Vermiculite Dataset

Material description

Vermiculite is a hydrated magnesium aluminum silicate mineral which resembles mica in appearance. It is found in various parts of the world including Australia, Brazil, Bulgaria, Kenya, Russia, South Africa, Uganda, USA and Zimbabwe.

Vermiculite is mined using open cast mining techniques where the ore is separated from other minerals and then screened or classified into several basic particle sizes. Every care is taken in mining operations to minimize the impact on the environment and to restore land to its natural condition when mining ends.

Vermiculite, when subjected to heat, exfoliates to form elongated concertina like particles which are lightweight, incombustible, compressible, highly absorbent, and non-reactive. Exfoliated vermiculite particles can have high cation exchange capacity and their surface chemistry may be modified.

Exfoliated vermiculite is used in a wide number of markets including construction, industrial, horticulture and agriculture.

The dry sample of vermiculite is sieved into several
fractions according to the granulometric classification (coarse, medium, fine, superfine and micron) and its application depends on this classification.

The commercial value of vermiculite depends on
impurities contained in ores, or the fiber concentration in each sample.

Dataset description

Lighting conditions (for image capturing)

Test Case 1 (TC1): fluorescent lamp
Test Case  2 (TC2): natural lighting
Test Case 3 (TC3): LED Lamp

 
Sample Classes (Based on the granulometric classification and fiber concentration). It was acquired 10 images for each class.

Class 1:  Medium size with high concentration of fibers
Class 2:  Medium size with low fiber concentration
Class 3:  Fine size with high fiber concentration
Class 4:  Fine size with low fiber concentration
Class 5:  Superfine size with high fiber concentration
Class 6:  Superfine size with low fiber concentration
Class 7:  Micron size with high fiber concentration
Class 8:  Micron size with low fiber concentration

  
Image identification: (examples)

TC1C1_I1.JPG = Fluorescent lamp - Class 1 - Image 1

TC2C8_I10.JPG = Natural lighting - Class 8 - Image 10

TC3C3_I4.JPG = LED lamps - Class 3 - Image 4

Applications

Most vermiculite is used in its exfoliated form.  Exfoliated vermiculite possesses a number of useful attributes. Aside from its very low density, it has low thermal conductivity, is non-combustible, odorless, thermally stable, sterile and insoluble in water.

Horticulture

 Vermiculite is widely used as a component of potting mixes for plant propagation. In this capacity vermiculite aids aeration and water retention. 

Fire Protection

 Vermiculite may be combined with Cement or Plaster and other materials to manufacture spray-applied fire resistant coatings for use on structural steel. 

Refractories

When mixed with silicates and other binders, vermiculite is used to manufacture insulating boards for use in the aluminium industry and other refractory applications.

Friction Linings

Vermiculite is now used extensively in the friction lining industry as a safe alternative to asbestos.

Method for image capturing:

• Sony DSC-W350 Photo Camera, 14.1 Megapixels, Super HAD CCD sensor type 1 / 2.3 (7.76 mm), Carl Zeiss Vario-Tessar lenses.

•  Sony universal tripod and support table.

• Wooden box for ore storage with dimensions of 11 cm x 11 cm x 4 cm.

• Distance between the camera lens and the ore of 11 cm.

•  Image resolution of 5 megapixel.

Fig. 1 - Fluorescent Lamp (TC1)    Fig. 2 - LED Lamp (TC3)

Fig. 3 - Natural lighting (TC2)