Reduced Iron Agglomerate Manufacturing Process
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Solution Overview
Problem
The existing direct reduction ironmaking process faces challenges in improving the yield of large-grain reduced iron agglomerates, reducing manufacturing time, and minimizing impurity elements like sulfur in the agglomerates.
Innovation Solution
The process involves charging compacts with an iron oxide-containing material and a carbonaceous reducing agent onto a moving-bed heating furnace, where the iron oxide-containing material has a mean particle diameter of 4 to 23 μm and 18% or more of particles are 10 μm or less in mass, facilitating reduction-melting and coalescence, and optionally including a melting-point-adjusting agent to enhance the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ironmaking process is used with general particle size iron oxide material, then the process is simple to operate, but the yield of large-grain reduced iron agglomerates is low and manufacturing time is long
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size parameters of iron oxide-containing material. Specifically, it uses material with mean particle diameter of 10 μm or less and ensures 18% or more of particles are 10 μm or smaller. This parameter optimization enables faster reduction-melting rates and improved coalescence, directly resolving the contradiction between productivity and process complexity.
2Object-affected harmful factors
If coalescence-promoting agent (fluorite) and MgO-containing substance (dolomite ore) are added to adjust slag components, then sulfur content in granular iron is reduced, but the improvement effect becomes saturated and further reduction is difficult
Solution Approach 1:
The patent applies preliminary action by pre-optimizing the particle size distribution of iron oxide-containing material before the reduction process. This preliminary preparation creates optimal conditions for reduction-melting and coalescence, enabling more effective sulfur removal through slag formation without reaching saturation. The pre-adjusted particle size enhances the effectiveness of subsequent sulfur removal actions.
Solution Approach 2:
The patent changes physical parameters (particle size and distribution) rather than continuing to adjust chemical composition. By using iron oxide material with mean particle diameter of 10 μm or less and specific distribution, the process achieves improved sulfur removal efficiency and continued marginal improvement beyond what chemical additives alone can provide.
3Speed
If iron oxide-containing material with smaller particle diameter is used, then reduction-melting rate increases and productivity improves, but particle size control becomes more difficult and manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by establishing specific particle size parameters: mean particle diameter of 10 μm or less, with 18% or more of particles being 10 μm or smaller. These quantified parameters provide clear manufacturing targets that balance reduction-melting speed with manufacturability, resolving the contradiction between speed and ease of manufacture.
Solution Approach 2:
The patent applies partial action by not requiring all particles to be extremely fine, but rather setting a mean diameter of 10 μm or less with a specific distribution (18% or more at 10 μm or smaller). This partial optimization achieves sufficient reduction-melting rate improvement while maintaining reasonable manufacturing ease, avoiding the excessive complexity that would result from requiring all particles to be uniformly ultra-fine.
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 enhances the yield of large-grain reduced iron agglomerates, reduces manufacturing time, and minimizes sulfur content, thereby improving productivity and product quality.
Implementation Method 1
heating the compacts to reduce iron oxide in the compacts with carbonaceous reducing agent
Implementation Method 2
The compacts are heated in the furnace by gas heat transfer and radiant heat with a heating burner
Implementation Method 3
The compacts are heated in the furnace by gas heat transfer and radiant heat with a heating burner
Implementation Method 4
the resulting reduced iron is carburized, melted, and coalesced into agglomerates
Implementation Method 5
the agglomerates are cooled and solidified to provide agglomerative metallic iron
Data Source
AI summary
A process for manufacturing reduced iron agglomerates which comprises introducing starting agglomerates that comprise both an iron oxide-containing material and a carbonaceous reducing agent onto the hearth of a moving-bed heating furnace, and heating the agglomerates to reduce the iron oxide contained in the agglomerates, wherein the iron oxide-containing material contained in the starting agglomerates has a mean particle diameter of 4 to 23 μm and contains at least 18% of particles having diameters of 10 μm or less. By the use of such starting agglomerates, the process attains: an improvement in the yield of reduced iron agglomerates having large particle diameters; a reduction in the manufacturing time, said reduction leading to an enhancement in the productivity; and a remarkable reduction in the content of impurities such as sulfur in the reduced-iron agglomerates.