Hydrometallurgical Recovery of Tin
from Harris Dross
Ryosuke Sato, Koichiro Hirata and Fumito Tanaka
Abstract Emerged businesses in recycling have been causing the accumulation of
impurities in by-processes in base metal smelters. In lead smelters, such impurities
are basically removed by drossing. Since drosses comprise several impurity elements
of approximately 20 mass% each as well as lead, they require further treatment to
separate into each element. Conventional pyrotreatments are, however, not effective
due to affinity of impurity elements at high temperatures. The authors have developed
a hydrometallurgical process to recover tin and lead separately from Harris dross
which is composed mainly of tin, arsenic, and lead. In the process developed, Harris
dross is leached to separate lead-bearing residue, then the leachate is mixed with
limestone to precipitate burtite (CaSn(OH) 6 ) selectively, and the effluent is mixed
with slaked lime to precipitate calcium arsenate. Lead-bearing residue can be recycled
to the blast furnace while burtite can be payable for tin smelters because impurities
in burtite are negligible.
Keywords Harris dross · Tin leaching · Burtite
Introduction
Hosokura Metal Mining Company (Hosokura), which is a subsidiary of Mitsubishi
Materials Corp., refines bullion by conventional Harris process in which caustic soda
and sodium nitrate are added to bullion of the temperature between 400 and 500 °C
to remove impurities as “Harris dross” [1]. After that, the dross is separated into lead
bullion and caustic copper matte by pyrotreatments since the bullion adheres to the
dross. Recovered bullion is recycled to the blast furnace and caustic matte is sent to
R. Sato (B)
Mitsubishi Materials Corporation, Kagawa, Japan
e-mail: satoryo@mmc.co.jp
K. Hirata
Mitsubishi Materials Corporation, Fukushima, Japan
F. Tanaka
Mitsubishi Materials Corporation, Tokyo, Japan
© The Minerals, Metals & Materials Society 2020
A. Siegmund et al. (eds.), PbZn 2020: 9th International Symposium
on Lead and Zinc Processing, The Minerals, Metals & Materials Series,
https://doi.org/10.1007/978-3-030-37070-1_44
519
from Harris Dross
Ryosuke Sato, Koichiro Hirata and Fumito Tanaka
Abstract Emerged businesses in recycling have been causing the accumulation of
impurities in by-processes in base metal smelters. In lead smelters, such impurities
are basically removed by drossing. Since drosses comprise several impurity elements
of approximately 20 mass% each as well as lead, they require further treatment to
separate into each element. Conventional pyrotreatments are, however, not effective
due to affinity of impurity elements at high temperatures. The authors have developed
a hydrometallurgical process to recover tin and lead separately from Harris dross
which is composed mainly of tin, arsenic, and lead. In the process developed, Harris
dross is leached to separate lead-bearing residue, then the leachate is mixed with
limestone to precipitate burtite (CaSn(OH) 6 ) selectively, and the effluent is mixed
with slaked lime to precipitate calcium arsenate. Lead-bearing residue can be recycled
to the blast furnace while burtite can be payable for tin smelters because impurities
in burtite are negligible.
Keywords Harris dross · Tin leaching · Burtite
Introduction
Hosokura Metal Mining Company (Hosokura), which is a subsidiary of Mitsubishi
Materials Corp., refines bullion by conventional Harris process in which caustic soda
and sodium nitrate are added to bullion of the temperature between 400 and 500 °C
to remove impurities as “Harris dross” [1]. After that, the dross is separated into lead
bullion and caustic copper matte by pyrotreatments since the bullion adheres to the
dross. Recovered bullion is recycled to the blast furnace and caustic matte is sent to
R. Sato (B)
Mitsubishi Materials Corporation, Kagawa, Japan
e-mail: satoryo@mmc.co.jp
K. Hirata
Mitsubishi Materials Corporation, Fukushima, Japan
F. Tanaka
Mitsubishi Materials Corporation, Tokyo, Japan
© The Minerals, Metals & Materials Society 2020
A. Siegmund et al. (eds.), PbZn 2020: 9th International Symposium
on Lead and Zinc Processing, The Minerals, Metals & Materials Series,
https://doi.org/10.1007/978-3-030-37070-1_44
519