factors include copper sulfate dosage,pH value,reaction temperature,reaction time and the amount of sulfuric acid.The paper ues orthogonal test to obtain the optimum conditions that dosage of copper sulfate is twice its equivalence,Potential of hydrogen is 8,reaction temperature is 90?,reaction time is 8g/L,the highest removal rate of chloridion is 89%.(4)The paper studied the treatment of decoloring the leaching liquid by activated carbon,investigated the effect of Activated carbon dosage,reaction temperature and reaction time on decolorization rate,and conducted a study of dynamics.The experimental results show that decolorization rate increased with the increase of dosage of activated carbon present linear upward trend.With the increase of reaction temperature,the decolorization rate firstly increases and then decreases,the highest value is 62.9%on 70?.With the extension of reaction time,the decolorization rate firstly increases and no longer changes after 30min.The kinetic studies showed that the pseudo second-order rate equation and diffusion dynamics could fit the experimental data well.The equilibrium was reached in 30 min.After processed by removing chlorine and reacted with mineral powder,the decoloring ratio of molasses is 45%,and finally reach 80.4 after decolorizing.