Recycling of waste pickle acid by precipitation of metal fluoride hydrates

Kerstin M. Forsberg; Åke C. Rasmuson

doi:10.1016/j.mineng.2007.03.011

Recycling of waste pickle acid by precipitation of metal fluoride hydrates

Kerstin M. Forsberg
, Åke C. Rasmuson

KTH Royal Institute of Technology

Research output: Contribution to journal › Article › peer-review

Abstract

Stainless steel is pickled in mixed acid solutions (1-3 M HNO₃ and 0.5-4 M HF). The spent solution is usually neutralized with lime, and in Sweden about 18,000 tons/yr of metal hydroxide sludge is disposed as landfill waste. We are developing a cost-saving and environmentally friendly process, involving crystallization of β-FeF₃ · 3H₂O, where the metal content is recovered and the acid is recycled. Iron has been successfully separated from spent pickle bath solutions by precipitation of β-FeF₃ · 3H₂O in a continuous crystallizer (10 L scale) where the solution is concentrated by nanofiltration. The crystal growth rate of β-FeF₃ · 3H₂O has been determined in industrial pickle bath solutions at 50 °C and the results have been compared to previous measurements in pure HF/HNO₃ solutions prepared in the laboratory. The growth rate of β-FeF₃ · 3H₂O crystals at 50 °C is in the order of 10^-11 m/s in both industrial and pure acid mixtures.

Original language	English
Pages (from-to)	950-955
Number of pages	6
Journal	Minerals Engineering
Volume	20
Issue number	9 SPEC. ISS.
DOIs	https://doi.org/10.1016/j.mineng.2007.03.011
Publication status	Published - Aug 2007
Externally published	Yes

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 12 Responsible Consumption and Production

Keywords

Hydrometallurgy
Recycling
Waste processing

Access to Document

10.1016/j.mineng.2007.03.011

Cite this

@article{d0b50ba5de7741cb9ef6e44dcd72763b,

title = "Recycling of waste pickle acid by precipitation of metal fluoride hydrates",

abstract = "Stainless steel is pickled in mixed acid solutions (1-3 M HNO3 and 0.5-4 M HF). The spent solution is usually neutralized with lime, and in Sweden about 18,000 tons/yr of metal hydroxide sludge is disposed as landfill waste. We are developing a cost-saving and environmentally friendly process, involving crystallization of β-FeF3 · 3H2O, where the metal content is recovered and the acid is recycled. Iron has been successfully separated from spent pickle bath solutions by precipitation of β-FeF3 · 3H2O in a continuous crystallizer (10 L scale) where the solution is concentrated by nanofiltration. The crystal growth rate of β-FeF3 · 3H2O has been determined in industrial pickle bath solutions at 50 °C and the results have been compared to previous measurements in pure HF/HNO3 solutions prepared in the laboratory. The growth rate of β-FeF3 · 3H2O crystals at 50 °C is in the order of 10-11 m/s in both industrial and pure acid mixtures.",

keywords = "Hydrometallurgy, Recycling, Waste processing",

author = "Forsberg, \{Kerstin M.\} and Rasmuson, \{{\AA}ke C.\}",

year = "2007",

month = aug,

doi = "10.1016/j.mineng.2007.03.011",

language = "English",

volume = "20",

pages = "950--955",

journal = "Minerals Engineering",

issn = "0892-6875",

number = "9 SPEC. ISS.",

}

TY - JOUR

T1 - Recycling of waste pickle acid by precipitation of metal fluoride hydrates

AU - Forsberg, Kerstin M.

AU - Rasmuson, Åke C.

PY - 2007/8

Y1 - 2007/8

N2 - Stainless steel is pickled in mixed acid solutions (1-3 M HNO3 and 0.5-4 M HF). The spent solution is usually neutralized with lime, and in Sweden about 18,000 tons/yr of metal hydroxide sludge is disposed as landfill waste. We are developing a cost-saving and environmentally friendly process, involving crystallization of β-FeF3 · 3H2O, where the metal content is recovered and the acid is recycled. Iron has been successfully separated from spent pickle bath solutions by precipitation of β-FeF3 · 3H2O in a continuous crystallizer (10 L scale) where the solution is concentrated by nanofiltration. The crystal growth rate of β-FeF3 · 3H2O has been determined in industrial pickle bath solutions at 50 °C and the results have been compared to previous measurements in pure HF/HNO3 solutions prepared in the laboratory. The growth rate of β-FeF3 · 3H2O crystals at 50 °C is in the order of 10-11 m/s in both industrial and pure acid mixtures.

AB - Stainless steel is pickled in mixed acid solutions (1-3 M HNO3 and 0.5-4 M HF). The spent solution is usually neutralized with lime, and in Sweden about 18,000 tons/yr of metal hydroxide sludge is disposed as landfill waste. We are developing a cost-saving and environmentally friendly process, involving crystallization of β-FeF3 · 3H2O, where the metal content is recovered and the acid is recycled. Iron has been successfully separated from spent pickle bath solutions by precipitation of β-FeF3 · 3H2O in a continuous crystallizer (10 L scale) where the solution is concentrated by nanofiltration. The crystal growth rate of β-FeF3 · 3H2O has been determined in industrial pickle bath solutions at 50 °C and the results have been compared to previous measurements in pure HF/HNO3 solutions prepared in the laboratory. The growth rate of β-FeF3 · 3H2O crystals at 50 °C is in the order of 10-11 m/s in both industrial and pure acid mixtures.

KW - Hydrometallurgy

KW - Recycling

KW - Waste processing

UR - https://www.scopus.com/pages/publications/34447256127

U2 - 10.1016/j.mineng.2007.03.011

DO - 10.1016/j.mineng.2007.03.011

M3 - Article

AN - SCOPUS:34447256127

SN - 0892-6875

VL - 20

SP - 950

EP - 955

JO - Minerals Engineering

JF - Minerals Engineering

IS - 9 SPEC. ISS.

ER -

Recycling of waste pickle acid by precipitation of metal fluoride hydrates

Abstract

UN SDGs

Keywords

Access to Document

Other files and links

Fingerprint

Cite this