Low-grade calcareous phosphate rocks with high carbonate content are common in various regions. Researchers compared two methods, calcination and leaching, to improve the quality of these rocks for fertilizer production. They found that calcination is more effective in reducing calcium carbonate levels in the ore compared to leaching. Optimal conditions for calcination resulted in a phosphate concentrate with low loss on ignition and high weight recovery. Leaching with acetic acid also improved the phosphate content of the ore, but not as efficiently as calcination. Overall, the study concluded that calcination is a better method for enhancing low-grade calcareous phosphate ore quality.