Colligation Callback And Magnesian Reparation Of Boron Mud

Boron mud is the residue of industry producing borax using paigeite and camsellite. Compared with land clay, boron mud has some advantages such as the fine granularity, easy to be dispersed, high acid activity, easy for acid activity. Boron mud is light brown, insoluble and viscous. Boron mud is alkaline with a PH value between 8 and 10. Boron mud is mainly composed of magnesite and olivine. Magnesite is easily decomposed at high temperature, while olivine is a high temperature resistance material, which generally be used as the refractory. On the other hand, olivine is soluble in acid which influence its application. Because magnesite is rich in magnesium and olivine is rich in magnesium and iron, the industrial producing process of borax left most of the magnesium and iron, which are unable to useful in industry, in the residues.The synthetical reclaim and utilization of boron mud are mainly used in the concrete of building,mortar ,and road beds fillings,they can effectively improve the forepart intensity and other properties;and they can also be used to crank out boron mud ceramsite and beton with ceramsite concrete.The parameters of water absorption,antifreeze capability and soundness excelled than other ceramsite,boron mud ceramsite concrete's properties is haughtiness when compared to the common concrete's.Some scholars reclaim and utilizate boron mud and mainly use them in the compound coagulants.These compound coagulants dispose the boron mud and waste liquor according to a certain ratio.Compared to the common coagulants,they has the properties of rapid sedimentation rate and low disposal cost.We can also use boron mud as the mostly raw material,and join the major component of crystallite glass in it to make the crystallite glass,and we can get the crystallite glass which with the diopside,spinel,olivine and some corresponding crystal phases.Boron mud also can be used in the synthesis of refractory,such as use the magnesium raw material to synthesize the cordierite and magnesium olivine refractory. can contain crystallite glass which contain phases of diopside spinel olivine and so on, boron mud can produce insulating refractory and raw material of magnesium which use cordierite or magnesium olivine of preparation,comparing with cordierite using preparation of clay and pencil stone, not only a synthetic temperature of about 50℃lower than usual,but also the production quantity of iolite higher at the same testing temperature. Boron slag is widely used.For example,it can be used at metallurgical industry, flame-retardant agent, bulking agent and other trade. Seen from the nationwide, the technology and actuality of reclamation of boron slag is still not enough, but the development can not fill the require of comprehensive utilization on boron slag resource.In this thesis, we use acid leaching method employing hydrochloric acid and sulfuric acid as comparison to study the soaking rate of Mg from the boron. The results show that hydrochloric acid is high volatile then the concentration gets down quickly, so hydrochloric acid need long time for both leaching and heating, what is worse, it cannot destroy the crystal structure leading to a low production of magnesium. On the other hand, sulfuric acid has high acidity, concentration and oxidation which can totally destroy the mineral structure of olivine and then have a qualified solubility to magnesium. According to the comparison experiment, the dissolving out rate for acid soaking Mg by using the hydrochloric acid is maintained above 85%, which is not ideal. Sulfuric acid which need short time for leaching has high acidity concentration and oxidation what is better, it can completely destroy the crystal structure leading to a high production of magnesium, Mg by using the Sulfuric acid is above 95%. Sulfuric acid is a good boron mud solvent due to its low cost, not volatile and easy to recycle. the best industry condition for sulfuric acid dissolution method is concluded as follow: Using boron mud as our initial state, the dosage of H2SO4 is 5.304ml which the solid and liquid rate is 1:2 (this is 120% of the theoretical dosage of H2SO4), reactive time is 2h, reactive temperature is 100℃The MgO powder is prepared through the chemistry deposition by obtaining of the magnesium salt separated in the acid dipping method, in which PH is maintained at 7, then some quantity of PVA was added in it. The mixture was then stirred and heated. During the above process, some Na2CO3 was added into the mixture. After aging, filtering, and watered by the PVA solution, drying, and sintering, the MgO product was obtained. It was shown in the transmission spectra that, in the same time range, with the amount of PVA increased, the transmission was first decreased and then increased. When the amount of PVA is 12ml, the obtained sample has the maximal absorption, which means that the MgO powder has the best dispersibility and stability. When the amount of PVA is too low to meet the need of modification, the participation particles could not be encapsulated adequately by PVA. When the amount of PVA is too high, flocculation will occur among the excessive PVA molecules, which does harm to the quality of the product. Experimental results show that, with the deposition time of 40min, the MgCO3 sintering time of 3h, optimal craft is: the reaction temperature is 45℃, and the amount of the dispersant PVA is 12ml, the concentration of the scouring agent is 0.4%, the sintering temperature at 850℃.At last, we obtained SiO2 from the leavings distilled MgO from boron mud. By fusing leavings with alkali, and adding quantitative dispersant PVA, surranding the SiO2 particle can form a finite macromolecule limiting structure, namely formed a macromolecule protecting film, this restrained the growing of SiO2 particle effectively and avoided the particle reuniting, after this particles dispersed uniformity, then wash, filtrate, and calcine, can we get the silicon dioxide powder. Besides this, we also separated the mixed of iron and aluminium, which separated from the acid immersing solution, Under the above conditions, the purity of MgO final product can meet the requirement of high pure MgO. The XRD results show that the product of MgO SiO2 and Al2O3 have good crystalline quality. finally implement the synthetical reclaim for boron mud.