Hydrometallurgical process for nickel oxide ore

Abstract

The hydrometallurgical Process for a nickel oxide ore, which is capable of preventing inevitable operation shutdown of a leaching step and maintaining high operation efficiency as a whole process, in a trouble of the steps other than the leaching step, in a hydrometallurgical Process for a nickel oxide ore using a High Pressure Acid Leach. It is characterized in that, the hydrometallurgical Process for a nickel oxide ore using a High Pressure Acid Leach equipment equipped with the following means (a) to (c), in a trouble of the steps other than the above leaching step, the leached slurry discharged from the means (c), which is used in the above High Pressure Acid Leach equipment, is subjected to self-circulation inside the High Pressure Acid Leach equipment, by transferring to the means (a), which is used in the above High Pressure Acid Leach equipment, as well as by shutdown of receiving the ore slurry and the addition of sulfuric acid, in the above leaching step: means (a) to preliminarily increase temperature and pressure of the ore slurry; means (b) to form the leached slurry, by the addition of sulfuric acid to the ore slurry with preliminarily increased temperature and pressure, and leaching under blow of high-pressure steam and high-pressure air; means (c) to eliminate a pressurized state of the leached slurry formed.

1 . A hydrometallurgical Process for a nickel oxide ore using a High Pressure Acid Leach comprising:
 a preparation step of ore slurry for making a slurry of a nickel oxide ore,   a leaching step for obtaining a leached slurry by transferring of said ore slurry to a High Pressure Acid Leach equipment equipped with the following means (a) to (c), for leaching a nickel and a cobalt, and   a solid-liquid separation step of said leached slurry;   characterized in that, in a trouble of the steps other than the above leaching step, the leached slurry discharged from the means (c), which is used in the above High Pressure Acid Leach equipment, is subjected to self-circulation inside said High Pressure Acid Leach equipment, by shutdown of transfer to the above solid-liquid separation step, and transfer to the means (a), which is used in the above High Pressure Acid Leach equipment, as well as by shutdown of receiving the above ore slurry and the addition of sulfuric acid, in the above leaching step:   means (a) to preliminarily increase temperature and pressure of the ore slurry;   means (b) to form the leached slurry, by adding the sulfuric acid to the ore slurry with preliminarily increased temperature and pressure, and leaching under blow of high-pressure steam and high-pressure air;   means (c) to adjust a pressurized state of the leached slurry formed.   
   
   
       2 . The hydrometallurgical Process for a nickel oxide ore according to  claim 1 , characterized in that, in self-circulation of the above leached slurry inside the High Pressure Acid Leach equipment, pH of said leached slurry is adjusted at 3.0 to 5.0. 
   
   
       3 . The hydrometallurgical Process for a nickel oxide ore according to  claim 1 , characterized in that, in self-circulation of the above leached slurry inside the High Pressure Acid Leach equipment, temperature of the means (b), which is used in said High Pressure Acid Leach equipment, is 200 to 260° C. 
   
   
       4 . The hydrometallurgical Process for a nickel oxide ore according to any  claim 1 , characterized in that, each of the above means (a) to (c) uses the following apparatus:
 means of (a): a multistage heater for increasing temperature and pressure of the ore slurry stepwise,   means of (b): an autoclave for leaching the ore slurry at high temperature under high pressure, and forming the leached slurry with high temperature and high pressure, and   means of (c): a multistage flash tank for decreasing temperature and pressure of the leached slurry stepwise.   
   
   
       5 . The hydrometallurgical Process for a nickel oxide ore according to any  claim 1 , characterized in that, in the trouble of the steps other than the above leaching step, estimated shutdown time of the leaching step accompanying therewith is within a time required in the case of shutdown of the High Pressure Acid Leach equipment, separation of each apparatus and decreasing of temperature, and subsequent increasing of temperature again. 
   
   
       6 . The hydrometallurgical Process for a nickel oxide ore according to  claim 5 , characterized in that the above estimated shutdown time is within 12 hours. 
   
   
       7 . The hydrometallurgical process for a nickel oxide ore according to  claim 2 , characterized in that, in self-circulation of the above leached slurry inside the high pressure acid leach equipment, temperature of the means (b), which is used in said high pressure acid leach equipment, is 200 to 260° C. 
   
   
       8 . The hydrometallurgical process for a nickel oxide ore according to  claim 2 , characterized in that, each of the above means (a) to (c) uses the following apparatus:
 means of (a): a multistage heater for increasing temperature and pressure of the ore slurry stepwise,   means of (b): an autoclave for leaching the ore slurry at high temperature under high pressure, and forming the leached slurry with high temperature and high pressure, and   means of (c): a multistage flash tank for decreasing temperature and pressure of the leached slurry stepwise.   
   
   
       9 . The hydrometallurgical process for a nickel oxide ore according to  claim 3 , characterized in that, each of the above means (a) to (c) uses the following apparatus:
 means of (a): a multistage heater for increasing temperature and pressure of the ore slurry stepwise,   means of (b): an autoclave for leaching the ore slurry at high temperature under high pressure, and forming the leached slurry with high temperature and high pressure, and   means of (c): a multistage flash tank for decreasing temperature and pressure of the leached slurry stepwise.   
   
   
       10 . The hydrometallurgical process for a nickel oxide ore according to  claim 7 , characterized in that, each of the above means (a) to (c) uses the following apparatus:
 means of (a): a multistage heater for increasing temperature and pressure of the ore slurry stepwise,   means of (b): an autoclave for leaching the ore slurry at high temperature under high pressure, and forming the leached slurry with high temperature and high pressure, and   means of (c): a multistage flash tank for decreasing temperature and pressure of the leached slurry stepwise.   
   
   
       11 . The hydrometallurgical process for a nickel oxide ore according to  claim 2 , characterized in that, in the trouble of the steps other than the above leaching step, estimated shutdown time of the leaching step accompanying therewith is within a time required in the case of shutdown of the high pressure acid leach equipment, separation of each apparatus and decreasing of temperature, and subsequent increasing of temperature again. 
   
   
       12 . The hydrometallurgical process for a nickel oxide ore according to  claim 3 , characterized in that, in the trouble of the steps other than the above leaching step, estimated shutdown time of the leaching step accompanying therewith is within a time required in the case of shutdown of the high pressure acid leach equipment, separation of each apparatus and decreasing of temperature, and subsequent increasing of temperature again. 
   
   
       13 . The hydrometallurgical process for a nickel oxide ore according to  claim 4 , characterized in that, in the trouble of the steps other than the above leaching step, estimated shutdown time of the leaching step accompanying therewith is within a time required in the case of shutdown of the high pressure acid leach equipment, separation of each apparatus and decreasing of temperature, and subsequent increasing of temperature again. 
   
   
       14 . The hydrometallurgical process for a nickel oxide ore according to  claim 7 , characterized in that, in the trouble of the steps other than the above leaching step, estimated shutdown time of the leaching step accompanying therewith is within a time required in the case of shutdown of the high pressure acid leach equipment, separation of each apparatus and decreasing of temperature, and subsequent increasing of temperature again. 
   
   
       15 . The hydrometallurgical process for a nickel oxide ore according to  claim 8 , characterized in that, in the trouble of the steps other than the above leaching step, estimated shutdown time of the leaching step accompanying therewith is within a time required in the case of shutdown of the high pressure acid leach equipment, separation of each apparatus and decreasing of temperature, and subsequent increasing of temperature again. 
   
   
       16 . The hydrometallurgical process for a nickel oxide ore according to  claim 11 , characterized in that the above estimated shutdown time is within 12 hours. 
   
   
       17 . The hydrometallurgical process for a nickel oxide ore according to  claim 12 , characterized in that the above estimated shutdown time is within 12 hours. 
   
   
       18 . The hydrometallurgical process for a nickel oxide ore according to  claim 13 , characterized in that the above estimated shutdown time is within 12 hours. 
   
   
       19 . The hydrometallurgical process for a nickel oxide ore according to  claim 14 , characterized in that the above estimated shutdown time is within 12 hours. 
   
   
       20 . The hydrometallurgical process for a nickel oxide ore according to  claim 15 , characterized in that the above estimated shutdown time is within 12 hours.