Effect of composite binder on quality of iron concentrate pellets
In order to fully explore the advantages of organic binders on the quality improvement of iron concentrate pellets and make up for the shortcomings of organic composite binders in weakening the compressive strength of finished pellets,vermiculite,sodium carboxymethyl cellulose(organic binders)and bentonite are compounded to explore the effect of composite binders on the quality of iron concentrate pellets,and the mechanism of vermiculite to improve the strength of finished balls is explored with the help of SEM and thermogravimetric analysis.The results show that,when only 1％bentonite is added without organic binders,the drop strength of pellets is only 1.5 times/(0.5 m),the compressive strength is 8.2 N/P,the burst temperature is 550 ℃,and the strength of finished pellets is 3 121 N/P when the preheating temperature is 950℃and the roasting temperature is 1 200 ℃.When the amount of bentonite is fixed,with the increase of the proportion of organic binder to 0.12％,the drop strength of green pellets can be increased to 8.0 times/(0.5 m),and the compressive strength can be increased to 11.3 N/P,but the bursting temperature of green pellets can be reduced to 395 ℃,and the strength of finished pellets can be reduced to 2 465 N/P;After adding 0.03％vermiculite+0.12％organic binders+1％bentonite,the quality index of pellets is the best,the dropping strength of pellets can reach 6.5 times/(0.5 m),the compressive strength is 13.4 N/P,and the bursting temperature is 362℃.The strength of finished pellets can be increased to 2 764 N/P under the same conditions.The results of SEM and thermogravimetric analysis show that the expansion of vermiculite can continuously expand and fill the pores in the pellets,and form a liquid phase during the roasting process,which is conducive to the growth of solid-phase diffusion crystals,reduce the porosity of the pellets,and improve the compressive strength of the finished pellets.
万方数据
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