Fig. 1
Results of analysing uranium and thorium isotopes in IAEA reference materials (RGU-1 and RGTh-1)
| Sample | Measured values | Reference value | Measured values | Reference value | |||
|---|---|---|---|---|---|---|---|
| 238U | 234U | 230Th | 232Th | 228Th | |||
| RGU-1 | 4649 ± 418 | 4893 ± 427 | 5004 ± 374 | 4940 ± 30 | 5 ± 2 | 6 ± 2 | <4 |
| 4557 ± 338 | 4777 ± 365 | 4811 ± 365 | 7 ± 3 | 6 ± 2 | |||
| 4797 ± 425 | 4723 ± 402 | 4886 ± 378 | 4 ± 3 | 5 ± 2 | |||
| 5288 ± 376 | 5489 ± 431 | 4768 ± 361 | 6 ± 2 | 5 ± 2 | |||
| Average | 4823 ± 39 | 4970 ± 40 | 4867 ± 38 | 6 ± 3 | 6 ± 3 | ||
| CV* | 0.81 | 0.82 | 0.78 | 50 | 50 | ||
| RGTh-1 | 75 ± 11 | 71 ± 11 | 70 ± 8 | 78 ± 6 | 3319 ± 206 | 3453 ± 214 | 3250 ± 90 |
| 88 ± 10 | 89 ± 9 | 73 ± 9 | 2987 ± 214 | 3173 ± 226 | |||
| 83 ± 9 | 84 ± 10 | 75 ± 8 | 3358 ± 231 | 2794 ± 205 | |||
| 79 ± 9 | 78 ± 9 | 69 ± 8 | 3335 ± 184 | 3252 ± 181 | |||
| Average | 81 ± 6 | 81 ± 6 | 72 ± 6 | 3250 ± 29 | 3168 ± 29 | ||
| CV* | 7.41 | 7.41 | 8.33 | 0.89 | 0.92 | ||
International values for 238U and 232Th in phosphate sedimentary rocks of different countries excluding the Tethys Sea
| Country | Activity concentration (Bq/kg) | |
|---|---|---|
| 238U | 232Th | |
| Sudan (Kurun) [15] | 684 | 0.83 |
| Sudan (Uro) [15] | 2598 | 2.5 |
| Sudan [31] | – | 7.5 |
| Tanzania (Arusha) [25] | 4641 | 717 |
| South Africa (Togo) [13] | 1300 | 30 |
| South Africa (Togo) [26] | 1300 | 110 |
| USA (Western) [13] | 1000 | 20 |
| USA (South Carolina) [32] | 4800 | – |
| Brazil [33] | – | 3238 |
| Russia (Kola) [13] | 40 | 80 |
| Russia (Kola) [26] | 90 | – |
| Russia (Kola) [14] | 30 | 80 |
| Pakistan (Hazara) [4] | – | 48 |
| Pakistan [34] | 440 | 50 |
| China [26] | 150 | – |
| Finland [12] | 10 | 10 |
International values (averages) for 238U and 232Th in different phosphate deposits of the Tethys Sea
| Country | Activity concentration (Bq/kg) | |
|---|---|---|
| 238U | 232Th | |
| Al-Jalamid, Saudi Arabia, this study | 378 ± 125 | 8 ± 6 |
| Saudi Arabia [20] | – | 39 |
| Jordan [28] | – | 2 |
| Jordan [26] | 1300–1850 | – |
| Jordan [4] | – | 19 |
| Israel [28] | – | 11 |
| Israel [26] | 1500–1700 | – |
| Egypt [29] | – | 395 |
| Egypt [18] | – | 19 ± 2 |
| Egypt [30] | 408 | 23.7 |
| Tunisia [28] | – | 29 |
| Algeria [28] | – | 64 |
| Morocco [26] | 1700 | 30 |
| Morocco [26] | 1500 | 30 |
| Morocco [13] | 1700 | 20 |
| Morocco [19] | 1600 | 10 |
| Sahara Western [13] | 900 | 7 |
| USA (Florida) [19] | 1000 | – |
| USA (Florida) [13] | 1500 | 20 |
Activity concentrations of uranium and thorium in the topsoil and waste layers
| Sample | Activity concentration (Bq/kg) | ||||
|---|---|---|---|---|---|
| U isotopes | Th isotopes | ||||
| 238U | 234U | 232Th | 230Th | 228Th | |
| Topsoil | 47 ± 8 | 51 ± 8 | 137 ± 13 | 46 ± 4 | 129 ± 11 |
| 89 ± 9 | 82 ± 9 | 66 ± 8 | 63 ± 7 | 67 ± 7 | |
| 61 ± 8 | 66 ± 10 | 112 ± 10 | 71 ± 8 | 104 ± 10 | |
| 44 ± 7 | 40 ± 7 | 135 ± 11 | 47 ± 6 | 111 ± 10 | |
| 96 ± 10 | 110 ± 10 | 86 ± 9 | 114 ± 10 | 96 ± 9 | |
| 59 ± 7 | 55 ± 7 | 97 ± 10 | 56 ± 7 | 95 ± 10 | |
| Average | 66 ± 7 | 67 ± 7 | 106 ± 8 | 66 ± 6 | 100 ± 8 |
| CV* | 10.61 | 10.45 | 7.55 | 9.1 | 8 |
| Overburden waste layer | 64 ± 6 | 68 ± 7 | 12 ± 3 | 63 ± 5 | 13 ± 3 |
| 52 ± 6 | 57 ± 6 | 9 ± 2 | 48 ± 6 | 9 ± 2 | |
| 55 ± 7 | 62 ± 9 | 7 ± 2 | 56 ± 5 | 7 ± 2 | |
| 85 ± 7 | 86 ± 7 | 9 ± 2 | 82 ± 9 | 8 ± 2 | |
| 71 ± 6 | 76 ± 6 | 12 ± 3 | 77 ± 8 | 11 ± 3 | |
| Average | 65 ± 6 | 70 ± 6 | 10 ± 3 | 65 ± 6 | 10 ± 3 |
| CV* | 9.23 | 8.57 | 30 | 9.23 | 30 |
| Intermediate waste layer | 312 ± 25 | 311 ± 25 | 5 ± 2 | 290 ± 27 | 5 ± 2 |
| 177 ± 18 | 189 ± 19 | 4 ± 2 | 168 ± 11 | 4 ± 2 | |
| 150 ± 14 | 160 ± 16 | 5 ± 2 | 174 ± 12 | 5 ± 2 | |
| 214 ± 21 | 234 ± 23 | 6 ± 2 | 222 ± 13 | 5 ± 2 | |
| 263 ± 22 | 276 ± 26 | 4 ± 2 | 271 ± 15 | 5 ± 3 | |
| Average | 223 ± 10 | 234 ± 10 | 5 ± 3 | 225 ± 9 | 5 ± 3 |
| CV* | 4.48 | 4.27 | 60 | 4 | 60 |
Activity concentration of uranium and thorium in high-grade raw phosphate ore and its physical beneficiation products (concentrate and reject)
| Sample | Activity concentration (Bq/kg) | ||||
|---|---|---|---|---|---|
| U isotopes | Th isotopes | ||||
| 238U | 234U | 232T | 230Th | 228Th | |
| Raw rock | 350 ± 35 | 396 ± 49 | 6 ± 1 | 388 ± 48 | 5 ± 2 |
| 351 ± 47 | 375 ± 50 | 9 ± 3 | 348 ± 53 | 8 ± 3 | |
| 367 ± 46 | 406 ± 41 | 10 ± 3 | 325 ± 42 | 7 ± 2 | |
| 454 ± 33 | 468 ± 38 | 8 ± 2 | 489 ± 36 | 8 ± 2 | |
| 389 ± 46 | 411 ± 42 | 8 ± 1 | 422 ± 43 | 9 ± 2 | |
| 364 ± 33 | 358 ± 32 | 11 ± 3 | 349 ± 52 | 12 ± 2 | |
| 353 ± 36 | 388 ± 45 | 4 ± 1 | 345 ± 43 | 3 ± 2 | |
| 367 ± 36 | 375 ± 45 | 7 ± 2 | 382 ± 43 | 6 ± 3 | |
| 405 ± 58 | 423 ± 61 | 7 ± 2 | 395 ± 57 | 8 ± 2 | |
| Average | 378 ± 19 | 400 ± 20 | 8 ± 5 | 383 ± 18 | 7 ± 4 |
| CV* | 5 | 5 | 62.5 | 4.7 | 57.1 |
| Concentrate | 459 ± 47 | 471 ± 49 | 7 ± 1 | 463 ± 36 | 5 ± 2 |
| 542 ± 55 | 569 ± 57 | 5 ± 2 | 520 ± 41 | 4 ± 2 | |
| 557 ± 53 | 568 ± 55 | 11 ± 3 | 544 ± 49 | 7 ± 2 | |
| 442 ± 45 | 466 ± 45 | 10 ± 2 | 430 ± 47 | 9 ± 2 | |
| 475 ± 48 | 578 ± 58 | 6 ± 2 | 548 ± 54 | 8 ± 2 | |
| 622 ± 59 | 684 ± 61 | 7 ± 2 | 671 ± 66 | 8 ± 2 | |
| 399 ± 48 | 413 ± 46 | 4 ± 1 | 385 ± 50 | 4 ± 2 | |
| 555 ± 56 | 540 ± 54 | 5 ± 2 | 697 ± 56 | 4 ± 2 | |
| 439 ± 54 | 485 ± 59 | 6 ± 2 | 466 ± 49 | 4 ± 2 | |
| 488 ± 48 | 491 ± 51 | 8 ± 2 | 454 ± 50 | 6 ± 2 | |
| 539 ± 57 | 566 ± 59 | 5 ± 2 | 525 ± 47 | 4 ± 2 | |
| 503 ± 50 | 526 ± 57 | 9 ± 2 | 478 ± 47 | 7 ± 2 | |
| Average | 502 ± 25 | 530 ± 25 | 7 ± 2 | 515 ± 24 | 6 ± 2 |
| CV* | 5 | 4.72 | 28.57 | 4.66 | 33.33 |
| Reject | 327 ± 43 | 365 ± 43 | 5 ± 2 | 371 ± 45 | 5 ± 3 |
| 378 ± 42 | 383 ± 43 | 6 ± 2 | 376 ± 39 | 7 ± 2 | |
| 366 ± 47 | 412 ± 48 | 5 ± 2 | 346 ± 50 | 6 ± 2 | |
| 355 ± 41 | 403 ± 44 | 6 ± 2 | 563 ± 46 | 6 ± 2 | |
| 337 ± 44 | 394 ± 47 | 5 ± 1 | 386 ± 39 | 5 ± 2 | |
| 346 ± 42 | 344 ± 43 | 5 ± 2 | 361 ± 46 | 7 ± 2 | |
| Average | 352 ± 16 | 384 ± 16 | 5 ± 3 | 401 ± 16 | 6 ± 4 |
| CV* | 4.55 | 4.71 | 60 | 4 | 66.67 |
Activity concentration of uranium and thorium in low-grade raw phosphate ore and the chemical beneficiation products (concentrate and reject)
| Sample | Activity concentration (Bq/kg) | ||||
|---|---|---|---|---|---|
| U isotopes | Th isotopes | ||||
| 238U | 234U | 232Th | 230Th | 228Th | |
| Raw rock | 293 ± 30 | 260 ± 23 | 9 ± 2 | 267 ± 18 | 7 ± 2 |
| 243 ± 26 | 255 ± 30 | 6 ± 2 | 256 ± 19 | 7 ± 3 | |
| 268 ± 32 | 253 ± 27 | 6 ± 2 | 251 ± 22 | 6 ± 3 | |
| 316 ± 34 | 274 ± 31 | 8 ± 3 | 298 ± 18 | 7 ± 3 | |
| Average | 280 ± 11 | 261 ± 10 | 7 ± 3 | 268 ± 9 | 7 ± 3 |
| CV* | 3.93 | 3.83 | 42.86 | 3.36 | 42.86 |
| Concentrate | 393 ± 52 | 421 ± 54 | 6 ± 2 | 408 ± 58 | 7 ± 2 |
| 508 ± 55 | 534 ± 61 | 8 ± 2 | 601 ± 64 | 8 ± 2 | |
| 436 ± 63 | 416 ± 60 | 10 ± 2 | 430 ± 47 | 8 ± 2 | |
| 422 ± 52 | 414 ± 51 | 7 ± 2 | 437 ± 54 | 6 ± 2 | |
| 390 ± 46 | 417 ± 45 | 7 ± 2 | 382 ± 53 | 6 ± 2 | |
| 440 ± 46** | 457 ± 45 | 7 ± 2 | 446 ± 51 | 6 ± 2 | |
| 490 ± 55** | 486 ± 61 | 11 ± 2 | 430 ± 47 | 8 ± 2 | |
| Average | 440 ± 19 | 449 ± 19 | 8 ± 4 | 448 ± 19 | 7 ± 4 |
| CV* | 4.32 | 4.23 | 50 | 4.24 | 57.14 |
| Reject | 86 ± 7 | 82 ± 7 | 3 ± 2 | 92 ± 8 | 2 ± 1 |
| 97 ± 7 | 91 ± 7 | 4 ± 2 | 103 ± 9 | 5 ± 2 | |
| 62 ± 7 | 68 ± 6 | 3 ± 1 | 75 ± 7 | 3 ± 2 | |
| 113 ± 12 | 96 ± 9 | 5 ± 2 | 101 ± 10 | 4 ± 2 | |
| 78 ± 9 | 91 ± 9 | 4 ± 2 | 88 ± 11 | 5 ± 2 | |
| Average | 87 ± 6 | 86 ± 6 | 4 ± 3 | 92 ± 6 | 4 ± 3 |
| CV* | 6.9 | 6.98 | 75 | 6.52 | 75 |