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In response to the directive of Vietnam National Chemical Group under Official Letter No. 1953/HCVN-KT dated 4th September 2026 on proposing and implementing scientific and technological tasks, DAP No 2 – Vinachem Joint Stock Company has coordinated with the Vietnam Institute of Industrial Chemistry and Chinese experts to discuss research avenues for producing sulphuric acid (H₂SO₄) from phosphogypsum (PG), a by-product generated in DAP production.

Exploring Uses for Phosphogypsum

During DAP production, large volumes of phosphogypsum (PG) are generated. PG consists mainly of calcium sulphate (CaSO₄.2H₂O), along with other components. Researching solutions to process and reuse PG aims to add value to this by-product and reduce storage pressures.

In response, DAP No 2 – Vinachem organised a working session with the Vietnam Institute of Industrial Chemistry and Donghua Company (CNCEC), along with Chinese experts, to discuss research into producing H₂SO₄ from PG.

Attending the session were the General Director, Deputy General Directors, and technical staff from DAP No 2 – Vinachem; the Director and technical specialists from the Vietnam Institute of Industrial Chemistry; and Mr. Jaden Liang, Commercial Director, together with Chinese experts from Donghua (CNCEC).

The discussions focused on the characteristics of PG, the potential to recover and convert valuable components, possible technological approaches, and the necessary conditions for research and trials.

From PG to Sulphuric Acid

In principle, PG contains calcium sulphate and can be investigated for sulphur recovery to produce sulphuric acid. The process involves converting sulphur-containing compounds into SO₂, then oxidising SO₂ to SO₃ and absorbing it to form H₂SO₄.

This is the general principle for the research direction. The detailed technology, operating conditions, and applicability to PG generated during DAP production require further study, trials, and evaluation.

Aspects to be considered include raw material characteristics, sulphur recovery potential, process efficiency, product quality, equipment and energy requirements, treatment of by-product streams, and economic viability.

If technical and economic requirements are met, this research could provide an additional solution for using PG, enhancing the value of by-products from DAP production.

Ongoing Assessment of Application Potential

With strengths in research, development, and technology transfer in the chemical sector, the Vietnam Institute of Industrial Chemistry will continue to analyse PG characteristics and evaluate suitable technological options with relevant units.

Based on research and trial outcomes, the parties will consider the technical, economic, and environmental feasibility of the solution and propose suitable ways forward.

Research into producing H₂SO₄ from PG offers a potential solution for the effective use of by-products in DAP production, aligning with the focus on enhanced scientific research, technological innovation, and the development of circular production solutions in the chemical industry.

This working session provides a foundation for DAP No 2 – Vinachem, the Vietnam Institute of Industrial Chemistry, and experts to continue joint research, technology evaluation, and the design of scientific and technological tasks in the coming period.