Sino Industrial Refractory Solution for PT. VALE in Indonesia:

PT. VALE Indonesia TBK (hereinafter referred to as "PT. VALE") is one of the world’s leading nickel producers, operating large-scale ferronickel smelting projects in Indonesia. As the core equipment of the RKEF (Rotary Kiln-Electric Furnace) process, the ferronickel furnace’s lining directly determines the stability of production continuity, operational safety, and economic benefits. Faced with severe challenges such as short service life, frequent maintenance, and production interruptions caused by lining erosion, PT. VALE sought a professional refractory solution partner. Sino Industrial, with its rich experience in metallurgical refractory engineering and advanced integrated design capabilities, successfully solved the long-standing ferronickel furnace lining problems for PT. VALE, helping to improve production efficiency and reduce operational costs.

1. Background of PT. VALE’s Ferronickel Furnace Lining Challenges
PT. VALE’s ferronickel smelting process mainly adopts the RKEF technology, with the ferronickel furnace being a large-scale electric furnace with a capacity exceeding 33MVA. The plant processes saprolite nickel ore, including West Block Ore (WBO) with high silica/magnesia content, which makes the smelting slag more acidic and higher in viscosity, significantly increasing the erosion of the furnace lining. Before cooperating with Sino Industrial, the ferronickel furnace lining of PT. VALE suffered from the following prominent problems:
- Severe Erosion and Short Service Life: The furnace lining was frequently eroded by high-temperature molten slag (above 1600℃), molten ferronickel, and chemical reactions. The slag line area, furnace bottom, and tapping/slag tapping ports were the most severely damaged parts. The average service life of the lining was less than 6 months, far below the industry’s advanced level, leading to frequent shutdowns for maintenance.
- Poor Structural Stability: The traditional lining design lacked overall consideration, with mismatched refractory materials and unreasonable setting of expansion joints and elastic layers. Under the combined action of high temperature, pressure, and thermal stress, the lining was prone to cracks, spalling, and even molten iron penetration. In severe cases, it caused furnace shell deformation and local overheating, posing serious safety hazards.
- High Maintenance Cost and Low Production Efficiency: Frequent shutdowns for lining replacement not only consumed a large amount of refractory materials and labor costs but also seriously affected the continuity of smelting production. The frequent maintenance also led to increased energy consumption and reduced nickel extraction efficiency, bringing significant economic losses to PT. VALE.

- Material Mismatch: The previously used refractory materials could not adapt to the characteristics of PT. VALE’s smelting process, such as high slag viscosity and strong chemical corrosion. For example, the early use of carbon bricks or magnesia bricks for the furnace bottom resulted in frequent burnout, while the refractory mortar and mixes failed to provide effective protection for the furnace roof and wall.
2. Sino Industrial’s Integrated Refractory Design Solution
After in-depth on-site investigation, Sino Industrial fully grasped the smelting process parameters, ore characteristics, and lining damage mechanism of PT. VALE’s ferronickel furnace. Based on the principles of "adaptive design, material optimization, structural improvement, and full-cycle protection", we formulated a targeted integrated refractory solution, breaking the traditional single-component replacement mode and realizing the organic combination of design, material selection, construction, and operation maintenance.
2.1 Overall Design Concept: Adapt to Process Characteristics and Achieve Full-Cycle Stability
Combined with PT. VALE’s use of WBO ore with high silica/magnesia content and the technological characteristics of the RKEF process, Sino Industrial optimized the overall structure of the ferronickel furnace lining. The design fully considered the parameters such as furnace shell size, furnace chamber depth, and electrode layout, and determined the reasonable thickness of the furnace bottom (2.1m) and furnace wall (1.2m), which not only met the production needs but also avoided the waste of materials caused by excessive thickness. At the same time, the design focused on solving the key problems of erosion, spalling, and penetration, and adopted a hierarchical structure design for different parts of the furnace lining to achieve targeted protection.

2.2 Key Component Design and Material Optimization
According to the different service environments of each part of the ferronickel furnace, Sino Industrial selected and customized high-performance refractory materials, and optimized the structural design to improve the erosion resistance and stability of the lining.
2.2.1 Furnace Bottom: Seamless Integrated Ramming Design
Aiming at the problem of molten iron penetration and pressure damage at the furnace bottom, Sino Industrial abandoned the traditional brick-laying structure and adopted a magnesium-based ramming material for integral seamless ramming. The ramming material was customized with high-purity magnesia as the main component, adding special additives to improve its density and high-temperature strength. The construction adopted layered ramming technology, with each layer’s compacted thickness controlled at 160-200mm, and the density after compaction reached more than 2.8g/cm³. After sintering, a dense and firm ceramic layer was formed, effectively preventing molten iron from penetrating into the lining through gaps. At the same time, a 300mm thick elastic layer was designed between the furnace bottom and the furnace shell to balance the pressure and thermal expansion stress, avoiding furnace shell cracking caused by excessive stress.
2.2.2 Furnace Wall: Hierarchical Protection and Slag Line Enhancement
The furnace wall was designed with a three-layer structure: insulation layer, transition layer, and working layer, to achieve the balance of insulation, heat resistance, and erosion resistance. The slag line area, which is most severely eroded by molten slag, adopted high-purity magnesia bricks (97% magnesia content) with strong corrosion resistance and good slag hanging performance. During the smelting process, a stable slag layer could be formed on the surface of the bricks to reduce direct erosion of the refractory material by molten slag. Above the slag line, high-alumina bricks with excellent insulation performance were used as the insulation layer to reduce heat loss and energy consumption. The joint between the bricks was filled with high-temperature refractory mortar, and expansion paper was laid between the bricks according to the expansion coefficient to eliminate thermal expansion stress and prevent joint cracking.

2.2.3 Tapping/Slag Tapping Ports: Copper Water Jacket Combined with Refractory Protection
The tapping and slag tapping ports are key parts with frequent material flow and severe erosion. Sino Industrial adopted a combination design of copper water jacket and special refractory materials. The copper water jacket was used to ensure stable operation and easy maintenance, with the tapping port depth set at 1.5m, slag tapping port depth at 1.3m, tapping port diameter at 60mm, and slag tapping port diameter at 100mm. 3-4 tapping ports and 2 slag tapping ports were arranged, with a height difference of 700mm between the slag tapping port and the tapping port to avoid molten iron overflow. The inner wall of the ports was lined with high-temperature resistant and erosion-resistant refractory castables, which were integrally cast to ensure no gaps and prevent molten iron and slag from eroding the copper water jacket and furnace shell.
2.2.4 Furnace Roof: Composite Lining System
Referring to the international advanced furnace roof design experience, Sino Industrial developed a composite lining system for the furnace roof, combining high-quality refractory mortar and protective refractory mixes. The system avoided the high cost and complex construction of traditional thrust-suspension roofs, and improved the durability of the furnace roof lining. The refractory materials used for the furnace roof had excellent high-temperature resistance and thermal shock resistance, which could withstand the frequent temperature changes during smelting and reduce the risk of roof spalling and damage.
2.3 Construction Quality Control and Process Optimization
Good design needs reliable construction to realize its value. Sino Industrial sent a professional construction team to PT. VALE’s site, and formulated a strict construction quality control system:
- Before construction, the furnace shell structure was inspected and accepted, including measuring the furnace shell diameter and height, calibrating the furnace center and center line, and ensuring that the welding seams of the furnace shell met the design requirements through UT testing.
- During the construction of the furnace bottom ramming material, layered ramming was adopted, and a flat vibrator was used for uniform vibration. After each layer of ramming, a rake was used to "roughen" the surface to increase the contact area between adjacent layers and form a seamless integral furnace bottom.

- When laying furnace wall bricks, wooden hammers or rubber hammers were used for alignment to avoid damage to the bricks. The joint thickness was strictly controlled within 2mm, and the joint was filled with refractory mortar to ensure full filling. The closing bricks were evenly distributed on both sides of the 90° angle between the tapping port and the slag tapping port, and the processed bricks were guaranteed to be more than half of the original brick width.
- During the construction of the tapping and slag tapping ports, the refractory bricks were pre-laid and trimmed. The refractory mortar prepared with magnesia powder and water glass was used for wet laying, with staggered joints and no through joints, and the brick joint was ≤1mm.
At the same time, Sino Industrial optimized the smelting operation process in combination with the lining design, proposed reasonable slag type control parameters, and adjusted the feeding and temperature rising speed to reduce thermal shock and mechanical impact on the lining, further extending the service life of the lining.
2.4 Full-Cycle After-Sales Service and Maintenance Guidance
To ensure the long-term stable operation of the furnace lining, Sino Industrial provided PT. VALE with full-cycle after-sales service: dispatched professional technical personnel to the site for real-time monitoring of the lining operation status, regularly inspected the lining thickness and damage, and provided timely maintenance suggestions; trained PT. VALE’s operation and maintenance personnel to master the key points of lining daily maintenance and emergency handling; and adjusted the refractory material formula and design scheme according to the changes in smelting parameters and ore characteristics to ensure the adaptability of the solution.
3. Implementation Effect of the Solution
Since the implementation of Sino Industrial’s integrated refractory design solution, PT. VALE’s ferronickel furnace lining has achieved remarkable improvement, completely solving the long-standing problems of short service life and frequent maintenance, and bringing significant economic and safety benefits to the enterprise:
- Significantly Extended Lining Service Life: The average service life of the ferronickel furnace lining has been increased from less than 6 months to more than 36 months, which is 6 times the original service life, and the durability of the lining has been increased by 1.5 times, reaching the advanced level of the industry. Some furnaces have even achieved stable operation for more than 40 months, greatly reducing the frequency of shutdown maintenance.
- Improved Production Continuity and Efficiency: Frequent shutdowns caused by lining damage have been completely eliminated. The annual operation time of the ferronickel furnace has been increased by more than 800 hours, the smelting efficiency has been improved by 15%, and the nickel extraction rate has been increased by 3%-5%. At the same time, the energy consumption per ton of ferronickel has been reduced by 8%, significantly improving the economic benefits of PT. VALE.

- Reduced Maintenance Costs: The number of lining replacements has been reduced from 2-3 times a year to once every 3 years. The consumption of refractory materials has been reduced by 60%, and the labor cost for maintenance has been reduced by 70%. The annual maintenance cost has been saved by more than 2 million US dollars, achieving significant cost reduction and efficiency increase.
- Enhanced Operational Safety: The integrated design and high-performance refractory materials have effectively solved the problems of lining cracking, spalling, and molten iron penetration. The local overheating and deformation of the furnace shell have been eliminated, and the safety risks in the smelting process have been greatly reduced, ensuring the safe and stable operation of the production line.
- Adapted to Process Characteristics: The customized refractory materials and optimized design scheme fully adapt to the characteristics of PT. VALE’s WBO ore smelting, effectively solving the problem of strong slag erosion caused by high silica/magnesia content. The slag viscosity is controlled within a reasonable range, and the separation efficiency of molten metal and slag is improved.
4. Case Summary
The successful cooperation between Sino Industrial and PT. VALE in Indonesia fully demonstrates the core competitiveness of Sino Industrial’s integrated refractory design solution in solving ferronickel furnace lining problems. Unlike the traditional single material replacement or partial maintenance mode, Sino Industrial starts from the root cause of lining damage, integrates design, material selection, construction, and maintenance, and formulates a solution that is fully adapted to the actual production conditions of PT. VALE. This not only solves the long-standing technical problems of PT. VALE but also helps the enterprise improve production efficiency, reduce costs, and enhance core competitiveness.
As a professional refractory solution provider, Sino Industrial will continue to rely on advanced technology and rich engineering experience to provide customized, high-efficiency, and energy-saving refractory solutions for global metallurgical enterprises, helping customers achieve sustainable and high-quality development in the field of ferronickel smelting and other high-temperature industries.