Iranian Researchers Extract Silver, Lead from Industrial Waste

Hossein Kamran Haqiqi was the researcher of this project, which was carried out by using the flotation process to extract lead and silver, along with acid leaching to recover zinc.

One of the results of this project was the production of lead concentrate with a grade of 100% and silver of 800 ppm, and the production of zinc concentrate with a grade of 18%.

The industrial wastes abandoned in Zanjan contained valuable metals, but low in grade, and their extraction was not cost-effective until now; therefore, such a project was implemented with the innovation of combining flotation and acid leaching as an environmentally-friendly and low-cost method.

Determining the standard and tonnage zones in the 7-million-ton depot, using conventional chemicals to reduce costs, and designing the initial plant with a return on investment of 2.22 years are the next steps in the project.

This project is a successful model of university-industry collaboration to resolve the environmental problems and create added value from seemingly worthless resources.

In a relevant development in April, Iranian researchers at the Faculty of Environment of the University of Tehran had also succeeded in producing a type of fertilizer from industrial waste suitable for Iran's calcareous soils.

“The idea of ​​producing iron-ligand fertilizer from industrial waste was formed by implementing projects supported by the National Elite Foundation. The goal of this project is to optimally use domestic industrial waste and produce effective fertilizer for the special conditions of Iran's calcareous soils,” said Zahra Qeshlaqi, a faculty member of the Faculty of Environment of the University of Tehran and the head of the research team.

“Biotechnological studies on plants resistant to iron deficiency in calcareous soils and the identification of key compounds that initiate enzymatic reactions in plants provided the scientific basis for this project. The research led to the design of a fertilizer formulation that, with a high percentage of soluble iron and high absorption capacity, provides a practical response to the challenge of iron deficiency in agriculture,” she added.

Noting that iron-ligand fertilizer is produced using advanced chemical and biotechnological technologies and using domestic industrial waste and has outstanding characteristics, Qeshlaqi said, “Among other things, this fertilizer uses hydroxypyridinone compounds that form a stable bond with iron, increasing its absorption capacity in a wide range of soil pH conditions. In addition, a special coating in the formulation of this fertilizer provides the most optimal pH conditions and oxidation-reduction potential and improves iron absorption. Finally, the raw materials for the production of this fertilizer include iron chips, steel slag and mine waste, which are recycled and converted into soluble iron powder using advanced techniques.”

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