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.