Define Digestion and Ostwald Ripening Quiz and Flashcards

Study Notes

Digestion and Ostwald Ripening

Digestion is a process where the precipitation is heated below boiling point for 30 minutes to an hour to allow the precipitate to grow and have better characteristics.
Ostwald ripening is a process where smaller particles in the solution dissolve and deposit into larger particles, also known as digestion.

Mother Liquor

Mother liquor is the solution from which the precipitate is formed, and it is left over after crystallization.

Colloidal Solution

A colloidal solution is a dispersion of particles of one type of substance among another substance that acts as the solute.
Colloidal particles range from 1 to 100 ppm and do not settle down easily, making them difficult to filter out.

Primary Layer and Counter Layer

The primary layer is the layer of adsorbed substance that is directly attached to the absorbed materials.
The counter layer, or secondary layer, is a substance added to the sample solution to facilitate precipitation.
The counter layer completely neutralizes the primary layer, resulting in an overall neutral charge.

Coagulation and Peptization

Coagulation is the process of particles collecting or clamping together, forming large particles with opposite charges that aggregate together and settle at the bottom.
Peptization is the process of reversing coagulation, where a coagulated colloid reverts to its original dispersed colloidal suspension state.

Coprecipitation and Occlusion

Coprecipitation is the process of simultaneously precipitating more than one compound from a solution, resulting in contamination of the precipitate.
Occlusion is the process of trapping materials that are not part of the crystal structure within the crystal as it grows.

Inclusion and Surface Adsorption

Inclusion refers to the trapping of ions with similar size and charge within the crystal structure.
Surface adsorption results in the primary absorbed layer of lattice ions in excess on the surface of the precipitate, which can be removed by washing or replacing ions.

Isomorphous Replacement and Post-Precipitation

Isomorphous replacement occurs when two compounds have the same type of formula and crystallize in similar geometric forms, allowing one ion to replace another in a crystal.
Post-precipitation is a slow equilibrium process where another substance forms a precipitate with the precipitating reagent when the precipitate is allowed to contact the mother liquor.

Mixed Crystal

A mixed crystal, also known as a solid solution, is a substance in which crystals contain atoms from two different substances.

Description

Learn about the processes of digestion and Ostwald ripening in metallurgy, where the precipitation is heated to enhance characteristics and smaller particles dissolve to form larger crystals. Understand how these techniques are used in the field of metallurgy.