The influence of simultaneous adsorption of potassium and sodium vapours on coke structure and performance

Abstract

Alkali metals are one of the important factors promoting the degradation of coke in blast furnace. Previous studies usually focused on the properties of coke affected, respectively, by K and Na separately, while K and Na will simultaneously affect coke performance in the actual production of blast furnace. Through simulating the actual situation where coke is affected by K and Na vapours simultaneously in blast furnace, the evolution of coke structure and thermal properties (CRI, CSR) after alkalisation with different proportions of K and Na vapours are revealed in this study. Results showed that coke structure was broken when the proportion of alkali vapours reached 3%, and coke fine formation rate increased with the increase of K vapour, indicating that K vapour caused a great damage to coke structure; CRI of coke reached the highest and CSR the lowest when K/Na ratio was 3/7. It was observed with SEM/energy dispersive spectrometer that K and Na existed in both mineral matters and carbon matrix; nepheline, generated when coke reacted with alkaline (K, Na) vapours, was determined by XRD. The content of K and Na in nepheline is dependent on the ratio of alkaline (K, Na).

Analysis of the Coke Particle Size Distribution and Porosity of Deadman Based on Blast Furnace Hearth Dissection

“…Alkalis could destroy coke structure, reduce coke strength and break it into small pieces and fines. 29,30) Thus, improving the quality of feed coke, reducing the alkalis load and making the hightemperature gas pass through the center of the blast furnace using the reasonable burden charging program were the core operation of extending the life of blast furnace hearth.…”

Effect of the Particle Size of Iron Ore on the Pyrolysis Kinetic Behaviour of Coal-Iron Ore Briquettes

“…At present, researchers generally believe that the minerals that can improve coke reactivity mainly include transition metals [16,17], alkali earth metals [18,19], and alkali metals [20][21][22]. However, alkali earth metal and alkali metal minerals have been studied quite thoroughly as catalysts, and these two kinds of minerals could destroy the lining of a blast furnace and aggravate the degradation of coke during the process of blast furnace production [23][24][25][26]. Therefore, ferro-coke was developed and iron, as the target product of blast furnace production, did not cause many adverse effects when iron ore was added to the coke [26].…”

Microstructure and Phase of Carbon Brick and Protective Layer of a 2800 m³ Industrial Blast Furnace Hearth

“…Many of the challenges are connected to the high level alkalis and zinc constituents, such as increasing of coke reactivity and coke degradation, forming scaffolds on the inner walls of the furnace, the tuyere upward-warp and the erosion of lining, etc. 1,3,4,[12][13][14][15][16][17][18][19][20][21] Previous researches on alkali metals and zinc in the blast furnace mainly focused on their enrichment and damage behavior to the raw materials and fuels, [13][14][15][16]19,20) but there is few studies on the carbon brick corrosion by alkalis and zinc at the…”