[Industrial Silicon] Green Production Process for Industrial Silicon Based on YT Metal Film

In response to industry challenges such as low reliability of environmental protection facilities, high energy consumption, and difficulty in ensuring the quality of microsilica powder in industrial silicon production, Chengdu Yitai Technology has developed an industrial silicon production process centered on high-temperature metal membranes and membrane separation technology. This technology establishes a deeply integrated system that seamlessly links “environmental protection energy islands” with electric furnace operations, achieving flue-gas treatment that exceeds national ultra-low emission standards. Moreover, intelligent collaborative control significantly enhances production efficiency, leading to its inclusion in multiple national and provincial lists of recommended advanced technologies.

[Core Technological Advantage: A Universal Gene for All Solutions]

All Yitai Technology solutions are underpinned by the following core technologies, providing comprehensive assurance to maximize customer benefits:

1. High-Temperature Metal Membranes and Membrane Separation Technology for Industrial Silicon

• Technical Features: In response to the ultrafine nature of industrial silicon fumes—approximately 80% with particle sizes ≤1 μm—and their inherent charge, a specialized metal membrane has been developed with pore sizes precisely matched to the dust particle size distribution. Leveraging the metal membrane’s outstanding electrical conductivity, this design effectively addresses the challenge of electrostatic adhesion, thereby facilitating dust detachment and settling.
• Core Advantages: Outstanding high-temperature resistance (withstanding 450°C for extended periods) without the need for cold-air protection, fundamentally eliminating the risk of “bag burnout” associated with conventional fabric filters and achieving PM < 1 mg/Nm³ stable low emissions.

2. Lushan Wind AI Intelligent Collaborative Joint Control Technology

• Technical Features: Leveraging large-scale vision models and AI algorithms, a one-to-one serial collaborative relationship is established among the electric furnace, the eco-friendly energy island, and the fans. This enables real-time monitoring of furnace condition changes and intelligent control of fan power as well as the injection rates of desulfurization and denitrification agents.
• Core Advantage: A shift has been achieved from “passive adaptation” to “proactive control.” By eliminating the cold-air protection system, furnace conditions can be directly regulated using a single main fan, thereby effectively reducing energy consumption in electric-arc furnace smelting. Increase the effective conversion rate η of silicon ore , reducing reliance on human expertise and manual operations, thereby significantly enhancing production stability.

3. Integrated Dust-and-Nitrate Process Equipment Technology

• Technical features: High-temperature dust removal and SCR denitrification are integrated into a single unit, employing a zoned design that prioritizes dust removal before denitrification. The use of a metallic-membrane dust collector creates a clean operating environment for the SCR catalyst, thereby achieving NOx ≤ 40 mg/Nm ³。
• Core Advantages: Effectively prevents clogging of catalyst pores by microsilica powder, ensuring the long-term stable operation of the denitrification system. The integrated design reduces the footprint and pipeline heat loss, while lowering system resistance and O&M costs.

4. High-Efficiency Dry Desulfurization Technology

• Technical features: A calcium- or sodium-based desulfurizing agent is used to carry out a fully dry desulfurization reaction within an optimal high-temperature range, with precise control over the reaction temperature and the dosage of the desulfurizing agent.
• Core advantages: The system generates no wastewater, thereby eliminating the secondary pollution and corrosion issues associated with wet flue gas desulfurization. Desulfurizing agent consumption is low, and emission concentrations remain stable at SO ₂ ≤30 mg/Nm³ 。

5. Two-Stage Stepwise Heat Recovery Technology

• Technical Features: In accordance with the temperature requirements of the environmentally friendly process, a two-stage waste heat boiler is employed. The first stage focuses on high-temperature heat recovery, while the second stage balances process cooling with advanced heat utilization.
• Core Advantages: This solution ensures that the environmental protection equipment operates within the optimal temperature range while achieving deep recovery of flue gas waste heat. Compared with conventional processes, it improves thermal energy recovery efficiency by approximately 20%, significantly increases waste heat-based power generation, and reduces production electricity costs.

[Customized Solutions: Meeting Diverse Operating Condition Requirements]

To meet customers’ varying requirements regarding microsilica quality, site conditions, and project characteristics, we offer three differentiated process solutions:

Option 1: High-Temperature Desulfurization All-Dry Process

(Two-stage waste heat recovery + high-temperature desulfurization/dust and sulfur removal in a fully dry process + AI-powered intelligent collaborative control)

1. Project Overview

This scheme employs an all-dry process route, with desulfurization prioritized in the high-temperature section, followed by integrated dust–sulfur treatment. The process flow is compact and particularly well suited for new or retrofitted projects that have modest requirements for microsilica powder quality and place a strong emphasis on system stability and ultra-low environmental emissions.

2. Advantages of the Plan

• Strong process stability: By fully leveraging the high-temperature resistance of metal films, the system operates safely and reliably, adapting to fluctuations in operating conditions.
• Excellent environmental performance: The all-dry process generates no wastewater, and its emission performance exceeds the national ultra-low emission standards.
• Low operational and maintenance costs: The system exhibits low total resistance (<4.5 kPa), enabling optimized operating power for the main fan and significantly reducing electricity consumption.

3. Applicable Scenarios

Suitable for projects that collect ordinary microsilica powder, and ideal for operating conditions that prioritize ultra-low environmental emissions and system stability.

Option 2: Low-Temperature Desulfurization All-Dry Process

(Two-stage waste heat recovery + integrated dust-sulfur removal/low-temperature desulfurization dry process + AI-powered intelligent collaborative control)

1. Project Overview

This scheme optimizes the placement of the desulfurization stage by adopting a “dust removal and denitrification first, followed by low-temperature desulfurization” process. It is designed to address the issue of microsilica powder being contaminated by sulfides, specifically for capturing high-quality microsilica powder and thereby significantly enhancing the economic value of by-products.

2. Advantages of the Plan

• High-quality by-products: Post‑treatment low‑temperature desulfurization effectively prevents the desulfurizing agent from mixing with microsilica powder, thereby ensuring high purity and superior quality of the collected microsilica powder.
• No secondary pollution: It retains the characteristics of an all-dry process, with zero wastewater discharge; the filter media are recyclable, aligning with the principles of green circularity.
• Area Optimization: Compact layout, ideal for projects with limited site space.

3. Applicable Scenarios

Suitable for projects with stringent requirements for microsilica quality that aim to enhance the economic value of by-products.

Option 3: Integrated Dust and Nitrogen Oxide Treatment + Wet Desulfurization Process

(Two-stage waste heat recovery + integrated dust–sulfur removal + wet desulfurization + AI-powered collaborative control)

1. Project Overview

For owners with existing wet flue-gas desulfurization infrastructure or specific environmental protection requirements, this solution integrates high-efficiency dust–sulfur integrated equipment with proven wet desulfurization technology, thereby meeting both the need for high-quality microsilica powder collection and thorough desulfurization.

2. Advantages of the Plan

• Mature desulfurization technology: Wet desulfurization technology is highly mature, operates with excellent reliability, and is well suited to specific operating conditions.
• Economic advantages: Optimized catalyst loading and appropriate control of initial investment costs.
• Balancing Quality and Emissions: This also achieves the separation of microsilica powder from desulfurization byproducts, thereby safeguarding the quality of the microsilica powder while ensuring compliance with emission standards.

3. Applicable Scenarios

Applicable to projects that traditionally use wet desulfurization processes or involve the retrofitting of existing wet desulfurization facilities.

[Case Brief]

     Hongyuan Green Energy Industrial Silicon Eco-Friendly Energy Island Project

1. Project Overview

• Project Name: Hongyuan Green Energy (2 × 33 MVA) Industrial Silicon Electric Furnace Environmental Protection Energy Island Project
• Project Scale: A total of four 33 MVA industrial silicon electric furnaces across Phase I and Phase II.
• Commissioning Dates: Phase I commissioned in December 2023, and Phase II commissioned in December 2024.
• Application Process: Industrial Silicon Production Process and Equipment Based on YT Metal Film

2. Operational Performance
         Since commissioning, the system has successfully withstood extreme operating conditions—including electric furnace baking, waste-heat boiler boiling-out, material collapse, and flame penetration—and achieved successful first-time startup. The system has demonstrated exceptional stability, having operated continuously and reliably to date: 21 months for Phase I and 8 months for Phase II—without a single shutdown attributable to environmental protection or energy-island-related issues. The equipment’s operational reliability has earned high praise from the owner.

3. Core Operational Data (Based on 21 Months of Actual Measurement in Phase I)

• Excellent environmental emission performance:
  • Dust emission concentration <1 mg/Nm³
  • SO₂ emission concentration <30 mg/Nm³
  • NOx emission concentration <40 mg/Nm³
  • All performance indicators significantly exceed the national ultra-low emission standards, leaving ample environmental capacity for the enterprise.
• Significant increase in production capacity:
  • The average daily output per furnace is approximately 63 tonnes (with a peak of 73 tonnes), placing the production capacity at a relatively high level within the industry.
  • The production of microsilica powder is less than 300 kg per ton of silicon, effectively reducing the burden of by-product handling and increasing the silicon ore conversion rate.
• Appropriate control of energy and material consumption:
  • The specific electricity consumption for electric-furnace smelting is 9,500–10,500 kWh per ton of silicon (excluding waste-heat power generation), which is at the lower end of the industry.
  • The system’s total resistance is less than 4.5 kPa, and the main fan’s power consumption is only about 880 kWh/h, resulting in low operating energy consumption.

4. Comprehensive Benefit Analysis

• Economic Benefits: According to calculations, each individual system under this project is expected to generate annual efficiency gains of approximately RMB 11 million, with potential additional revenue of about RMB 3.67 million per year, equivalent to an incremental revenue of roughly RMB 500 per ton of silicon. These benefits primarily stem from reduced energy consumption and increased production in the electric furnaces, enhanced efficiency through waste-heat recovery for power generation, and lower operating costs in the environmental protection island.
• Social Benefits: The project annually saves approximately 12,810 tonnes of standard coal, reduces CO₂ emissions by about 31,614 tonnes, and cuts PM emissions by roughly 58 tonnes, thereby achieving a win-win outcome that balances economic and environmental benefits.