Experimental Study On Preparation Of Pellet From Self-produced Iron Concentrate Of Jiuquan Iron And Steel Company

The production of Jiuquan Steel's pellet has the problems of low equipment production,uneven product quality and expensive iron ore concentrate.These problems become the main factors that restrict the development of Jiuquan Steel and reduce the cost of production.Therefore,how to use self-produced iron ore concentrate and the application of advanced pellet production process,has become an important issue in the development of Jiuquan Steel.The self-produced iron ore concentrate of Jiuquan Steel has low iron content,high content of gangue and associated minerals,coarse grain size and small surface roughness.Therefore,there are some problems such as poor fineness and complicated preheating roasting process.This topic with jiuquan Steel's self-produced iron ore concentrate mock chain grate machine-preparation of pellets as the research route of rotary kiln,on utilizing the three produced pellets of iron concentrate production of barite in pellet preheating roasting process and parameters of the mechanism for experimental research.The first step is to analyze the physical and chemical properties of the pelletizing raw materials.The second step is to determine the three kinds of iron ore concentrates by single factor experiment on the parameters of the pelletizing parameters?grinding,raw water,bentonite ratio and pelletizing time?.The third step,select the appropriate preheating roasting parameters by experimental study on these three kinds of iron ore concentrate preheating ball and roasting ball performance.The fourth step,by study on mechanism of action of barite in the pellet preheating and roasting in the process of pellet production,I analyzed the resolve action of barite during pellet production and influence of barite content on pellet preheating.The following conclusions are drawn from the experiment:1.It can improve the three kinds of iron ore particle size composition,surface roughness and into the ball by damp milling.After the damp milling,the optimum parameters of the three kinds of iron concentrates are:8.5%of fresh water,1.5%of bentonite,10min of pelletizing time;9.5%of weak magnetic water and 1.5%of bentonite ratio;the ball time 12min;strong magnetic water 9.5%,bentonite ratio of1.5%,the ball time 10min.2.By compare performance of three types of concentrate preheating roasting,the weak magnetic energy can obtain high-quality pellets in the lower temperature and shorter time,pre-calcined preheating roasting performance take the second place,the magnetic makes a worst effect which is mainly because its iron mineral composition and preheating roasting required high temperature and long time,narrow roast temperature range,low preheated roasting ball compressive strength.The preheating roasting parameters of the three types of iron ore concentrate pellets are:940?,12min,calcination system is 1275?,12min;the preheating system suitable for the weakening is 940?,10min,1250?,10min;strong magnetic suitable preheating system for1030?,12min,1300?,12min.3.With the increase of the content of BaSO₄ in the pellets from 0%to 5%,the compressive strength of the pellets after the preheating did not change obvious,and the compressive strength of the pellets after roasting increased first and then decreased.The value of compressive strength reaches the maxi when the content of BaSO₄ is 1.5%.Suitable BaSO₄ content can optimize the pellet production system.BaSO₄ decomposed in pellets roasting,Fe₂O₃ and SiO₂ in roasting ball can make BaSO₄ decompose,the point of BaSO₄ phase transition is the main reason of why it happen,and the main phase,Fe₂O₃ and BaSO₄,can generated BaFe₁₂O₁₉ during roast of pellets.