The production of phosphoric acid for fertilizer is expensive, make impure acid, and has a large enviromental footprint. This phase I program involves a laboratory program to determine basic chemical and physical data to assess the viability of a process called the KPA process, to produce phosphoric acid (now a ten billion dollar market) for manufacturing fertilizer and detergents. The new process is projected from demonstration tests and preliminary engineering studies to produce phosphoric acid at much higher purity, at substantially lower cost, and with a significantly smaller environmental footprint. It may also allow processing of ores not suitable in the current wet phosphoric acid processes OBJECTIVES: The objective of the Phase I research program, is to determine in detail the rate of phosphorus extraction from a phosphate ore/coke mixture, under a temperature profile it would encounter in a rotary kiln, and to determine the reaction products and melting behavior of the kiln burden throughout the kiln passage. The ore formulation is chosen based on extensive previous experience and theoretical analysis, but may include some optimization during the test work. This objective will include screening various phosphate ore/silica/carbon particle size effects on the rate of reaction, various carbon sources including petroleum coke and various coals, and the effect of various major potential impurities including magnesium, sodium and potassium on the effect on melting in the kiln burden. A second major objective is to construct a process engineering package for a commercial plant using the KPA technology, and to calculate an order-of-magnitude cost estimate for the process. A final report will also include a preliminary analysis of product quality and environmental footprint comparisons with the conventional sulfuric acid based processes. APPROACH: The research program will involve experiments in which the phosphate ore/silica/coke mixtures are heated in thermo analysis equipment, which allows the continuous weighing, and quantification of heat absorption/ release from the sample. The composition of the ore is selected based on a new theoretical determination made by the principal investigator of this proposal, which was partially validated by a program conducted by Occidental Petroleum Corporation nearly twenty-five years ago. This so called TGA-DTA analysis allows the determination of: 1) what temperature the phosphorus extraction occurs by observing the associated weight loss and heat absorption and 2) when melting occurs by observing the associated heat absorption. This data will show the size of the window of operation for rotary kiln processing. The same equipment can be used to see how fast the reaction proceeds with various particle sizes of raw material grinds and different temperatures, thereby setting one of the constraints of the grinding requirements, and the size of the rotary kiln required for the commercial process. Chemical, XRD, and microprobe analysis will clarify the details of the reactions of the major and minor components in the process. A process flow sheet and heat and material balance for the process will be constructed from the lab data supported by thermodynamic data. From this analysis, the experts involved in this program will design and select equipment suitable for the process, which may require assumptions where data is still lacking, and determine the size and outline specifications for the equipment. This will allow an order- of- magnitude cost estimate to be made for the process. Phase I of the program is expected to show whether the process is likely to be achievable in commercial equipment, and if so an idea of how much it will cost
