Study On Quality Control Of The Needle Coke

ObjectivePotassium,lead,magnesium,zinc,copper,manganese and other trace metal elements of needle coke were determined by Flame Atomic Absorption Spectrometry,and the sulfur content of needle coke was determined by tube furnace method,volatile matter productivity was determined by calcination method,true density was determined by anhydrous ethanol.These routine index were determined to formulate quality standard for needle coke.MethodsAfter calcined needle coke samples,join Li2B4O7 flux,releasing agent lanthanum solution,using flame atomic absorption spectrometry determination of needle coke samples in potassium,lead,magnesium,zinc,copper,manganese and other trace metals.The generated sulfuric acid was titration with the measured concentration of sodium hydroxide,and the content of sulfur in the needle coke was determined.The crucible with needle coke sample was calcined at 850 min in a high temperature furnace at a temperature of 7,and the mass percentage of the sample mass is reduced by subtracting the moisture content,and the volatile yield can be obtained.The calcined sample needle coke into the volumetric flask,adding anhydrous ethanol,true density by mass of ethanol capacity volume of the bottle,anhydrous ethanol density,needle coke samples quality,discharge for needle coke.ResultsThe 2 batch of needle coke samples were determined by the method,and the FAAS determination of needle coke samples of trace metal elements and the entry-exit inspection and quarantine industry standard method SN/T1829-2006(ICP-AES)measurement results are basically the same.The relative standard deviation(n=10)was 0.63%~3.4%,and the recoveries were between 98%~104%.The content of sulfur in needle coke is 0.71%,RSD is 0.93%,the content of sulfur is,the content of sulfur is,the content of sulfur is determined by the measured concentration of sodium hydroxide standard titration solution.Two results of repeatability test the difference was less than 0.05%,in accordance with the provisions of state GB/T387-90,two results repeatability test the difference was less than 0.2%,in accordance with the provisions of state GB/T387-90.The difference of the two results of the repeatability test of volatile yield was less than 0.3%,in line with the state regulations SH/T0026-90,the difference between the two results of reproducibility test was less than 0.5%,but also in line with the state regulations SH/T0026-90.The difference of the two results of the determination of the true density of the needle coke is less than 0.01 g/cm3,which is in accordance with the state regulations SH/T0033-90.ConclusionsDetermination of trace metal elements in samples with FAAS needle coke.The precision and accuracy of the method are satisfactory.The content of sulfur in needle coke was determined by tube furnace method,the operation is convenient and quick,the sample quantity is accurate,and the result is accurate and reliable.And the burning time is only half an hour,the analysis is fast.In the national standard range,the crucible cover on the quality of needle coke has important effect on Determination of volatile matter.It is found from the experiment that the repeatability of the measurement results of the volatile matter is not more than the repeatability limit specified by the national standard.The test method for the true density of needle coke in anhydrous ethanol is simple and practical,and it is not affected by external factors,and the permeability of ethanol is stronger than that of water.