Identification of Ore Polished Slice

1. Equipment

(1)Polarizing, reflection microscope or emission polarizing microscope, and equipped with computer or mechanical station, counter, image analyzer

(2)Microphotographic system

2. Rock Flake

The area of flake is 40mm×25mm with 10mm thickness and smooth surface, mirror-like bright.

3. Preparatory Work Before Identification

3.1 Pressure flat piece

Place the back side of the slide on the glue (3.2.2) that adheres to the slide and press the smooth surface horizontally with a hand press (3.2.1).

3.2 Power supply

Turn on the power supply of the reflector polarizing microscope, turn the transformer knob, gradually adjust the brightness degree from weak to strong, to achieve the required lighting effect.

3.3 Adjustment of Reflection Polarizing Microscope

3.3.1 Center correction of objective lens

Methods Center correction was performed with the same polarizing light microscope (see 5.3 in DZ/T 0275.4-2015).

3.3.2 Adjustment of reflector

First, place the polished section on the microscope platform; Then, after setting the microscope in focus, the light with the shape of circle is cast on the polished section; Next narrow the aperture of the field of view, and turning it into a small bright spot. Move the rotation axis of the reflector to make the small bright spot in the center of the cross wire is symmetrically bisected, indicating the correct position of the reflector.

3.3.3 Adjustment of aperture of field of view

After the adjustment of the reflector, narrow the aperture of the field of vision. When the bright circle on the aperture becomes smaller, the boundary is blurred. Until there is color, turn the lens handle of the field of vision, move the lens forward and backward, adjust the lens to the clear and colorless astigmatism of the field of vision, and then open the aperture of the field of vision.

3.3.4 Adjustment of aperture and aperture

When above adjustment is finished, narrow the aperture of the field of view, remove the eyepiece, and observe directly from the lens tube. Open and close the aperture aperture on the lens surface of the objective lens, and adjust the aperture edge to coincide with the lens circle on the objective lens.

3.3.5 Calibration of polarizer

(1)The light plate containing graphite or molybdenite is placed under the mirror, and the strip section particles are selected under the front polarizer, and the platform is rotated to make the long axis direction of the particles parallel to the cross wire of the ocular. The mineral reflection color at this position is the brightest, that is, the vibration direction of the front polarizer. Generally, the vibration direction of the fixed front polarizer is east-west direction.

(2)After adjusting the front polarizer, push in the upper polarizer and rotate the platform for one round. The mineral has four extinction times, and the distance between two extinction positions is 90°. At the same time, the polarization color depth at the Angle of 45° is consistent, indicating that the polarizer is completely orthogonal.

4. Observe Ore Specimen with Naked Eye and Magnifying Glass

Firstly, the mineral composition and structure of the ore are preliminarily identified by naked eye observation and magnifying glass observation.

5. Identification of Ore Polished Slice by Reflective Microscope

5.1 Mineral composition identification

5.1.1 Metallic minerals

Metal minerals were identified in terms of species, characteristics, mineral generations and symbiotic associations, difficult minerals, mineral particle size and mineral content.

5.1.2 Gangue mineral species

The type, combination, distribution of transparent minerals and their relationship with metallic minerals

5.2 Ore structure

The structure types, crystal structure characteristics, solid solution decomposition structure characteristics, metasomatic structure characteristics, stress structure characteristics were analyzed

5.3 Ore structure

Ore structure types, uniform structure characteristics, non-uniform structure characteristics (parallel structure, circular structure, cross structure, cavity structure)

6. Ore Named

Named according to industrial grade、Named after metallic minerals. ccording to the industrial grade, ore structure to participate in the naming

7. Quality Inspection

Mineral composition identification of ore. Metallic minerals(Opaque minerals): According to the optical characteristics of metallic minerals under the reflective microscope (color, reflectivity, polychromism, interference color, etc.) And crystallographic properties(Crystal morphology, twinning, Microhardness, cleavage, etc),Determining the classification and nomenclature of metallic minerals. We should also identify the characteristics of mineral alteration, deformation and grain size etc.. For gangue minerals(transparent minerals), the types of gangue minerals are identified with thin section identification. And then, Count the content of various minerals. At last, we Identify ore structure (crystal structure, metasomatic structure, deformation structure, etc.) and identification of ore structure.

8. Ore identification records and inspection

9. Implementation standard:

DZ/T0275.5-2015 Technical specification for rock and mineral identification part 5: ore polished slice identification.