How to extract iridium from iridium-containing waste. This is a very interesting topic because iridium is a rare and precious metal that has important applications in many fields, such as aerospace, medicine, chemistry, etc. However, the mining and processing of iridium will also produce a large amount of waste, which still contains a certain amount of iridium, and if it can be used effectively, it can save resources, reduce waste, and protect the environment.
So, how do you extract iridium from iridium-containing waste? This is a thought-provoking question because it involves complex chemical reactions and processes of physical separation, requiring specialized knowledge and technology. However, you don't have to worry, I will try my best to explain it to you in simple language and examples.
First of all, we need to know that iridium is a platinum group metal, which has similar properties to platinum, palladium, rhodium, osmium, ruthenium and other metals, they are all white or silver, have high density and melting point, have strong resistance to acids and alkalis, and are not easy to be oxidized or reduced. These characteristics make them widely used in industry, but they also make their separation and purification difficult, because their chemical activities are not very different from each other, and it is difficult to distinguish them by conventional methods.
Therefore, the extraction of iridium from iridium-containing waste requires the use of a technology called solvent extraction. Solvent extraction is a method of separating components in a mixture using two immiscible liquids, its principle is that different substances have different solubility in different solvents, and by adjusting the properties and proportions of solvents, certain substances can be transferred from one solvent to another, so as to achieve separation.
Specifically, the extraction of iridium from iridium-containing waste requires the following steps:
In the first step, the iridium-containing waste is crushed and ground to form fine particles, increasing its surface area for subsequent reaction and separation.
In the second step, iridium-containing waste particles are reacted with a mixture of concentrated nitric acid and concentrated hydrochloric acid to dissolve them into an acidic solution containing platinum group metals, a step called leaching. The conditions for leaching need to be well controlled to ensure complete dissolution of PGMs and to avoid dissolution of other impurities.
In the third step, an acidic solution containing platinum group metals is mixed with an organic solvent, which is a compound containing nitrogen and phosphorus called trioctyl phosphonic acid (TPA), which can form complexes with platinum group metals to extract them from the acidic solution, this step is called extraction. The extraction conditions also need to be controlled to ensure efficient transfer of PGMs and avoid the transfer of other impurities.
In the fourth step, an organic solvent containing platinum group metals is mixed with an alkaline solution, which is an ammonia-containing compound called ammonia, which reacts with the complexes of platinum group metals to separate them from the organic solvent, which is called reverse extraction. The conditions for reverse extraction also need to be controlled to ensure complete separation of PGMs and to avoid the separation of other impurities.
In the fifth step, the alkaline solution containing platinum group metals is concentrated and crystallized to form solid salts containing platinum group metals, which is called concentration and crystallization. Concentration and crystallization conditions also need to be controlled to ensure high purity of PGMs and to avoid the introduction of other impurities.
In the sixth step, the solid salts containing platinum group metals are smelted and electrolyzed to reduce them to metal platinum group elements, which is called melting and electrolysis. The melting and electrolysis conditions also need to be controlled to ensure the high quality of the PGMs and to avoid the influence of other impurities.
After the above six steps, the iridium element can be extracted from iridium-containing waste. Of course, this process is not simple, it requires precise instruments and equipment, strict operation and monitoring, professional personnel and technology, and adequate safety and environmental protection measures. However, it is also very valuable, which allows us to make better use of iridium, a rare and precious metal, and provides more possibilities for our scientific and technological and social development.