Amorphous Graphite – A New Carbon Material with Unique Properties

  • Excellent acid-alkali resistance and oxidization resistance.
  • Good plasticity and adhesion force.
  • High electrical & thermal conductivity, and high temperature resistance.
A pile of amorphous graphite is displayed.
Description

Amorphous graphite (aphanitic or cryptocrystalline graphite) is a dense aggregate composed of tiny natural graphite crystals, and also known as microcrystalline graphite. It is gray-black or steel-gray with a metallic luster. It has soft texture, feels smooth, and dyes hands easily. Besides, it has stable chemical properties, good thermal and electrical conductivity, high temperature resistance, acid and alkali resistance, corrosion resistance, and oxidation resistance. It is widely used in casting, coating, batteries, carbon, and other industries because of its small crystal size (grain size < 1 μm), strong plasticity, and good adhesion.

Amorphous graphite is divided into two categories based on whether it contains iron or not: ferrous amorphous graphite (WT) and ferrous-free amorphous graphite (W). The technical indicators and main uses of each type of amorphous graphite are shown in the table below.

Table 1: Physical and Chemical Indicators of Ferrous Amorphous Graphite & Main Uses
Model Fixed Carbon Content Volatile Moisture Acid-Soluble Iron Weight of Screen Residue Main Uses
WT99.99-45 ≥ 99.99% ≤ 0.2% ≤ 0.005% ≤ 15% Battery and special carbon raw materials
WT99.99-75
WT99.9-45 ≥ 99.9% ≤ 0.2% ≤ 0.005% ≤ 15%
WT99.9-75
WT99-45 ≥ 99% ≤ 0.8% ≤ 1.0% ≤ 0.15% ≤ 15% Pencil, battery, electrode, graphite emulsion and graphite bearing ingredients, battery carbon rod raw materials
WT99-75
WT98-45 ≥ 98% ≤ 1.0% ≤ 1.0% ≤ 0.15% ≤ 15%
WT98-75
WT97-45 ≥ 97% ≤ 1.5% ≤ 1.5% ≤ 0.4% ≤ 15%
WT97-75
WT96-45 ≥ 96% ≤ 1.5% ≤ 1.5% ≤ 0.4% ≤ 15%
WT96-75
WT95-45 ≥ 95% ≤ 2.0% ≤ 1.5% ≤ 0.4% ≤ 15%
WT95-75
WT94-45 ≥ 94% ≤ 2.0% ≤ 1.5% ≤ 0.7% ≤ 15%
WT94-75
WT92-45 ≥ 92% ≤ 2.0% ≤ 2.0% ≤ 0.7% ≤ 10%
WT92-75
WT90-45 ≥ 90% ≤ 2.0% ≤ 2.0% ≤ 0.7% ≤ 10%
WT90-75
WT88-45 ≥ 88% ≤ 3.3% ≤ 2.0% ≤ 0.8% ≤ 10%
WT88-75
WT85-45 ≥ 85% ≤ 3.3% ≤ 2.0% ≤ 0.8% ≤ 10%
WT85-75
WT83-45 ≥ 83% ≤ 3.6% ≤ 2.0% ≤ 0.8% ≤ 10%
WT83-75
WT80-45 ≥ 80% ≤ 3.6% ≤ 2.0% ≤ 0.8% ≤ 10%
WT80-75
WT78-45 ≥ 78% ≤ 3.8% ≤ 2.0% ≤ 1.0% ≤ 10%
WT78-75
WT75-45 ≥ 75% ≤ 3.8% ≤ 2.0% ≤ 1.0% ≤ 10%
WT75-75
Notes:
  • Product model is composed of its classification code, fixed carbon content and fineness (μm).
  • 1 MPa = 10.2 kgf/cm2; 1 W/m.k = 0.86 kcal/cm.h.°C
  • These properties are typical values and not guaranteed.
Table 2: Physical and Chemical Indicators of Ferrous-Free Amorphous Graphite & Main Uses
Model Fixed Carbon Content Volatile Moisture Weight of Screen Residue Main Uses
W90-45 ≥ 90% ≤ 3.0% ≤ 3.0% ≤ 10% Raw materials for casting material, refractory materials, dyes, electrode paste, etc.
W90-75
W88-45 ≥ 88% ≤ 3.2% ≤ 3.0% ≤ 10%
W88-75
W85-45 ≥ 85% ≤ 3.4% ≤ 3.0% ≤ 10%
W85-75
W83-45 ≥ 83% ≤ 3.6% ≤ 3.0% ≤ 10%
W83-75
W80-45 ≥ 80% ≤ 3.6% ≤ 3.0% ≤ 10%
W80-75
W80-150
W78-45 ≥ 78% ≤ 4.0% ≤ 3.0% ≤ 10%
W78-75
W78-150
W75-45 ≥ 75% ≤ 4.0% ≤ 3.0% ≤ 10%
W75-75
W75-150
W70-45 ≥ 70% ≤ 4.2% ≤ 3.0% ≤ 10%
W70-75
W70-150
W65-45 ≥ 65% ≤ 4.2,% ≤ 3.0% ≤ 10%
W65-75
W65-150
W60-45 ≥ 60% ≤ 4.5% ≤ 3.0% ≤ 10%
W60-75
W60-150
W55-45 ≥ 55% ≤ 4.5% ≤ 3.0% ≤ 10%
W55-75
W55-150
W50-45 ≥ 50% ≤ 4.5% ≤ 3.0% ≤ 10%
W50-75
W50-150
Notes:
  • Product model is composed of its classification code, fixed carbon content and fineness (μm).
  • 1 MPa = 10.2 kgf/cm2; 1 W/m.k = 0.86 kcal/cm.h.°C
  • These properties are typical values and not guaranteed.
Fine Machining

Spherical graphite is a kind of graphite products with various fineness and an oval spherical shape. It takes high quality amorphous graphite (aphanitic graphite) as raw materials, and then advanced processing technology is adopted to perform modified treatment on the graphite surface. It is a powder with metallic luster and gray-black or steel gray appearance.

Spherical graphite material features good electrical conductivity and chemical stability, high crystallinity, low cost, high theoretical lithium insertion capacity, high charge/discharge capacity, low charge/discharge potential, etc. It is an important part of the anode (cathode) material for lithium-ion batteries, and is an alternative to anode material for lithium-ion production at home and abroad.

The details of spherical graphite after enlargement
Table 2: Spherical Graphite Technical Indicators
Model Sphericity Fixed Carbon Content Tap Density (g/cm3) Magnetic Substance Content (mg/kg) Ion Content (mg/kg)
SG-Ⅰ-09 ≥ 0.9 ≥ 99.95% ≥ 0.90 ≤ 0.1 ≤ 30
SG-Ⅱ-08 ≥ 0.8 ≥ 99.9% ≥ 0.90 ≤ 0.3 ≤ 50
SG-Ⅲ-06 ≥ 0.6 ≥ 99.0% ≥ 0.75 ≤ 0.5 ≤ 70
Notes:
  • Product model is composed of its classification code, grade and sphericity.
  • 1 MPa = 10.2 kgf/cm2; 1 W/m.k = 0.86 kcal/cm.h.°C
  • These properties are typical values and not guaranteed.
Amorphous Graphite Ore

Amorphous graphite (aphanitic graphite) ore is mostly produced in contact metamorphic coal-series metamorphic shale. The ore body is layered, laminar-like, banded and lenticular, and the ore is earthy, soft, friable and slippery, mostly mined underground, such as Lutang Graphite Ore in China and Bangshi Graphite Ore in Jilini Province, China.

Amorphous graphite ore features small ore body thickness, complex morphology, soft texture and poor stability of roof-to-floor surrounding rocks. Besides, it has small expected surge water in the mining tunnel, and moderate deposit engineering geological and hydrogeological conditions. As a result, flat tunnels and inclined shafts are generally adopted for development, and slicing and caving method is used for mining.

The earthmover is pouring graphite blocks into the truck.