Experimental report on petrography of coal bulk

The sample of coal is received from the customer, need to make  petrographic specimen preparation for it.

1.Introduction

Equipment and consumables.

2.Mounting

Place the coals on the bottom of the silicone mold cup. Mix TJ2562 epoxy resin in proportion, After vacuum impregnation with Theta Vacuum cold mounting machine, the specimens were placed in Theta Mount pressure chamber for pressure mounting about 12h.

3.Grinding

 Grinding the specimens with ALPHA-600 automatic grinder&polisher，          abrasive paper P800→P2500.

4.Polishing

Polishing the specimens with ALPHA-600 automatic grinder&polisher, use SC polishing cloth with 3μm polycrystalline diamond suspension+ silica polishing suspension for rough polishing first.

Polishing with ALPHA-600 automatic grinder& polisher, use ZN polishing cloth with 50nm silica polishing suspension for fine polishing.

5.Observation

6.Analysis

    Since coal has many voids and is rich in fine cracks, vacuum mounting should be performed to remove air bubbles.

        Commence abrasive should be finer and with low pressure, because the coal is very fragile and easy to crack.

        Coal is brittle and fragile, and it is easy to have particles fall off during polishing, resulting in tiny scratches that are difficult to remove. So a lint-free polishing cloth should be selected and the entire polished surface should be kept under inward compressive stress. The choice of the final polishing cloth is more critical. The damping polishing cloth made of foaming rubber meets the requirements and is an ideal final polishing cloth.