Project Overview
At Weifang Special Steel in Shandong Province, China, a 4000KVA hot slag holding furnace was engineered to turn molten steel slag directly into mineral wool. The installation converts a waste stream from steelmaking into a saleable insulation product, and it has become one of the reference projects that define Shaanxi Chengda Industrial Furnace Manufacturing Co., Ltd. as a full-scope supplier of molten slag heat-holding and slag-to-wool equipment.
Scope of supply covered process design, furnace body and shell fabrication, electrode and power system, thermal insulation lining, automation and instrumentation, site foundation modification, erection, cold and hot testing, and commissioning support.
The Challenge
- Molten slag arrives intermittently from the steelmaking shop and must be kept within a narrow temperature window before fiberization.
- Temperature loss in the transfer and holding stage causes poor fiber quality, higher shot content and unstable wool output.
- The equipment had to be integrated into an existing plant, with limited space and a live steelmaking operation next to the construction area.
- The site is a high-dust, high-vibration environment, demanding robust refractory lining and reliable electrical design.
Technical Solution
The core unit is a 4000KVA molten slag holding furnace. Slag is charged directly in the liquid state, held and homogenized, then delivered at a controlled temperature and flow rate to the wool-spinning unit. This molten-charge route removes the need to re-melt cold slag, cutting fuel consumption and process steps.
| Item | Specification |
|---|---|
| Project | Weifang Special Steel hot slag heating furnace |
| Furnace rating | 4000 KVA |
| Application | Molten steel slag holding and heating for mineral wool production |
| Charge condition | Liquid slag, direct molten charging |
| Key subsystems | Furnace shell and water-cooled elements, electrode system, insulation lining, temperature control, automation |
| Deliverables | Design, fabrication, foundation modification, erection, commissioning |
Execution Timeline
- Foundation modification – existing plant foundations reworked to suit furnace loads and slag runner routing.
- Civil and steel structure works – base construction and support frames completed on site.
- Site installation – furnace body, shell, electrodes and auxiliary systems erected and aligned.
- Installation progress review – stage inspections of piping, insulation and electrical routing.
- Cold and hot commissioning – heating-up curve, molten slag trials, and operating parameters verified on site.
- Production run – continuous molten slag processing with wool line in operation.
Results
- Molten slag is now processed directly into mineral wool, turning a disposal cost into a product line revenue stream.
- Stable holding temperature secures consistent fiber quality and reduces shot content in the finished wool.
- The plant runs a simpler route with fewer handling steps and lower re-melting energy demand.
- Commissioning was completed with the steelmaking operation running, without interrupting upstream production.
Related Molten Slag Projects
The same holding-furnace platform has been delivered to a series of domestic and overseas references, including the Yuxi hot slag holding furnace in Yunnan, the India slag wool holding furnace, the Hancheng blast furnace hot slag holding furnace, and the 6600KVA slag furnace for Shanxi Dongfang Group.
Why Choose Shaanxi Chengda
Shaanxi Chengda Industrial Furnace Manufacturing Co., Ltd. is a source manufacturer of metallurgical electric furnaces, supplying ferroalloy submerged arc furnaces, ladle refining furnaces, steelmaking electric arc furnaces, DC arc furnaces, corundum furnaces, solid waste slag wool equipment and industrial heat treatment lines. Every project is delivered with in-house design, fabrication, erection and commissioning under one engineering quality system — one accountable partner from layout drawing to first tap.