Effect of Lime on Stability of Chromium in Stainless Steel Slag

The stabilization of chromium is of great importance to the use of stainless steel slag (SSS), and the influence of lime on the stability of chromium is currently unclear. In this work, the variation of phase transformation and chromium distribution with slag basicity (CaO/SiO2) were investigated experimentally, and the leaching ability of chromium was evaluated. Results showed that chromium-bearing phases were glass, dicalcium silicate (C2S), spinel, and periclase, while the degree of enrichment of chromium in these phases was found to be closely related to the basicity. The optimal basicity obtained in this research was 1.5, with the chromium mainly present in the stable spinel and exhibiting the lowest leaching ability. The product layer structure of unmelted lime was studied as well, showing a periclase layer and a Ca2SiO4 layer. Some CaCr2O4 had formed in the periclase layer, which is potentially hazardous for the environment and living organisms.

[1]  Qing-jie Zhao,et al.  Decomposition mechanism of chromite in sulfuric acid–dichromic acid solution , 2017, International Journal of Minerals, Metallurgy, and Materials.

[2]  C. Kan,et al.  Hexavalent chromium removal from aqueous solution by adsorbents synthesized from groundwater treatment residuals , 2017 .

[3]  T. Jiang,et al.  Effects of Basicity and MgO in Slag on the Behaviors of Smelting Vanadium Titanomagnetite in the Direct Reduction-Electric Furnace Process , 2016 .

[4]  L. Teng,et al.  Effect of basicity on chromium partition in CaO–MgO–SiO2–Cr2O3 synthetic slag at 1873 K , 2014 .

[5]  S. Millman,et al.  Dissolution of lime in BOS slag: from laboratory experiment to industrial converter , 2014 .

[6]  A. Romero-Serrano,et al.  Effect of MgO and CaO/SiO2 on the immobilization of chromium in synthetic slags , 2012 .

[7]  T. Miki,et al.  Prevention of Chromium Elution from Stainless Steel Slag into Seawater , 2011 .

[8]  M. Barati,et al.  Effect of slag basicity and oxygen potential on the distribution of boron and phosphorus between slag and silicon , 2011 .

[9]  S. Seetharaman,et al.  Experimental Studies on the Oxidation States of Chromium Oxides in Slag Systems , 2010 .

[10]  Bo Björkman,et al.  Crystallization Behaviour of some Steelmaking Slags , 2010 .

[11]  D. Sichen,et al.  Dissolution of Lime in Synthetic ‘FeO’‐SiO2 and CaO‐‘FeO’‐SiO2 Slags , 2010 .

[12]  S. Jahanshahi,et al.  Effect of Slag Basicity on Phase Equilibria and Selenium and Tellurium Distribution in Magnesia-Saturated Calcium Iron Silicate Slags , 2010 .

[13]  P. Drissen,et al.  Recent Development in Slag Treatment and Dust Recycling , 2009 .

[14]  H. Matsuura,et al.  Condensation of P2O5 at the Interface between 2CaO·SiO2 and CaO–SiO2–FeOx–P2O5 Slag , 2009 .

[15]  A. Romero-Serrano,et al.  Immobilization of Chromium in Slags using MgO and Al2O3 , 2008 .

[16]  A. Cruz-Ramírez,et al.  Estabilización de la espinela MgCr 2 O 4 en escorias del sistema SiO 2 -CaO-MgO-Cr 2 O 3 , 2006 .

[17]  F. Tsukihashi,et al.  Reaction Mechanism between Solid CaO and FeOx–CaO–SiO2–P2O5 Slag at 1 573 K , 2006 .

[18]  R. Inoue,et al.  Behavior of Phosphorous Transfer from CaO–FetO–P2O5(–SiO2) Slag to CaO Particles , 2006 .

[19]  Kazuki Morita,et al.  Activity of Chromium Oxide in CaO‐SiO2 based Slags at 1873 K , 2005 .

[20]  H. von Blottnitz,et al.  Ageing of chromium(III)-bearing slag and its relation to the atmospheric oxidation of solid chromium(III)-oxide in the presence of calcium oxide. , 2003, Chemosphere.

[21]  A. Muan,et al.  Oxidation State of Chromium in CaO–Al2O3–CrOx–SiO2 Melts under Strongly Reducing Conditions at 1500°C , 1992 .

[22]  A. Muan,et al.  Activity–Composition Relations of Chromium Oxide in Silicate Melts at 1500°C under Strongly Reducing Conditions , 1992 .

[23]  Dhanpat Rai,et al.  Chromium(III) hydrolysis constants and solubility of chromium(III) hydroxide , 1987 .

[24]  Xingrong Wu,et al.  Crystallization Behaviour of Chromium in Stainless Steel Slag: Effect of Feo and Basicity , 2016 .

[25]  J. Burja,et al.  CHROMITE SPINEL FORMATION IN STEELMAKING SLAGS NASTANEK KROMITNIH SPINELOV V JEKLARSKIH @LINDRAH , 2014 .

[26]  P. Jönsson,et al.  Influence of slag properties on the amount of solid precipitates in high-chromium EAF steelmaking , 2011 .

[27]  A. Alper,et al.  Phase Equilibria in the System MgO—MgCr2O4 , 1964 .