Characteristics of clay minerals
- 4.1 Cation – exchange capacity. The ability of clay minerals to adsorb certain cations/anions and their retention around...
- 4.2 Swelling capacity. If dry clay minerals are allowed to adsorbed water in a controlled environment, water is added...
- 4.3 Surface charge properties. The surface charge of clay minerals affects various chemical...
What is the chemical formula of clay?
The idealized formula of kaolinite is Al2Si2O5 (OH)4. Clay is a hydrous aluminium phyllosilicate. It often has various amounts of Mg, Fe, alkali metals, and alkaline earths. Some other clay mineral groups are ones like montmorillonite which is a hydrated sodium calcium aluminium magnesium silicate hydroxide- (Na,Ca)0.33 (Al,Mg)2Si4O10 (OH)2·nH2O.
What causes chemical properties?
What are the properties of pure substance?
- Pure substances are mostly homogeneous in nature containing only one type of atoms or molecules.
- These substances mainly have a constant or uniform composition throughout.
- The substances have fixed boiling and melting points.
What are the physical properties of clay?
Soil Physical Properties of Clay, Sand, and Silt
- Clay Soil Properties. The soil particles in clay soil are very small, making the soil thick and dense. Clay has more plasticity than normal dirt.
- Sand Soil Properties. Sandy soils tend to be acidic and have high drainage rates. ...
- Silt Soil Properties. Soils with high silt content have a slippery feeling because of the shape of its particles. ...
Is there a chemical formula for clay?
There is no specific formula for clay. Naturally occurring clay is a substance that is plastic due to particle size and geometry as well as water content, and becomes hard, brittle and non–plastic upon drying or firing.
What is the chemical property of clay?
Physical and Chemical Properties of Clays Some swell easily and may double in thickness when wet. Most have the ability to soak up ions (electrically charged atoms and molecules) from a solution and release the ions later when conditions change. Water molecules are strongly attracted to clay mineral surfaces.
What are the chemical components of clay?
Clay minerals are composed essentially of silica, alumina or magnesia or both, and water, but iron substitutes for aluminum and magnesium in varying degrees, and appreciable quantities of potassium, sodium, and calcium are frequently present as well.
What is the chemical formula of clay?
Kaolinite is a clay mineral of chemical formula Al2O3 2SiO2·2H2O that has a structure of 1:1 uncharged dioctahedral layer where each layer consists of single silica tetrahedral sheet and single alumina octahedral sheet [123,124].
What is the physical properties of clay?
Plasticity, tensile strength, texture, shrinkage, porosity, fusibility and colour after burning are the physical properties which are the most important in determining the value of clay.
What are the five characteristics of clay?
What Are the Characteristics of Clay Soil?Small Particle Size. Clay soils have small particles. ... Affinity for Water. According to the USGS, "clay minerals all have a great affinity for water. ... Fertility. Water isn't the only substance clay holds. ... Low Workability. ... Warming. ... Improvability.
Can you eat clay?
Clay is POSSIBLY UNSAFE when taken by mouth for a long period of time. Eating clay long-term can cause low levels of potassium and iron. It might also cause lead poisoning, muscle weakness, intestinal blockage, skin sores, or breathing problems.
What is the chemical composition of clay used in pottery?
Clay is a group of minerals in earth that is granular; plastic, when mixed with a little water; or hard and brittle, if combusted. The clay is composed of hydrated aluminum silicates, with the addition of an appreciable amount of other elements: magnesium, iron, calcium, and potassium [3,4].
What kind of material is clay?
Clay is a soft, loose, earthy material containing particles with a grain size of less than 4 micrometres (μm). It forms as a result of the weathering and erosion of rocks containing the mineral group feldspar (known as the 'mother of clay') over vast spans of time.
What is the scientific name for clay?
The main groups of clays include kaolinite, montmorillonite-smectite, and illite. Chlorite, vermiculite, talc, and pyrophyllite are sometimes also classified as clay minerals.
What is the chemical composition of silt?
The fine silt fraction consists of quartz, kaolinite, chlorite, hydromica, smectite, and feldspars. The medium silt fraction consists of quartz, kaolinite, mica, and feldspars.
Abstract
Chemical properties of clays are very important to the understanding of their behaviour. The electrical charge and colloidal size of clay mineral particles make them hydrate and interact so that their hydraulic conductivity and stress/ strain properties are quite different from those of sandy soil.
Keywords
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Further Reading
Blackburn, W.H. and Dennen, W.H. (1994). Principles of Mineralogy (2nd ed.). William C. Brown, Dubuque, IA. Google Scholar
Abstract
Clay minerals such as kaolinite, smectite, chlorite, micas are main components of raw materials of clay and formed in presence of water. A large number of clays used to form the different structure which completely depends on their mining source.
1. Introduction
Georgius Agricola (1494–1555), the founder of geology, was seemingly the first who gave the definition of clay in 1546. It has been modified several times due to which the clay definition raises the questions related of constituents of clay and implicitly which was very important [ 1 ].
2. Structure and chemical composition of clay minerals
The properties that define the composition of clay minerals are derived from chemical compounds present in clay minerals, symmetrical arrangement of atoms and ions and the forces that bind them together. The clay minerals are mainly known as the complex silicates of various ions such as aluminum, magnesium and iron [ 13 ].
3. Classification of clay minerals
The aluminosilicate layers comprises of the basic structural units of phyllosilicates which is formed by the combination of tetrahedral and octahedral sheets bound by shared oxygen atoms.
4. Characteristics of clay minerals
Clay minerals are considered as gift for human beings as they are exploring the clay minerals continuously through research as these are of very low cost, environment friendly, easily available and non – toxic.
5. Characterization of clay minerals
At present, identification and characterization of clay minerals can be done in easier way using modern analytical techniques such as Nitrogen Adsorption Isotherm, X-Ray diffraction (XRD), Fourier-Transform Infra-Red (FT-IR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Zeta potential and Thermal Gravimetric Analysis (TGA).
6. Modification of naturally occurring clay minerals
Naturally occurring clay minerals has mixed cations present on the surface and in interlayer space due to which it is impossible to use clay minerals for certain purposes as surface properties do not allow.
What property of clay minerals causes ions in solution to be fixed on clay surfaces or within internal sites?
The property of clay minerals that causes ions in solution to be fixed on clay surfaces or within internal sites applies to all types of ions, including organic molecules like pesticides . Clays can be an important vehicle for transporting and widely dispersing contaminants from one area to another.
How big is a clay?
The term "clay" is applied both to materials having a particle size of less than 2 micrometers (25,400 micrometers = 1 inch) and to the family of minerals that has similar chemical compositions and common crystal structural characteristics (Velde, 1995) described in the next section. Clay minerals have a wide range of particle sizes from 10's ...
What are the minerals that are used in manufacturing?
Clays and clay minerals have been mined since the Stone Age; today they are among the most important minerals used by manufacturing and environmental industries. The U.S. Geological Survey (USGS) supports studies of the properties of clays, the mechanisms of clay formation, and the behavior of clays during weathering. These studies can tell us how and where these minerals form and provide industry and land-planning agencies with the information necessary to decide how and where clay and clay mineral deposits (fig. 1) can be developed safely with minimal effects on the environment.
What is the process of altering a mineral to more stable forms?
Diagenesis is the in-place alteration of a mineral to more stable forms, excluding surficial alteration (which is weathering); diagenesis occurs, for example, when minerals stable in one depositional environment are exposed to another by burial and compaction. Common silicate materials such as quartz, feldspars, and volcanic glasses, as well as carbonates, noncrystalline iron oxides, and primary clay minerals, are transformed during diagenesis into more stable clay minerals mainly by dissolution and recrystallization.
What can be produced by alteration of rocks to clay minerals?
Extensive alteration of rocks to clay minerals can produce relatively pure clay deposits that are of economic interest (for example, bentonites却rimarily montmorillonite丘sed for drilling muds and clays used in ceramics).
Why does clay swell?
Environmental industries use both these properties to produce homogeneous liners for containment of waste. The process by which some clay minerals swell when they take up water is reversible. Swelling clay expands or contracts in response to changes in environmental factors (wet and dry conditions, temperature).
What are the materials that are transformed during diagenesis?
Common silicate materials such as quartz, feldspars, and volcanic glasses, as well as carbonates, noncrystalline iron oxides, and primary clay minerals, are transformed during diagenesis into more stable clay minerals mainly by dissolution and recrystallization.
What is clay chemistry?
Clay chemistry is an applied subdiscipline of chemistry which studies the chemical structures, properties and reactions of or involving clays and clay minerals. It is a multidisciplinary field, involving concepts and knowledge from inorganic and structural chemistry, physical chemistry, materials chemistry, analytical chemistry, organic chemistry, ...
What is clay used for?
Some clay minerals ( kaolinite) are used as carrier material for fungicides and insecticides . The weathering of many rock types produce clay minerals as one of its last products. The understanding of these geochemical processes is also important for the understanding of geological evolution of landscapes and macroscopic properties ...
What is the study of clay?
The study of the chemistry (and physics) of clays and clay minerals is of great academic and industrial relevance as they are among the most widely used industrial minerals, being employed as raw materials (ceramics, pottery, etc.), adsorbents, catalysts, additives, mineral charges, medicines, building materials and others.