The preparation method of ferrous sulfate heptahydrate

Introduction

Ferrous sulfate heptahydrate An iron salt, produced as a natural by-product of the titanium dioxide (TiO2) manufacturing process, and subsequently used to produce animal feeds, cement, pigments, and in biogas and water treatment applications[1].

Typical appearance of ferrous sulfate heptahydrate is green or bluish-green solid Ferrous sulfate heptahydrate has many applications, such as quantitative analysis of nitrates. Ferrous sulfate heptahydrate, forms monohydrate at 65 °C. Aqueous solubility is 48.6 g in 100 mL at 50 °C。Due to inherent oxidation, ferric ion (Fe3+) content may increase on storage.

Picture 1 Ferrous sulfate heptahydrate powders

The toxicity of ferrous sulfate heptahydrate

A 2.5% mortality rate was observed in a flock of 19,000 commercial one-day-old broiler chicks that had been placed 24 hours previously on litter treated with ferrous sulfate heptahydrate[2]. Ulcerative ventriculitis and severe hepatopathy were the primary lesions observed grossly and microscopically. Pooled digesta contained 6854 ppm iron. Lesions identical to those found in the field case were reproduced experimentally.

Method of producing ferrous sulfate heptahydrate

In a method of producing ferrous sulfate heptahydrate, ferrous sulfate monohydrate is converted in a crystallization reactor in the presence of water into ferrous sulfate heptahydrate as crystallized product, and water is subsequently isolated from the ferrous sulfate heptahydrate[3]. Ferrous sulfate monohydrate is obtained from a pickling solution containing ferrous chloride, hydrochloric acid and water and reacted in a precipitating reactor in the presence of excess sulfuric acid to form ferrous sulfate monohydrate and hydrochloric acid. The ferrous sulfate monohydrate is then dehumidified and converted in a crystallization reactor in the presence of excess water into ferrous sulfate heptahydrate.

Method of purifying ferrous sulfate heptahydrate

  Ferrous sulfate heptahydrate is purified by adding crude ferrous sulfate heptahydrate and ferrous sulfate heptahydrate crystal mother liquor, and heating to 50-90 degrees C with stirring to form saturated ferrous sulfate solution; keeping temperature of saturated ferrous sulfate solution at 50-90 degrees C, then adding ferrous carbonate, adjusting pH value of solution to 3.5-4.5, allowing release of carbon dioxide, hydrolyzing to precipitate impurity, centrifuging and separating to obtain high purity ferrous sulfate solution; and crystallizing separated filtrate at 5-20 degrees C[4].

Application of ferrous sulfate heptahydrate in chromite ore processing residue

A pugmill treatability study was conducted to remediate chromite ore processing residue (COPR) using ferrous sulfate heptahydrate as a reductant. Ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) was employed to reduce hexavalent chromium in two dosages with soil mixing equipment. Industrial ferrous-sulfate heptahydrate was used as iron salt for the synthesis of ferrates. Ferrous sulfate heptahydrate was selected as the ferrous ion source[4].

Application of ferrous sulfate heptahydrate in Synthesis of Fe3O4 MNPs

0.2780 g of the FeSO4·7H2O was dissolved in 5 mL of EG to form a homogeneous solution. Then, the controlled amount of KOH solution (0.5 M, 1 M 1.5 M or 5 M) was added to the prepared iron salt solution at room temperature under stirring[5]. The mixture stirring was continued to get a homogeneous solution. The resultant homogeneous mixture solution was then transferred to a 30 mL Teflon lined stainless steel autoclave, was sealed and maintained at 200 °C for 24 h. After the completion of the reaction, the black solid products were collected by magnetic separation and washed with ethanol three times. The final products were dried in a vacuum oven at 40 °C for 6 h.

Reference

1 KEHRMANN ALEXANDER [DE]. EP1609760A1;US2005281732A1;US7097816B2

2 TIANJIN OUKE NEW MATERIAL CO LTD. CN111952061-A

3 Wallner-Pendleton E, Froman D P, Hedstrom O. Identification of ferrous sulfate toxicity in a commercial broiler flock[J]. Avian diseases, 1986: 430-432.

4 Adapting a Model for Literacy Learning to the Learning of Mathematics / Reading & Writing Quarterly Hopkins, 2007

5 Zhang X, Liu Z, Fan X, et al. Optimization of reaction conditions for the electroleaching of manganese from low-grade pyrolusite[J]. International Journal of Minerals, Metallurgy, and Materials, 2015, 22(11): 1121-1130.

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