| In this paper,we get magnesium hydrate by ammonia method and sodium hydroxide method.explore the best process parameters and the best reasonable process flow.in the end,we detect and characterize the production.First,we summarize the characters and usages,methods to produce,foreground of development.in the abstract,.through experiments,we find out the best process parameters and the best reasonable process flow,then detect and characterize the production.With the precipitate of ammonia,the best conditions are CMg2+:concentration 40g/l,temperature 40℃,2.5 times ammonia,20% seed-crystal,time 60mins;magnesium hydrate purity is 99.23%,other grades are up to stuff of occupation standard of I;TEM shows that magnesium hydrate crystal grain is resembling fiber,grain length is 200nm,diameter 6.7nm,length-diameter ratio 30.With the precipitate of sodium hydroxide,the best conditions is CMg2+:concentration 40g/l,temperature 90℃,1 time seed-crystal,time 60mins;Result of XRD goes all way with the normal curve,magnesium hydrate content is more than 99%,average Cl content is 0.097%,other grades are up to stuffs of occupation standard of I;TEM shows that magnesium hydrate crystal grain is resembling hexagon platelet,grain diameter is 250-310nm,thickness is 10nm.it is sub-micron superfine magnesium hydrate,can be used as fire regardant.Slurry produced by ammonia method can be filtered well,but as the PH descends,filtering performance turns to be difficult.After seed-crystal be added in,it can accelerate the growth of crystal,and improve the filtering performance.Slurry produced by sodium-hydroxide method can not be filtered without seed-crystal,when seed-crystal is added in,it can accelerate the growth of crystal,and improve the filtering performance.The circulation of seed-crystal can weaken the glomeration of magnesium hydrate,and the diameter of magnesium hydrate grain become small.Study and production of magnesium hydrate can brrow ideas from this paper.Sodium hydroxide... |
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