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Recycling of Ferrous Sulfate by the Synthesis of a New Super Oxidant Material

Objective



Syntheses of new high value added materials and the recycling of industrial wastes are challenges to be met by the EU's chemical enterprises to keep their market share in the global economy. This proposal responds to theses challenges. It suggests the use of ferrous sulfate for the production of sodium ferrate. The EU's countries produce about 1.5 million tons/ year of ferrous sulfate as a by product of the titanium and the surface treatment industries (ICI, SOLLAC, ARBED, KEMIRA, etc.). It is a cheap, largely available and partly valorized by product. On the other hand, potassium ferrate (K2FeO4) is a super oxidant that reacts with water and generates nascent oxygen and hydroxide groups as illustrated by the following equation:

4 K2FeO4 + 10 H2O < 4 Fe(OH)3 + 8 K+ + 8 OH + 3O2

Producing nascent O2 and generating hydroxide groups allow K2FeO4 to be used for many applications such as: water treatment, effluents' decontamination, cyanide and organic materials' destruction, decolorization of textile dyes' effluents, phosphates' elimination, soil remediation, etc. The use of potassium ferrate in water treatment will replace the bactericide agents (Cl2 and ClO2), the coagulant flocculant agents [FeCl3 and Al2(SO4)3] and the lime used for precipitating heavy metal ions. Moreover, the use of ferrate will eliminate the halo organic compounds suspected to be cancerogenic substances and the aluminum ions supposed to favor Alzheimer's disease. However, the cost of potassium ferrate synthesis is relatively high and its stability is poor. To avoid these
disadvantages, a partner of this consortium had succeeded the dry synthesis of K2FeO4 at 20 C using Fe(OH)3, Ca(OCl)2 and KOH. To our knowledge, it is the first time that such a synthesis of K2FeO4 was successful. The process was patented (EU 89402241/7 and WO 91/07352). Moreover, this team was able to extend the stability of K2FeO4 to 6 months by partial substitution of Fe by S [K2(Fe0.5S0.5)O4].
The objective of this project is to optimize and to decrease the dry synthesis costs of the ferrate salts on the laboratory scale. This can be achieved by using Na salts instead of K ones, Cl2 gas instead of Ca(OCl)2, industrial FeSO4 instead of pure reagent, etc. This will be followed by a large scale experimentation to produce several kilograms necessary for the industrial partners to test the efficiency and the stability of this compound. The success of this project will be a breakthrough in the water treatment and effluent decontamination sectors regarding the water quality and the public health. As this consortium is composed of a ferrous sulfate provider,
multidisciplinary research teams and a major chemical company as manufacturer and end user, it is thought that the research results' transfer will take only 3 to 4 years because the market needs are important.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITE HENRI POINCARE NANCY 1
Address
Boulevard Des Aiguillettes
54506 Vandoeuvre-les-nancy
France

Participants (5)

FUNDACION INASMET - ASOCIACION DE INVESTIGATION METALURGICA DEL PAIS VASCO
Spain
Address
12,Mikeletegi Pasealekua, 2
20009 San Sebastian
GENT UNIVERSITY
Belgium
Address
653,Coupure Links 653
9000 Gent
INSTITUT NATIONAL POLYTECHNIQUE DE LORRAINE
France
Address
Rue Du Doyen M. Roubault
54501 Vandoeuvre-les-nancy
Lavaux Assainissement SA
Luxembourg
Address
Route De La Sauvage
4829 Rodange
Solvay S.A.
France
Address
1,1 Rue G. Peri
54110 Dombasle-sur-meurthe