Recent Operational Improvements of Hematite Plant …
873
Modification of Filter for De-Arsenic Process
Copper and arsenic are co-precipitated by zinc powder. The chemistry of the arsenic
removal step is shown in Eq. (1).
6Cu
2+
+ 2As
3+
+ 9Zn → 9Zn
2+
+ 2Cu 3 As
(1)
This process was introduced in 2003 to improve the quality of the hematite. A
filter press was used for separating copper arsenide residue from de-arsenic slurry.
From the start of de-arsenic process operation, copper arsenide residue had some
problems in the quality.
The one of them is the agglomeration of the residue. Photograph 6 shows normal
residue and agglomerated residue. The zinc sulfate existing in adhesion water acts
like glue when drying. Once the residue agglomerates, it causes some problems at
the next process.
Another one is residue liquefaction. Photograph 7 shows the liquefied residue.
Agglomeration
Normal
Photograph 6 Normal residue and agglomerated residue
Photograph 7 Liquefied residue
873
Modification of Filter for De-Arsenic Process
Copper and arsenic are co-precipitated by zinc powder. The chemistry of the arsenic
removal step is shown in Eq. (1).
6Cu
2+
+ 2As
3+
+ 9Zn → 9Zn
2+
+ 2Cu 3 As
(1)
This process was introduced in 2003 to improve the quality of the hematite. A
filter press was used for separating copper arsenide residue from de-arsenic slurry.
From the start of de-arsenic process operation, copper arsenide residue had some
problems in the quality.
The one of them is the agglomeration of the residue. Photograph 6 shows normal
residue and agglomerated residue. The zinc sulfate existing in adhesion water acts
like glue when drying. Once the residue agglomerates, it causes some problems at
the next process.
Another one is residue liquefaction. Photograph 7 shows the liquefied residue.
Agglomeration
Normal
Photograph 6 Normal residue and agglomerated residue
Photograph 7 Liquefied residue