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The On-Stream X-ray Diffraction Analyses of Phosphate Rock Slurries at the IMC-Agrico Four Corners Plant



A system for the on-stream X-ray diffractometric determination of mineral phases in slurries was developed at Mintek. A contractual agreement between the Florida Institute of Phosphate Research (FIPR) and IMC Agrico (contract #93-04-051R) was signed in July 1993, whereby IMC Agrico was appointed as the contractor for the project, with Mintek acting as a subcontractor. The principal goal of this project was to demonstrate the capabilities and benefits of on-stream X-ray diffraction (Midfox), at a beneficiation plant to the Florida phosphate industry.

In preparation for the installation of the equipment at the Four Corners mine, hardware components such as the slurry transporting system, as well as customized software to control the analyser and process the data, were developed at Mintek. The system was installed at the Four Comers plant in July and August, 1994. From then onwards until the end of October, the quartz and Bone Phosphate of Lime (BPL) concentrations of sample sets of rougher tails, amine feeds and final concentrates were measured. The results of 163 calibration samples as well as 584 further analyses are presented in this report.

The range in plant product compositions encountered during the sampling campaign exceed Midfox measuring errors in all instances.

Range of concentrations, rougher tails is 91.1 – 98.0 quartz (insolubles) [BPL, 0.4-3.5]; Midfox error is 0.7 quartz (insolubles) [BPL, 0.4]

Range of concentrations, amine feeds is 10.3 – 44.00 quartz (insolubles) [BPL, 40.2 – 64.6]; Midfox error is 1.7 quartz (insolubles) [BPL, 2.4]

Range of concentrations, final concentrates is 3.3 – 16.8 quartz (insolubles) [BPL, 59.8 – 72.2]; Midfox error is 1.0 quartz (insolubles) [BPL, 2.4]

This shows that fluctuations on the plant product compositions can be quantitatively monitored by the Midfox system.

The benefits of the Midfox on-stream analyser to the phosphate industry are discussed.