Carbon Agglomerate Production via Solid-Phase Sintering
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Solution Overview
Problem
Conventional methods struggle to produce high-strength carbon agglomerate using carbonaceous raw materials with poor softening and melting properties, particularly for use in blast furnaces, due to the reliance on liquid-phase sintering phenomena, which limits the usage of such materials.
Innovation Solution
A method involving solid-phase sintering-like phenomenon is employed by heat-treating and pulverizing carbonaceous raw materials with specific volatile content and particle size, followed by pressure molding at controlled temperatures and pressures to bond the particles, forming high-strength carbon agglomerate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If liquid-phase sintering is used to bond carbonaceous powder particles, then carbon agglomerate can be produced, but high strength sufficient for blast furnace use cannot be obtained when using carbonaceous raw materials with poor softening and melting properties
Solution Approach 1:
The invention changes the sintering mechanism from liquid-phase to solid-phase by controlling the temperature parameter. Specifically, the carbonaceous raw material is heated to 500°C or higher but below the softening point of caking coal, maintaining a solid state throughout the sintering process. This parameter change enables the use of non-caking coal and biomass with poor softening properties while still achieving high-strength carbon agglomerate suitable for blast furnace use.
Solution Approach 2:
The invention replaces the chemical bonding mechanism of liquid-phase sintering with a mechanical interlocking mechanism in solid-phase sintering. The angular particles of carbonaceous raw material are heated to enhance their mechanical interlocking capability, allowing them to bond without requiring liquid binders or softening properties. This substitution enables the use of diverse carbonaceous materials including those with poor caking properties.
2Strength
If caking coal is used as raw material, then high-strength coke can be produced, but depletion of suitable caking coal occurs and alternative materials cannot be effectively utilized
Solution Approach 1:
The invention changes the fundamental sintering parameter from liquid-phase (requiring softening and melting) to solid-phase (relying on mechanical interlocking and friction). This enables the substitution of depleted caking coal resources with alternative carbonaceous materials such as non-caking coal and biomass, thereby maintaining coke production capacity despite resource depletion.
Solution Approach 2:
The solid-phase sintering method creates a universal process that can handle multiple types of carbonaceous raw materials with different properties. Unlike liquid-phase sintering that requires specific caking properties, the solid-phase method works with diverse materials including non-caking coal, biomass, and other carbonaceous substances, making the process universally applicable to various feedstocks.
3Strength
If carbonaceous powder with small particle size is used for agglomeration, then particle bonding is improved, but excessive particle size reduction decreases plasticity in liquid-phase sintering
Solution Approach 1:
The invention replaces the plasticity-dependent liquid-phase bonding mechanism with a mechanical interlocking mechanism suitable for solid-phase sintering. Angular particles with small size (0.044 mm or more, preferably 0.01 mm or more) provide sufficient surface area and mechanical interlocking capability without requiring plastic deformation. This substitution eliminates the negative effect of excessive particle size reduction on plasticity while maintaining strong particle bonding.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the production of carbon agglomerate with sufficient strength for blast furnace use, even when using carbonaceous materials with poor softening and melting properties, without relying on liquid-phase components.
Implementation Method 1
the particles of the carbonaceous powder are bonded to each other by a solid-phase sintering phenomenon
Implementation Method 2
a powder preparation process of preparing a carbonaceous powder obtained by heat-treating a carbonaceous raw material
Data Source
Figure 1
AI summary
A method of producing carbon agglomerate is provided, capable of producing carbon agglomerate having high strength capable of withstanding use in a blast furnace even when a usage amount of carbonaceous raw material that has poor softening and melting property is increased. The method includes: a powder preparation process of preparing a carbonaceous powder obtained by heat treating carbonaceous raw material having a maximum fluidity MF of 5 ddpm or less as measured by a Gieseler plastometer, the carbonaceous powder having a volatile content of 6 wt% D.B. or more and less than 20 wt% D.B. and a maximum particle size of 300 µm or less; and a hot pressing process of pressure molding the carbonaceous powder under a set of conditions including a maximum arrival temperature of 600 °C or more and 1250 °C or less in an oxygen-excluded environment to obtain the carbon agglomerate.