Method for removing chrome and/or nickel from liquid slags
AssigneeHolcim Ltd.
InventorAlfred Edlinger
Life of this patent
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Abstract
In a method for removing chromium oxide and nickel oxide, and combinations thereof, from liquid slags or slag mixtures, in which the liquid slag is A charged onto a metal bath, in particular an iron bath, and reduced by feeding carbon or carbon carriers, the carbon feed into the metal bath is effected until a decrease of the Cr and/or Ni oxide contents of the slag to a value of between 0.8 wt.-% and 0.2 wt.-%. As the pregiven Cr and/or Ni oxide content range of the slag is reached, reductants having higher reduction potentials such as, e.g., Al, Ca, Si, Fe—Si or Ca—Si are added in order to lower the Cr and/or Ni oxide contents to below 0.15 wt.-%, preferably below 0.08 wt.-%.
Claims12
A method for removing chromium oxide and nickel oxide, and combinations thereof, from liquid slag, comprising the steps:
- charging liquid slag onto a metal bath;
- reducing said liquid slag by feeding at least one of the group consisting of carbon and carbon carriers into the metal bath, until the combined chromium oxide and nickel oxide content of the liquid slag has decreased to between O2 and 0.8 percent by weight;
- and
- further reducing said liquid slag by adding at least one reductant having a higher reduction potential to further decrease the combined chromium oxide and nickel oxide content of the liquid slag to below 0.15 percent by weight.
Dependencies are inferred from the claim text.