"FIPR is a worldwide phosphate intellectual powerhouse. It gathers knowledge from scientists and researchers in the United States and around the world to address issues and topics related to Florida phosphate. Since its inception in 1978, FIPR has facilitated technical innovations to make phosphate mining and processing operations more efficient. The institute has successfully sponsored numerous research projects and conferences regarding phosphate beneficiation. One of FIPR's high priorities in recent years is to develop a viable technology to process high dolomite pebble. This is an important research effort as the phosphate industry faces the challenge of treating dolomite impurities in Florida phosphate reserves. Pilot studies connected to one FIPR research project have demonstrated a new process to economically process high dolomite pebble. This new technology could allow the industry to utilize Florida reserves more effectively and to reduce the costs for permitting and reclamation."

Dr. Chaucer Hwang
Chief Engineer - Technology Development
IMC Phosphates Company

Phosphate Quality is declining as mining moves south of the traditional Bone Valley mining area. The cause: dolomite, a magnesium containing mineral, which is found in high quantities in the ore being mined to the south than elsewhere. A major topic of research is what can be done to separate the dolomite from the rock because dolomite causes problems in the phosphate chemical processing plant. The phosphate deposits in what is known as the Southern Extension may be divided into two zones: an upper zone and a lower zone. The upper zone can be processed with existing technology. The ore in the lower zone has a lot of dolomite (magnesium) and is mostly not mined. If the dolomite could be separated from the phosphate economically, Florida could substantially increase the amount of phosphate that is mined.

A FIPR project, "Development of New Beneficiation Technology for Florida Dolomitic Phosphate," has developed a viable process for the dolomitic phosphate resources in Florida. This process is known as the CLDRI process because the major subcontractor for the laboratory development of the process flowsheet for high-dolomitic pebbles in Florida was the Chinese Lianyungang Design Research Institute (CLDRI). CLDRI is perhaps the only organization in the world to have implemented flotation technology to deal with the problem of dolomite on a commercial scale.

The CLDRI process developed for Florida first washes the pebbles to remove the clay, then grinds the pebbles to suitable size particles for liberating the dolomite and other impurities from the phosphate. The ground slurry is then floated with a proprietary reagant that collects the dolomite and allows the phosphate to sink away from it. The phosphate product is then floated again to remove the sand. This research also confirmed that the proprietary reagant can be economically reproduced using materials in the United States for use in Florida.

Jacobs Engineering has done a preliminary economic analysis of the work and estimates the total costs for the CLDRI flotation process to be about $15.60 per ton of final product, which is a few dollars less than that for processing low-dolomitic deposits in current Florida operations. The study was based on a plant capacity of 300 tph (tons per hour) of pebble containing 54% BPL and 2% MgO and 200 tph concentrate containing 66% BPL and 0.82% MgO. The study also estimated the construction of the battery limits beneficiation plant to be $32 million dollars.

Another FIPR-sponsored project has developed a reliable instantaneous method to analyze the amount of dolomite in phosphate as it moves out of the beneficiation plant. The method, which uses laser-induced breakdown spectroscopy (LIBS), analyzes wet mineral samples on a moving conveyor belt. FIPR has filed for patent protection on this novel process that may increase the amount of phosphate that can be recovered in the beneficiation of the dolomitic rock.

This project resulted from interest generated in a presentation on laser-induced fluorescence given at the 1998 International Beneficiation Conference that FIPR co-hosted with the Engineering Foundation.

Such instantaneous analysis could provide an economically viable method for real-time evaluation of dolomite contents in phosphate rocks in order to remove dolomite prior to beneficiation.

The FIPR Board of Directors has approved further funding for developing a prototype on-line LIBS analyzer for phosphate pebbles based on the method developed under the first project.