ANS:A - separation of uranium oxide from its ore by H₂SO₄ in a Pachuca tank.

The separation of uranium oxide from its ore by H2SO4 in a Pachuca tank is a hydrometallurgical process commonly known as acid leaching or acid digestion. This process is used to extract uranium from its ores, which typically contain uranium oxide minerals such as uraninite (UO2) or pitchblende (U3O8). Here's how the process works:

1. Ore Preparation: The uranium ore is crushed and ground into fine particles to increase the surface area available for leaching. This step aims to expose as much of the uranium-bearing minerals as possible to the leaching solution.
2. Acid Leaching: The ground ore is then mixed with a leaching solution containing sulfuric acid (H2SO4). Sulfuric acid is chosen because it is highly effective at dissolving uranium oxide minerals, converting insoluble uranium compounds into soluble uranyl sulfate (UO2SO4). The reaction involved in the leaching process is typically: 𝑈𝑂2+2𝐻2𝑆𝑂4→𝑈𝑂2𝑆𝑂4+2𝐻2𝑂UO2​+2H2​SO4​→UO2​SO4​+2H2​O This reaction releases uranium from the ore matrix into the leaching solution, forming uranyl sulfate complexes.
3. Agitation in Pachuca Tank: The ore and leaching solution mixture is transferred to a Pachuca tank, which is a large, vertically oriented cylindrical vessel equipped with agitators. The agitation of the mixture in the Pachuca tank serves several purposes:
   • It promotes the mixing of the ore with the leaching solution, ensuring uniform contact and efficient extraction of uranium.
   • It helps maintain the suspension of the ore particles in the leaching solution, preventing settling and allowing for continuous contact between the solid and liquid phases.
   • It facilitates the oxygenation of the leaching solution, which can enhance the leaching kinetics by promoting the oxidation of uranium species.
4. Leaching Duration: The ore is typically leached in the Pachuca tank for a specified duration, allowing sufficient time for the uranium to dissolve into the leaching solution. The duration of leaching may vary depending on factors such as ore grade, particle size, and desired uranium recovery.
5. Separation and Recovery: After the leaching process is complete, the uranium-bearing solution, known as the pregnant leach solution (PLS), is separated from the solid residue (often referred to as "tailings" or "leach residue"). The PLS is then processed further to recover uranium through methods such as solvent extraction, ion exchange, or precipitation, depending on the specific requirements of the operation and the desired purity of the final uranium product.

Overall, the separation of uranium oxide from its ore by H2SO4 in a Pachuca tank is a critical step in the production of uranium, enabling the extraction of this valuable metal from its naturally occurring ores for use in various applications, including nuclear fuel production.