Experimental study on chromite ore decomposition by KOH-KNO3 and NaOH-NaNO3 binary sub-molten salt
A green process for producing chromate from chromite ore has been developed in the Institute of Process Engineering, Chinese Academy of Sciences. The key of the new technology is that chromite ore is decomposed in potassium or sodium series sub-molten salt (such as KOH-H2O system) at 573K. The general reaction equation is: Cr2O3·FeO + 4NaOH/KOH+ 7/4O2 →1/2Fe2O3 + 2Na2CrO4/K2CrO4 + 2H2O . It is necessary to intensify the process, for great alkali-to-ore in potassium series sub-molten salt, and high reaction temperature in sodium series. The paper mainly focuses on the advantages of KOH-KNO3 and NaOH-NaNO3 sub-molten salt in decomposing chromite ore, and the recycle of KOH-KNO3 and NaOH-NaNO3. The ratio of KOH-to- ore reduces from 4:1 to 2:1 after adding KNO3 to KOH sub-molten salt, and the reaction temperature decreases from 803K to 623K after adding NaNO3 to NaOH sub-molten salt. As a medium, KNO3 plays a role in oxygen transfer, which obviously promotes the decomposition of the chromate ore. NaNO3 is not only a medium but also an oxidant, the synergism of NaNO3 and O2 is more effective than only O2 as oxidant. The recycle method of NaNO3 or KNO3 is similar to the method of NaOH or KOH. The residual KOH and KNO3 (or NaOH and NaNO3) are separated with the residue of chromite ore and K2CrO4 (or Na2CrO4) crystalloid, then vaporizing water are carried out. After above process, KOH and KNO3 (or NaOH and NaNO3) are reused in decomposing chromite ore.
green process chromite ore sub-molten salt KOH-KNO3 NaOH-NaNO3
YANG ZHANG SHILI ZHENG HONGBIN XU YI ZHANG
Key Laboratory of Green Process and Engineering ，Institute of Process Engineering, Chinese Academy o Key Laboratory of Green Process and Engineering ，Institute of Process Engineering, Chinese Academy o
国际会议
The 12th Asian Pacific Confederation of Chemical Engineering Congress(第十二届亚太化工联盟大会暨化工展览会)
大连
英文
2008-08-04（万方平台首次上网日期，不代表论文的发表时间）