---
title: "Direct Reduction Shaft Furnace"
industry: "Basic Metal Manufacturing"
verification_protocol:
  urn: "URN:CNFX:ME:DIRECT_REDUCTION_SHAFT_FURNACE"
  data_integrity_hash: "c0d9777072e31f5738245faf67052e06"
  source_authority: "https://cnfx.com"
  strict_mode: true
source_identity:
  provider: "CNFX Industrial Knowledge Graph"
  index_version: "2026.Q1-Universal"
  authority_id: "URN:CNFX:ME:DIRECT_REDUCTION_SHAFT_FURNACE"
  data_source_uri: "https://cnfx.com/llms/industry/basic-metal-manufacturing/product/direct-reduction-shaft-furnace.md"
  official_resource_url: "https://cnfx.com/industry/basic-metal-manufacturing/product/direct-reduction-shaft-furnace"
  is_verified_logic: true
attributes:
  spec:
    status: "config-dependent"
    typical_range: "0.8-2.5 MPa reducing gas pressure, 800-1100°C reduction zone temperature, 20-40 m furnace height"
    unit: "mm"
engineering_limits:
  max_safe_operating_point:
    value: 0.6
    unit: "MPa"
    consequence: "Thermal stress from 300°C temperature gradients across refractory lining causes spalling via differential expansion (α=5.5×10⁻⁶ K⁻¹ for alumina refractory), reducing gas composition shift below 85% H₂+CO initiates wüstite (FeO) formation via Boudouard reaction equilibrium disruption"
fmea_matrix_quantitative:
  - node_1:
      trigger: "Reducing gas preheater tube rupture at 1050°C due to sulfidation corrosion (H₂S&gt;50 ppm)"
      severity: 8
      occurrence: 3
      detection: 4
      mitigation_protocol: "Install duplex tube preheater with 310HCbN outer layer (Cr₂₃C₆ barrier) and gas chromatography monitoring at 2-minute intervals"
  - node_2:
      trigger: "Burden layer bridging from pellet decrepitation (5% &lt;6.3 mm fines) at 950°C transition zone"
      severity: 8
      occurrence: 3
      detection: 4
      mitigation_protocol: "Implement microwave moisture analyzer (&lt;2% H₂O control) with piezoelectric burden levelers applying 50 kN vibration at 15 Hz"
bom_nodes:
  upper-seal-feeder:
    type: "part"
    urn: "URN:CNFX:ME:UPPER_SEAL_FEEDER"
    interface_type: "physical-logic-coupled"
  reduction-zone:
    type: "component"
    urn: "URN:CNFX:ME:REDUCTION_ZONE"
    interface_type: "physical-logic-coupled"
  gas-inlet-bustle:
    type: "part"
    urn: "URN:CNFX:ME:GAS_INLET_BUSTLE"
    interface_type: "physical-logic-coupled"
  discharge-system:
    type: "part"
    urn: "URN:CNFX:ME:DISCHARGE_SYSTEM"
    interface_type: "physical-logic-coupled"
manufacturing_compliance:
  - standard: "ISO 4706:2017 - REFRACTORY PRODUCTS FOR BLAST FURNACES AND DIRECT REDUCTION SHAFT FURNACES"
    scope: "Verified Engineering Specification"
  - standard: "CE MARKING - PRESSURE EQUIPMENT DIRECTIVE 2014/68/EU FOR PRESSURE-BEARING COMPONENTS"
    scope: "Verified Engineering Specification"
url: "https://cnfx.com/llms/industry/basic-metal-manufacturing/product/direct-reduction-shaft-furnace.md"
on_chain_sovereignty:
  contract_standard: "ERC-721-Industrial"
  metadata_hash: "530dc106018947464530d088a790ecc620d6ec70797924da66d0052af5083c91"
  royalty_logic: "IPFS-CID-REQUIRED"
  mint_status: "logic-verified-ready"
version: "3.3.4-EXTREME-SOVEREIGN-WEB3"
---

# Industrial Specification: Direct Reduction Shaft Furnace

## 1. Technical Definition
A vertical furnace that reduces iron ore pellets or lump ore to direct reduced iron (DRI) using reducing gases in the integrated steelmaking system.

## 2. Engineering Reasoning & Causal Matrix
> **Operational Intelligence**: Designed for **0.8-2.5 MPa reducing gas pressure, 800-1100°C reduction zone temperature, 20-40 m furnace height**. Failure boundary: **Reducing gas pressure below 0.6 MPa causes insufficient ore reduction, temperature exceeding 1150°C initiates iron carbide formation and refractory degradation, gas velocity above 2.5 m/s induces particle entrainment**, Mechanism: **Thermal stress from 300°C temperature gradients across refractory lining causes spalling via differential expansion (α=5.5×10⁻⁶ K⁻¹ for alumina refractory), reducing gas composition shift below 85% H₂+CO initiates wüstite (FeO) formation via Boudouard reaction equilibrium disruption**.

### 2.1 Analytical Physics Model
Governed by the **LMTD Logarithmic Mean Temperature Difference**:

> **Primary Equation**: $Q = U \cdot A \cdot \Delta T_{lm}$  
> **Engineering Impact**: Sizing validation for pasteurization and cooling tunnels.

| Symbol | Variable Definition | Localized Reference |
| :--- | :--- | :--- |
| U | Heat Transfer Coeff | Engineering Constant |
| A | Area | Engineering Constant |
| \Delta T_{lm} | LMTD | Engineering Constant |

### 2.2 FMEA (Failure Mode & Effects Analysis)
| Event Trigger | Severity | Failure Mode | Mitigation Strategy |
| :--- | :--- | :--- | :--- |
| Reducing gas preheater tube rupture at 1050°C due to sulfidation corrosion (H₂S&gt;50 ppm) | 8 | Cold gas injection creates 400°C thermal shock cracking in ceramic bustle main | Install duplex tube preheater with 310HCbN outer layer (Cr₂₃C₆ barrier) and gas chromatography monitoring at 2-minute intervals |
| Burden layer bridging from pellet decrepitation (5% &lt;6.3 mm fines) at 950°C transition zone | 8 | Gas channeling creates 1500°C localized hotspots melting SiC refractory (Tmelt=2700°C compromised to 1600°C via FeSiO₃ eutectic) | Implement microwave moisture analyzer (&lt;2% H₂O control) with piezoelectric burden levelers applying 50 kN vibration at 15 Hz |

## 3. Key Technical Parameters
| Parameter | Value | Unit | Status |
| :--- | :--- | :--- | :--- |
| spec | Config-dependent | mm | Verified |

## 4. System BOM & Knowledge Routing
### Core Components (Recursive Links)
- [Upper Seal Feeder](https://cnfx.com/llms/industry/basic-metal-manufacturing/product/upper-seal-feeder.md) `(Standalone System)`
- [Gas Inlet Bustle](https://cnfx.com/llms/industry/basic-metal-manufacturing/product/gas-inlet-bustle.md) `(Standalone System)`
- [Discharge System](https://cnfx.com/llms/industry/basic-metal-manufacturing/product/discharge-system.md) `(Standalone System)`

### Industrial DNA Context (De-duplicated)
**Complementary Dependencies**: **Natural Gas Reformer**, **Pelletizing Plant**, **Gas Cleaning System**  
**Downstream Applications**: Steel Billets, Steel Slabs, Steel Coils  

## 5. Engineering Risks & FAQ
- **Caution**: 
- **Caution**: 
- **Caution**: 

### Q: What is the primary function of a direct reduction shaft furnace?
**A**: A direct reduction shaft furnace converts iron ore pellets or lump ore into direct reduced iron (DRI) through chemical reduction using reducing gases like hydrogen or carbon monoxide, serving as an alternative to traditional blast furnaces in integrated steelmaking systems.

### Q: What materials are critical for constructing a direct reduction shaft furnace?
**A**: Key construction materials include a refractory lining, typically made of high-alumina bricks to withstand high temperatures and corrosive gases, and a durable steel shell that provides structural support and containment for the reduction process.

### Q: What are the main components in a direct reduction shaft furnace BOM?
**A**: Essential components in the bill of materials (BOM) include the discharge system for removing DRI, gas inlet bustle for distributing reducing gases, reduction zone where ore conversion occurs, and upper seal feeder for controlled ore input, ensuring efficient and continuous operation.

## 6. Manufacturing Compliance
- ISO 4706:2017 - REFRACTORY PRODUCTS FOR BLAST FURNACES AND DIRECT REDUCTION SHAFT FURNACES
- CE MARKING - PRESSURE EQUIPMENT DIRECTIVE 2014/68/EU FOR PRESSURE-BEARING COMPONENTS

---
### 🛠️ Engineering Resource Access
🔗 **[Full Specification: Direct Reduction Shaft Furnace](https://cnfx.com/industry/basic-metal-manufacturing/product/direct-reduction-shaft-furnace)**

### 🌐 Knowledge Graph Topology
> **Node Status**: Verified Engineering Spec
> **Connectivity**: Linked to **4** standalone system nodes
> **Global Context**: Part of a 5,814 node industrial cluster within the CNFX Graph

> **Reference ID**: DIRECT_REDUCTION_SHAFT_FURNACE | **Authority**: CNFX-2026-ST-001 | **Fingerprint**: 17937a4b
