ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Utilization of natural gypsum for the preparation of ammonium sulfate

Avanish Kumar and Swati Dubey

Department of Chemical Engineering, Marwadi University, Rajkot, India

E-mail: swati.dubey@marwadieducation.edu.in

Received: 3 August 2022  Accepted: 30 December 2022

Abstract:

Ammonium sulfate is used as a fertilizer because it supplies nitrogen and sulfur for plant nutrients. It can be obtained by three processes: as recovery from coke oven, a by-product from caprolactum and gypsum process. Natural gypsum fulfills the demands of the cement industries and is used by farmers as a direct fertilizer for reconditioning of alkaline solids for reducing alkalinity and improving crop production. The present study aims to synthesize ammonium sulfate from low-grade naturally occurring gypsum found in Rajasthan, India. Ammonium sulfate was prepared by adding a fixed amount of natural gypsum with an appropriate quantity of ammonium carbonate in distilled water at varying temperatures for different contact times in a batch reactor. The characterization of the natural gypsum and product was done by using Scanning Electron Microscopy, Energy dispersive X-ray spectroscopy, Fourier Transform Infrared, X-ray Fluorescence and X-ray Diffraction. Effect of various operating parameters including temperature (30–60 °C) and contact time (1–6 h) on product yield was studied. The maximum yield of ~ 44.7% was observed at 4 h and 50 °C. The dosage of natural gypsum was 100 gm. Design-Expert software was also applied to study the influence of both the operating parameters, and it was analyzed that maximum yield of 43.5% fit well with R² value of 0.96. Therefore, low-grade natural gypsum could be used as effective source for manufacturing ammonium sulfate.

Graphical abstract

Keywords: Ammonium sulfate; Natural gypsum; SEM; XRD; FT-IR; Design

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02660-9

Chemical Papers 77 (5) 2707–2716 (2023)