Processes for treating iron-containing waste streams
AssigneeMillennium Inorganic Chemicals, Inc.
InventorsPeter Carter, Christopher John Davis, Michael Robinson, Kirit Talati
Life of this patent
Estimating the term…
Abstract
Processes for treating iron containing waste streams are provided. According to these processes, metal-containing compounds, particularly iron oxides are produced. These methods may, for example, be used in the processing of the waste streams from the chlorination of titanium-bearing raw materials and involve the use of certain combinations of neutralization and precipitation steps.
Claims42
A process for treating iron-containing waste streams in which an iron-containing compound is produced from a liquid slurry stream, said process comprises the steps of:
- a. adding an initial neutralization agent to a liquid slurry stream to form a first precipitate and a first liquid phase, wherein said liquid slurry stream comprises iron (II) chloride;
- b. combining said first liquid phase and a sulfate-containing compound to form a second precipitate and a second liquid phase, wherein said second precipitate comprises gypsum and said second liquid phase comprises iron (II) chloride;
- c. separating said second precipitate from said second liquid phase;
- and
- d. subjecting said second liquid phase to an oxidation, neutralization and precipitation process to form an iron-containing compound and a residual liquid phase.
A process for treating iron-containing waste streams in which an iron-containing compound is produced from a liquid slurry stream, said process comprises the steps of:
- a. dividing a liquid slurry stream into a first slurry stream and a second slurry stream, wherein said liquid slurry stream comprises iron (II) chloride;
- b. adding a calcium-containing neutralization agent to said first slurry stream to form a metal hydroxide-containing precipitate and a calcium chloride-containing liquid phase;
- c. separating a majority of said calcium chloride-containing liquid phase from the metal hydroxide-containing precipitate and a minority of said calcium chloride-containing liquid phase;
- d. adding said metal hydroxide-containing precipitate and said minority of said calcium chloride-containing liquid phase to said second slurry stream to form a first precipitate and a first liquid phase;
- e. separating said first precipitate from said first liquid phase;
- and
- f. subjecting said first liquid phase to an oxidation, neutralization and precipitation process to form an iron-containing compound and a residual liquid phase.
A process for treating an iron-containing waste stream, said process comprises the steps of:
- a. adding an initial neutralization agent to a liquid slurry stream to form a first precipitate and a first liquid phase, wherein said liquid slurry stream comprises an iron (II) chloride;
- b. dividing said first liquid phase into a first solution and a second solution;
- c. adding a calcium-containing neutralization agent to said first solution to form a metal hydroxide-containing precipitate and a calcium chloride-containing liquid phase;
- d. using said metal hydroxide-containing precipitate and a minority of said calcium-chloride containing liquid phase as said initial neutralization agent;
- and
- e. subjecting said second solution to an oxidation, neutralization and precipitation process to form an iron-containing compound and a residual phase.
In the process of forming γ-FeO(OH) by precipitation, wherein the improvement comprises using sodium carbonate.
Dependencies are inferred from the claim text.