Study Of The The Mojiang Silicate Nickel Mine Wet Process Test

There are some good performance of nickel,such as being unbearable rusty,high melting point,powerful magnetism.Nickel is also a important raw material of various special steel,thermostabilization alloy,resisting rusty alloy,magnetic alloy and kentanium alloy.These products have been application widely in aviation,space flight,machinofacture,electric meter and chemistry.For this reason,That is why nickel has been classified as strategy goods and materials.Nickel resources is mainly come from sulfuration nickel deposit and oxidize nickel deposit.In those resources,about 39.4 percent is sulfuration deposit and about 60.6 persent oxidize deposit.But 60 percent of nickel products are produced form fulfuration nickel deposit.With economic developing and extracting nickel ore continuously,the requirement to nickel product is becoming intense.The sulfuration nickel deposit decrease slowly.Since 1950,the demands of nickel is increasing average 4 percent every year.However,additional reserves of sulfuration deposit is obvious low than its consumption.With the rapid progress of mineral process,the large oxidize nickel deposit will ture into primary source of nickel yield increased.At present time,there are two methods which can utilize the oxidized nickel ore in the world.That is pyrometallurgical technics and hydrometallurgical technics.And the hydrometallurgy method has make rapid progress especially in this years.Many new projects about oxidized nickel ore have all chosen the hydrometallurgical technics,such as Murrin Murrin and Bulongs projects in Australia.The hydrometallurgical techincs have its own dominant features in the aspect of environment,coefficient of recovery of metal and constitute of products.Hydrometallurgical technics to utilize the oxidized nickel ore will have better perspective in the future.MoJiang nickel ores is typical weathering silica nickel deposit,In general,some nickel adsorb mainly in laterite on the upside of deposit,some consist in silica minerals.The object of study of this thesis is mainly silica nickel ore.Nickel consist mainly in silicate minerals.Therefor it is difficult to recover and collect nickel with traditional concentrate method.Based on the results from the mineralogical of the run-of-mine,the mineral contained nickel is sharp serpentine in this ores.The sharp senpentine contained nickel is about second to third in serpentine of ores.Other one to third isn't containe nieckel.The nickel distributed to serpentine is about 87 percent in nickel ore.Another 13 percent nickel enter the corrosion minerals such as nontronite,chlorite and so on.The average grade of nickel is 0.98%,cobalt 0.018%and oxidized magnesium 31.41%in the ore.There are about 7～10 percent iron in serpentine.This thesis is to use hydrometallurgical technics to recover the nickel and cobalt from silicate nickel mineral.The technologies including reduction roasting--calcine being ammonia leacing,crude ore being acid leaching at normal atmosphere and crude ore being pressure leaching have been adopted in this thsis.The nickel and cobalt has been recovered by precipitate.After reduction roasting,the calcine has been leached by ammoniacal liquor constituted by NH₃·H₂O and(NH₄)₂CO₃.The leaching rate of nickel and cobalt is only 40 persent and 25 percent respectively.And the leaching rate of niekcle,cobalt and iron is up to 73.28 percent,73.39 percent and 13.59 percent respectively at normal atmosphere.At pressure leaching and the leaching system be closed,the leaching rate of nickel,cobalt and iron 75.14 percent,70.6 percent and 5.25 percent respectively.In the exist of air,the leaching rate of nickel,cobalt and iron is 78.58 percent,76.02 percent and 8.6 percent respectively at pressure leaching.The nickel and cobalt in leachate has been recoveryed.The final product is nickel sulphide.The grade of nickel and cobalt is average 28.94 percent and 0.30 percent respectively and the total recovery rat of nickel and cobalt is 76.57 percent and 69.59 percent respectively.The quest research on treating the leached residue and waste water obtained had been made.To use magnetic separation method ethier recover the iron contained in the residue and also to decantate the residue in order to avoid the damage the environment.Because there are too many magnesium in liquid after precipitate nickel and cobalt from leachate,the liquid hasn't to take advantage of recirclly.Magnesium can be removed as hydroxide using calcium hydroxide(Ca(OH)₂)and the precipitate produced is a mixture of magnesium hydroxide(Mg(OH)₂)and gypsum(CaSO₄·2H₂O).A set of properties of the precipitate that can characterize a material as a filler have been compared with other commercial products.The magnesium hydroxide-gypsum precipitate proved to be promising for application as a filler.After removal of magnesium by chemical precipitation using calcium hydroxide,the water can be reused.This method can save the valuable water resource greatly.We can draw a conclusion according to the results from experiments that the hydrometallurgical technics that consist of stress acid leaching and nickel and cobalt precipitated using sulphate sodium from leachate is feasible to treat the oxidized nickel ores.