Understanding Nucleation and Seeding in Precipitation Processes

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In summary, the conversation discusses the concepts of nucleation and seeding in a precipitation process involving copper and calcium hydroxide. The process involves recirculating the slurry to promote crystal growth, making it easier to separate from the solution. This is known as nucleation and seeding, where small particles induce the formation of larger crystals. Pumping the growing crystals back to the solution allows for longer contact time and quicker separation.
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lenin_yuweh
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Hi!

I seem to be out of the loop at work. Too embarrass to ask my coworkers to explain it to me.

Can anyone explain what nucleation and seeding is?

Our process is basically a precipitation process where copper is precipitated by reacting Ca(OH)2 to Cu(OH)2. We have a sedimentation tank to separate the slurry from the filtrate. What I don't understand is how recirculation, pump sucks the slurry below and returns it to the calcium feeding tank, improve slurry formation. They mentioned nucleation and seeding enhancement. I don't get how "crystals" can form in a slurry or is a slurry considered a crystals?
 
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Your slurry is likely a finely divided solid form of the Cu(OH)2 you seek. If these solids are crystalline in any way, they induce further solid to form on their surfaces. This causes the finely divided slurry form larger particles which are easier to remove by settling or filtration. So the initially formed very small particles induce the growth of a much larger particle. It is called "nucleation" or "seeding".

Pumping these growing "seed" crystals back to the Calcium feed tank let's those particles stay in contact with the copper solution longer thus allowing for larger crystal growth and a slurry that separates more quickly.
 

1. What is nucleation and seeding in science?

Nucleation and seeding refer to the process of creating a new phase or structure in a material by introducing foreign particles or surfaces that act as starting points for the formation of the new phase.

2. What are the applications of nucleation and seeding?

Nucleation and seeding have various applications in different fields such as material science, chemistry, and engineering. They are used to control the formation of crystals, improve the properties of materials, and create new materials with desired properties.

3. How does nucleation and seeding affect crystal growth?

Nucleation and seeding play a crucial role in crystal growth. They provide a surface for the crystal to grow on and determine the size, shape, and orientation of the resulting crystal. The presence of nucleation and seeding can also affect the rate of crystal growth.

4. What factors influence the efficiency of nucleation and seeding?

The efficiency of nucleation and seeding can be influenced by several factors, including the type and concentration of foreign particles or surfaces, temperature, pressure, and the chemical composition of the material being nucleated. The presence of impurities or defects can also affect the efficiency of nucleation and seeding.

5. Can nucleation and seeding be controlled?

Yes, nucleation and seeding can be controlled to a certain extent by adjusting the experimental conditions such as temperature, pressure, and concentration of foreign particles. However, complete control over nucleation and seeding is challenging due to the complex nature of the process.

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