Process Economics Program Report No. 8C WET PROCESS PHOSPHORIC ACID (August, 1982) Abstract Three processes to produce wet process phosphoric acid are evaluated. The dihydrate process, once the undisputed leader, is now, as a result of rising energy and raw material prices, no more economic than hemihydrate and hemihydrate-dihydrate processes. The optimum choice is likely to depend on the specific location, energy costs, type of rock, and end product application. The upgrading of wet process phosphoric acid to commercial grade phosphoric acid by solvent extraction appears economical relative to producing the latter grade in new facilities for furnace acid. Rowever, because of the depressed state of the electric furnace phosphorus industry, new commercial grade phosphoric acid capacity will probably not be required before the mid 1980s. Uranium extraction from wet process phosphoric acid, which was potentially a profitable adjunct to wet process phosphoric acid plant OperatiOnS in 1978 at a U308 price of $45/lb, is now economically borderline at a U308 price of $24-$28/1b. Adaptation of the extraction process to recover more than one metal, or its integration with wet process acid upgrading operations, may help to improve overall profitability. PEP'80 CEH
Report No. 8C WET PROCESS PHOSPHORIC ACID SUPPLEMENT C by GEORGE E. HADDELAND a I Cl I 693 A private report by the August 1982 PROCESS ECONOMICS PROGRAM Menlo Park, California 94025
For detailed marketing data and information, the reader is referred to one of the SRI programs specializing in marketing research. The CHEMICAL ECONOMICS HANDBOOK Program covers most major chemicals and chemical products produced in the United States and the WORLD PETROCHEMICALS Program covers major hydrocarbons and their derivatives on a worldwide basis. In addition, the SRI DIRECTORY OF CHEMICAL PRODUCERS services provide detailed lists of chemical producers by company, product, and plant for the United States and Western Europe. ii
CONTENTS 1 INTRODUCTION......................... 1 2 SUMMARY........................... 3 Production, Prices, and Raw Materials... Phosphoric Acid Processes... Technology... Economics... Purification of Wet Process Phosphoric Acid to Industrial Grade... Technology... Economics... Uranium Recovery from Wet Process Phosphoric Technology... Economics...... 3... 4... 4... 5... 7... 7 0 Acid... 1;... 10... 11 3 INDUSTRY STATUS... 15 Phosphoric Acid Production... 15 Phosphoric Acid Price... 19 Raw Material Prices... 19 Sulfur... 19 Phosphate Rock... 27 Declining Quality of Florida Rock... 29 4 PROCESS CHEMISTRY AND ENERGY... 31 Phosphate Rock Dissolution... 31 Liquid Membrane Process for Uranium Extraction... 33 Energy Conservation in Wet Process Phosphoric Acid Manufacture... 34 5 WET PROCESS PHOSPHORIC ACID... 37 Recent Developments... 39 Dihydrate Processes... 39 Hemihydrate/Dihydrate Processes... 42 Hemihydrate Processes... 50 Dihydrate Process... 60 Process Description... 60 Process Discussion... 64 Cost Estimates... 64 iii
CONTENTS 5 WET PROCESS PHOSPHORIC ACID (continued) Hemihydrate/Dihydrate Process... Process Description... Process Discussion... 77 Cost Estimates... 78 Hemihydrate Process... 86 Process Description... 86 Process Discussion... 90 Cost Estimates... 90 Discussion of Wet Process Phosphoric Acid Costs... 98 Conclusion... 100 6 PHOSPHORIC ACID PURIFICATION... 103 Purification Technology... 104 Methods... 104 Chemical and Physical Methods... 119 Process Description... 128 Process Discussion... 133 Cost Estimates... 133 Capital Costs... 133 Production Costs... 134 Discussion of Costs... 135 7 RECOVERY OF URANIUM FROM WET PROCESS PHOSPHORIC ACID... 145 Technology... 146 Patents...'... ;... 152 Process Description... 160 Process Discussion... 165 Cost Estimates... 166 Capital Costs... 166 Production Costs... 166 Discussion of Costs... 167 8 RECOVERY OF OTHER METALS FROM PHOSPHATE ROCK... 175 Vanadium... 177 Rare Earths... 178 Conclusions... ;... 178 iv
CONTENTS APPENDIX A DESIGN AND COST BASIS.............. 179 APPENDIX B PHYSICAL AND THERMAL DATA............ 183 APPENDIX C ANALYSIS AND SPECIFICATIONS... 187 APPENDIX D CORROSION, WASTE DISPOSAL, AND POLLUTION CONTROL... 189 CITED REFERENCES... 195 PATENT REFERENCES... 207 V
ILLUSTRATIONS 3.1 World Production of Phosphoric Acid............ 16 3.2 Phosphoric Acid Price History............... 26 4.1 Effect of Reaction Conditions on Crystal Form of Calcium Sulfate.............. 32 5.1 Occidental Chemical's Hemihydrate Process......... 53 5.2 Dihydrate System Flow Sheet........................ 211 5.3 Wet Process Acid by the Dihydrate System Estimated Capital Investment as a Function of Plant Design Capacity................... 68 5. 4 Dihydrate System Value of Product P2O5 as a Function of Plant Design Capacity, Stream Factor, and Phosphate Rock and Sulfuric Acid Costs.................. 72 5.5 Wet Process Phosphoric Acid by the Flow Sheet........................ 213 5.6 Hemihydrate/ Dihydrate System Estimated Capital Investment as a Function of Plant Design Capacity and Value of Product P205 at Various Capacities and Stream Factors......... 85 5.7 Hemihydrate System Flow Sheet........................ 217 5.8 Hemihydrate System Estimated Capital Investment as a Function of Plant Design Capacity and the P2O5 Product Value at Various Capacities and Stream Factors......... 97 5.9 Value of Uet Process Phosphoric Acid by Dihydrate, Hemihydrate, and s Value of Product P205 as a Function of Steam Value.... 101 6.1 Flow Diagram and Performance Data for of Phosphoric Acid........... 106 Vii
ILLUSTRATIONS 6.2 Purification of Wet Process Phosphoric Acid By Flow Sheet... 219 7.1 Processes to Recover Uranium from Wet Process Phosphoric Acid Flow Sheet... 221 7.2 Recovery of Uranium from Wet Process Phosphoric Acid Flow Sheet... 223 7.3 Recovery of Uranium from Wet Process Phosphoric Acid Product Value and Net Production Cost as a Function of Plant Size................ 174 B.l Phosphorus Pentoxide Recoveries at 25-35OC as a Function of the Solvent/Acid Volume Ratio and the Number of Extraction Stages.............. 184 B.2 Uranium Extraction Coefficients for DEPA/TOPO Agents in n-dodecane as a Function of Temperature......... 185 B.3 Uranium Extraction Coefficients at 25'C for DEPA/TOPO Agents in n-dodecane as a Function of TOP0 Concentration....................... 186 viii
TABLES 2.1 Capital and Production Costs for Making Wet Process Phosphoric Acid................. 6 2.2 Capital and Production Costs for Purification of Wet Process Phosphoric Acid......... 9 2.3 Capital and Production Costs for Recovery of Uranium from Wet Process Phosphoric Acid.... 13 3.1 Wet Process Phosphoric Acid Producers in the United States.................... 17 3.2 Major Wet Process Phosphoric Acid Producers Outside the United States.................. 20 3.3 Recent Sulfur Price History................. 27 3.4 Distribution by Grade of Marketable Phosphate Rock from Florida and North Carolina............... 29 5.1 Dihydrate Process Patent Summary....................... 43 5.2 Wet Process Phosphoric Acid by a Combination Hemihydrate/Dihydrate Process................ 51 5.3 Hemihydrate Process Patent Summary....................... 56 5.4 Dihydrate System Major Equipment....................... 61 5.5 Dihydrate System Utilities Summary...................... 62 5.6 Dihydrate Process Stream Flows........,............... 63 5.7 Dihydrate System Total Capital Investment.................. 66 5.8 Dihydrate System Capital Investment by Section................ 67 5.9 Dihydrate System Production Costs...................... 69 ix
TABLES 5.10 5.11 5.12 5.13 5.14 5.15 5.16 5.17 5.18 5.19 5.20 5.21 Dihydrate System Direct Operating Costs by Section (Thousand $/Yr.)..... 71 Major Equipment...................... 74 Utilities Summary..................... 75 Stream Flows........................ 76 Total Capital Investment.................. 80 Capital Investment by Section............... 81 Production Costs...................... 82 Direct Operating Costs by Section (Thousand $/Yr)..... 84 Hemihydrate System MajorEquipment...................... 88 Hemihydrate System Utilities Summary..................... 88 Hemihydrate System Stream Flows........................ 89 Hemihydrate System Total Capital Investment.................. 92
TABLES 5.22 5.23 5.24 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 Hemihydrate System Capital Investment by Section............... 93 Bemihydrate System Production Costs..................... 94 Hemihydrate System Direct Operating Costs by Section (Thousand $/Yr)..... 96 Production of Furnace Acid and Phosphorus in the United States................... 104 Purification of Wet Process Phosphoric Acid by Patent Summary...................... 108 Purification of Wet Process Phosphoric Acid by Chemical Methods Patent Summary...................... 120 Removal of Metal Impurities from Wet Process Phosphoric Acid Patent Summary...................... 125 Removal of Organic Impurities from Wet Process Phosphoric Acid Patent Summary...................... 127 Purification of Wet Process Phosphoric Acid by Major Equipment...................... 129 Purification of Wet Process Phosphoric Acid by Utilities Summary..................... 130 Purification of Wet Process Phosphoric Acid by Stream Flows,...................... 131 Purification of Wet Process Phosphoric Acid by Total Capital Investment................. 137 Xi
TABLES 6.10 Purification of Wet Process Phosphoric Acid by Capital Investment by Section............... 138 6.11 Purification of Wet Process Phosphoric Acid by Production Costs..................... 139 6.12 Purification of Wet Process Phosphoric Acid by Direct Operating Costs by Section (Thousand $/Yr)..... 141 6.13 Capital and Operating Cost Estimates for Electric Furnace Phosphorus.............. 142 6.14 Capital and Operating Cost Estimates for Furnace Phosphoric Acid................ 143 7.1 Uranium Content of Various Phosphate Rocks and of the Phosphoric Acid Produced Therefrom....... 145 7.2 Plants for the Recovery of Uranium from Wet Process Phosphoric Acid................ 147 7.3 Characteristics of Uranium Solvents,........... 148 7.4 Recovery of Uranium from Wet Process Phosphoric Acid Patent Summary...................... 153 7.5 Recovery of Uranium from Wet Process Phosphoric Acid Major Equipment....................... 162 7.6 Recovery of Uranium from Wet Process Phosphoric Acid Utilities Summary..................... 163 7.7 Recovery of Uranium from Wet Process Phosphoric Acid Stream Flows....................... 164 7.8 Recovery of Uranium from Wet Process Phosphoric Acid Total Capital Investment................. 169 7.9 Recovery of Uranium from Wet Process Phosphoric Acid Capital Investment by Section............... 170 7.10 Recovery of Uranium from Wet Process Phosphoric Acid Production Costs..................... 171 xii
TABLES 7.11 Recovery of Uranium from Wet Process Phosphoric Acid Direct Operating Costs by Section (Thousand $/Yr)..... 173 8.1 Concentration of Trace Minerals and Their Value in Comercial Phosphate Rocks in the United States.... 176 c.1 Wet Process Phosphoric Acid Compositions......... 187 c.2 Technical and Food Grade Acid Specifications and Analysis................ 188 xiii