Granulation of potassium sulfate |
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| 申请号 | US32550473 | 申请日 | 1973-01-22 | 公开(公告)号 | US3853490A | 公开(公告)日 | 1974-12-10 |
| 申请人 | INT MINERALS & CHEM CORP; | 发明人 | BOEGLIN A; CHOWNING E; TSCHAPPLER S; | ||||
| 摘要 | Potassium sulfate crystals are granulated by first preparing a potassium sulfate feed material sized such as it is at least 50% -6 +65 mesh, 10% to 30% -200 mesh, with the remainder being -65 +200 mesh. The sized crystals are wetted to a moisture content of 7 to 12 percent by weight of the crystals. A small amount of a surface active agent such as disodium 4-dodecylated oxydibenzene sulfonate is incorporated in the admixture, and the mass granulated and dried in a rotating, tubular granular drier. Product temperature is maintained below a maximum of 550*F. and the maximum temperature of gases contacting the product is maintained below 1,200*F. | ||||||
| 权利要求 | 1. A METHOD FOR GRANULATING POTASSIUM SULFATE COMPRISING ESTABLISHING A MASS OF POTASSIUM SULFATE CRYSTALS CHARACTERIZED BY (1) CRYSTAL SIZE DISTRIBUTION OF AT LEAST 50 PERCENT BY WEIGHT -6+65 MESH, ABOUT 10 TO 30 PERCENT BY WEIGHT, -200 MESH, WITH THE REMAINDER BEING ESSENTIALLY -65 +200 MESH; (2) A MOISTURE CONTENT IN THE RANGE OF ABOUT 7 TO ABOUT 12 PERCENT BY WEIGHT OF THE CRYSTALS; AND (3) THE PRESENCE OF A SURFACE ACTIVE AGENT CAPABLE OF SUBSTANTIALLY ENCHANCING POTASSIUM SULFATE CRYSTAL GROWTH IN THE AMOUNT OF ABOUT 0.025 TO ABOUT 0.075 PERCENT BY WEIGHT OF THE CRYSTALS, ROLLING SAID MASS IN A CONFINED BED ON A SUBSTANTIALLY SMOOTH MOVING SURFACE TO FROM GRANULES, AND DRYING SAID GRANULES TO A MOISTURE CONTENT OF LESS THAN ABOUT 1 2 OF 1 PERCENT BY HEAT EXCHANGE BETWEEN SAID GRANULES AND HOT COMBUSTION GASES, THE MAXIMUM TEMPERATURE OF GASES IN CONTACT WITH SAID GRANULES BEING MAINTAINED AT LEAST THAN ABOUT 1,200*F., AND THE MAXIMUM TEMPERATURE REACHED IN THE DRYINNG STEP BEING MAINTAINED BELOW ABOUT 550*F. 2. The method in accordance with claim 1 in which said mass is subject to heat exchange with combustion gases at a temperature less than about 1200*F. during the granulation step. 3. The method in accordance with claim 2 in which said crystal mass contains moisture in the amount of about 7.5 to 9 percent by weight of the crystals. 4. The method in accordance with claim 3 in which said surface active agent is present in the amount of about 0.05 percent by weight of the crystals. 5. The method in accordance with claim 4 in which said surface active agent is disodium 4-dodecylated oxydibenzene sulfonate. 6. The method in accordance with claim 5 in which the moiSture content of said mass is derived from mother liquor from which potassium sulfate is crystallized. |
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