Study On Preparation Process And Metallurgy Properties Of New Ironmaking Material-Iron Coke Hot Briquette

Climate warming,resource exhaustion and environmental degradation have been the largest challenges all over the world with the rapid development of global industries in twenty centry.High energy consumption and carbon dioxide emission increasing greatly have become focus issue widely concered by whole society.The steel industry is one of important pillar industries for national economy and society development.Simultaneously,during quite a long period of time in the future,the blast furnace-converter process plays a dominate role in the whole steel production.And blast furnace is responble for the largest energy consumption and biggest carbon dioxide emission amonge the whole steel production system,which account for about 70%and 80%of the whole steel production system,respectively.Therefore,blast furnace process is the critical link of steel industry in energy conservation and emissions reduction.In this paper,according to present situation of steel industry,resource and energy sources in China and based on the conditions of raw materials in our country,the new process of Iron Coke Hot Briquette(ICHB for short)preparation was put forward,which is a new typical ironmaking burden.Under laboratory conditions,the new process of ICHB preparation and its optimization countermeasures were investigated.Simutenously,matellurgy properties of ICHB were studied,which mainly included CRI and CSR of ICHB,effects of ICHB on coke hot metallurgy properties,and effects of ICHB on softening-melting and dripping properties of comprehensive burden.With systematical researches,some conclusions were obtained as follow:(1)With the increase of iron ore ratio,the compressive strength of ICHB is increased first and then decreased.When the ratio of ore powder is 15%,compressive strength of ICHB reaches maximum value,namely 3490.89 N.The compressive strength of ICHB is increased with the increase of bituminous coal ratio,which reaches 3985.17 N with 70%bituminous coal added.With hot briquette temperature increasing from 150℃ to 350℃,the compressive strength of ICHB is increased,namely from 2777.22 N to 4305.40 N.With the increase of carbonization temperature,the compressive strength of ICHB is decreased first and then increased.When carbonization temperature is 1100℃,compressive strength of ICHB reaches 3424.00 N.The compressive strength of ICHB is increased first and then decreased with the increase of carbonization time.When carbonization time is 4 h,the compressive strength of ICHB occupies maximum value,namely 3518.80 N.(2)Considering practical production,optimization combination condition of ICHB preparation process is A4B4C4D4E4 via orthogonal experiment,namely 15%iron ore,65%bituminous coal,300℃ hot briquette temperature,1000℃carbonization temperature,4 h carbonization time.With A4B4C4D4E4 condition,the compressive strength of ICHB reaches 5048.50 N.(3)CRI and CSR of ICHB were studied with the condition of GB/T 4000-2008.The results showed that the CRI of ICHB is 62.41%and that the CSR of ICHB is 10.65%.With acertain amount of ICHB added in coke,the effects of ICHB on coke hot properties were researched.With the adding ratio of ICHB increasing,the weight loss ratio of coke after reaction is decreased and then kept constant.The coke strength after reaction is increased firstly and then unchanged.The weight loss ratio of ICHB gradually is decreased,but the variation is small.The ICHB strength after reaction is gradually increased.Therefore,ICHB has certain protective effect for coke,which is obvious with ICHB ratio no more than 10%.(4)With the increasing of ICHB charging ratio,softening start temperature(T4)and softening end temperature(T40)of comprehensive burden are both decreased,and the softening temperature interval(T40-T4)are widened increasingly from 206.3℃ to 218.9℃.Melting start temperature(Ts)is increased and dripping temperature(TD)is decreased.Melting temperature interval(Td-Ts)is decreased from 171.1 ℃ to 124.8 ℃,namely the conhesive zone narrowing.The dripping ratio of comprehensive burden is increased first and then decreased.When the charging ratio of ICHB is 30%,the dripping ratio is obtained the maximum value,namely 40.58%.S-value of comprehensive burden is decreased,which indicate that the permeability of comprehensive burden is improved.Considering softening-melting and dripping properties as well as permeability performance of comprehensive burden,proper charging ratio of ICHB in comprehensive burden is about 30%.