The Influence Of K And Na On Coking Characteristics Of Blending Coal And Properties Of Tamping Coke

Qinghai Muli coal is a kind of high-alkali coal with a certain caking capacity and a high amount of K and Na.In order to make good use of the high-alkali coal for tamping coking,it is absolutely necessary to study the impact of K and Na on coking characteristics of blending coal and properties of tamping coke.The purpose of this dissertation was to research the impact of K and Na on coking characteristics of blending coal and properties of tamping coke and relatedly mechanism,explore effective ways to reduce the influence of Na and K in coal and finally provide some ideas for the use of high-alkali coal in coking.First,a certain amount of alkali metal carbonates were added into the blending coal of 5.5 m tamping coke oven in Lian Gang.Then the influences of K or Na on the volatile matter,the caking and coking properties and the pyrolysis of blending coal were studied.5 kg tamping-coking experiments were carried out.Then the influences of K or Na in blending coal on the cold strength,the thermal properties,the microcrystal structure and coke optical texture of coke by 5 kg tamping-coking experiments were studied.And the mechanism of coke properties effected by K or Na was investigated from the coking process.Then the research of reducing the influence of K or Na in blending coal on coking characteristics of blending coal and properties of tamping coke was done by adding H₃BO₃ or TiB₂.The effect of the two methods was compared.Finally,5 kg tamping-coking experiments by using blending coal with the addition of Qinghai Muli high-alkali coal and TiB₂ were carried out based on the previous studies.And we got the following conclusions:?1?K or Na catalyzed the pyrolysis of blending coal and reduced the pyrolysis activation energy at 400?-600?.The volatile matter of blending coal increased,the G and Y of blending coal both reduced with the increasing amount of K or Na in blending coal.K and Na made gelatinous body decomposed,made the the amount of gelatinous body reduced,made the caking of blending coal weakened,made the the amount of volatile matter increased.As a result,the properties of coke obtained became more poorer.The results of XRD showed that K or Na could reduce the degree of graphitization of coke,and decrease the Lc of coke.The analysis of coke optical texture indicated that K or Na could lead to the increase of the isotropic texture.K or Na in blending coal had a catalytic effect on the solution-loss reaction of coke.And the thermal properties of coke bcame worse with the increasing amount of K and Na in blending coal.?2?The influences of K or Na in coal on the thermal properties of coke could not be reduced by adding boric acid in blending coal.But the influence of K or Na in coal on the thermal properties of coke could be reduced by adding TiB₂ in blending coal.The CRI of coke reduced and the CSR of coke increased with the increasing amount of TiB₂ in blending coal.Adding 0.5% TiB₂ could offset the influence of 0.8% K in blending coal on the thermal properties of coke.Adding 0.9% TiB₂ could offset the influence of 0.8% Na in blending coal on the thermal properties of coke.?3?The CRI of coke was 43.2% from 35.0%,the CSR of coke was 48.5% from 56.5% when coking by 30% Qinghai Muli high-alkali coal and 70% blending coal.The influence of 30% Qinghai Muli high-alkali coal on the thermal properties of coke could be offset by adding 0.9% TiB₂.