**Abstract**
This paper presents the practical experience of replacing the graphite flow tank with a copper water-jacketed tank in the flash furnace. By analyzing the causes of slag flow tank failure, this study aims to enhance production efficiency and reduce operational costs. The transformation was implemented to address the increasing wear and tear on the original system due to rising slag volume and temperature.
**Introduction**
In recent years, Guixi Smelting Plant has continuously improved its production capacity through technological advancements. The project design capacity has been upgraded from 93,000 to 200,000 tons. However, during this expansion, certain weak points in the production process became evident. One major issue was the frequent loss of the slag discharge trough in the flash furnace, which disrupted operations and affected overall performance. To tackle this problem, the plant introduced real-time temperature monitoring and automated control systems for the main equipment motors.
The instruments used in the system transmit standard 4-20 mA current signals or pulse signals. These signals are isolated and converted into 15 V voltage signals by a signal conversion circuit. The microcontroller processes these signals in real time and sends control commands to the electromagnetic valves and motor-driven devices on the production line.
The real-time measurement and control system is based on the high-quality and cost-effective MCS48 series 8031 microcontroller. It includes analog input/output, switch input/output circuits, and other signal driving components. This system ensures accurate temperature monitoring, flow weight collection, automatic control of solenoid valves, and system failure alarms.
The system also controls the ratio of water phase, oil phase, and foaming agent flow using flow meters, a microcomputer regulator, and variable-speed motors. Isolated flow signals are sent to the regulator, which adjusts the speed of each motor based on the required ratios, enabling automatic flow control.
In 1996, a detailed analysis was conducted on the flow loss issue, leading to a successful transformation that largely resolved the problem.
**Loss Cause Analysis**
During the operation of the flash furnace, slag is transferred between two graphite flow tanks. A temperature control system, including sensors, transmitters, and a microcomputer controller, regulates the temperature by controlling steam or cooling water via solenoid valves. The isolated temperature signal is processed by the microcontroller, which decides whether to heat or cool the material accordingly.
On-site data shows that key production parameters are displayed on the operation console, guiding operators and supervisors in managing the production process.
**Conclusion**
After many years of operation, the system ensures the safety of emulsion explosive production, maintains the stability of product quality, and reduces labor intensity. It also offers reliable performance, ease of use, and simple maintenance.
**Slag Flow Tank Failure Causes**
The main cause of the flow tank loss in the flash furnace is the high temperature of the slag. As production increases, so does the amount of slag. After copper output reached 140,000 tons, the loss of the slag flow tank became more apparent, especially with the introduction of high-temperature, high-volume smelting technology.
The slag amount increased from 29,000 to 90,000 tons, and the feeding amount was calculated at 160,000 tons of ice copper and 24% concentrate. This led to increased scouring of the flow tank, requiring more frequent replacements and affecting normal production.
**Transformation Implementation**
To address these issues, the flow tank was redesigned with a more durable structure and made from copper, which offers better thermal conductivity and corrosion resistance. The new copper water-jacketed tank is more efficient, longer-lasting, and easier to maintain.
**Design Concepts**
The primary focus was on improving the temperature resistance of the flow cell. The new design allows it to withstand high temperatures without burning or leaking, ensuring smooth production. Copper was chosen as the material due to its excellent thermal conductivity and durability.
For cooling, water was selected over compressed air because it provides better heat transfer. While compressed air is safer, it lacks the cooling efficiency of water. With proper design and regular maintenance, water-cooled systems can be both safe and effective.
The internal wall of the flow tank is thicker than the outer wall to protect the copper tubes and extend their service life. A copper water-jacketed trough with embedded pipes was designed for easy installation and maintenance.
**Post-Transformation Features**
After the transformation, the slag flow tank exhibits several advantages:
- **High Temperature Resistance**: The copper flow trough efficiently removes heat from the slag using circulating cooling water, preventing rapid temperature changes.
- **Erosion Resistance**: The smooth inner surface promotes quick formation of a protective slag layer, reducing erosion.
- **Durability**: The tank experiences fewer failures and has a longer service life, ensuring stable production.
- **Cost-Effective**: The new design is easier to manufacture and replace, reducing both production costs and labor intensity.
**Operational Benefits**
The implementation of the copper water-jacketed tank significantly improved production efficiency. Before the transformation, the system was affected once a week, causing a 10% reduction in processing capacity. In severe cases, the flash furnace had to be shut down, leading to equipment damage. After the upgrade, production remained uninterrupted.
The cost savings were substantial. The daily consumption cost before the transformation was around 3,290.06 yuan. After the change, the annual cost savings reached approximately 160,000 yuan.
**Conclusion**
As the slag volume and temperature continue to rise, the replacement of the graphite flow tank with a copper water-jacketed one is essential for maintaining production efficiency and meeting the demands of high-temperature smelting. This transformation not only reduces costs but also solves real-world production challenges and supports the development of Guixi Smelting Plant.
**Received Date: 1999**
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