ENFI is devoted to building efficient, energy-saving, safety and environmental protection modern metallurgy enterprises. With advanced concepts and core proprietary technologies, ENFI is engaged in the engineering design, contracting, equipment development and supporting services, technological development and service, and other businesses for power supply & distribution and automatic control of kiln, proportioning, feeding, air supply, water supply, electrolysis and supporting facilities and other projects in metallurgical fields such as copper, lead, zinc, nickel, precious metal, rare metal, light metal, laterite processing, and polysilicon manufacturing.
(1) Oxygen bottom-blowing smelting automatic control technology
Oxygen bottom-blowing smelting technology is a smelting technology developed by ENFI with independent intellectual property, and is featured by good environmental protection, good adaptability to raw materials, high recovery rate of valuable elements, low energy consumption and small investment etc. Taking oxygen bottom-blowing copper smelting for example, when oxygen bottom-blowing smelting, converter converting and rotary anode furnace refining are used for blister copper smelting process, the copper recovery rate in smelting can be 99.0%.
Oxygen bottom-blowing smelting automatic control system, with oxygen bottom-blowing smelting process as the basis, allows optimal control for core equipment of main processes such as bottom-blowing furnace, reduction furnace and fuming furnace, as well as waste heat boiler, vibrating system and other equipment using advanced detection device and control technology.
(2) Oxygen-enriched top-blowing smelting plant-wide automatic control technology
Oxygen-enriched top-blowing smelting technology is a technology improved according to the rich engineering experience of ENF on the basis of Ausmelt top-blowing smelting technology. This system is featured by stable furnace conditions, stable furnace temperature, accurate position of lances, little grid disturbance, convenient operation, safety and reliability etc., and is proven to have reached advanced level of similar top-blowing furnace system control by practices.
This technology has been granted with multiple national patents.
(3) Composite furnace (flash furnace) smelting automatic control technology
Composite furnace smelting technology is a copper smelting technology jointly developed by ENFI and Jinchuan Group with independent intellectual property. If flash smelting, converter converting and rotary anode furnace refining process of this technology is adopted, copper recovery rate can be 98.6%, and this technology is featured by energy conservation, dust reduction and small investment, etc. Composite furnace smelting automatic control allows process parameter measurement and full-automatic control for main process flows such as composite furnace copper smelting, PS converter converting as well as supporting proportioning & feeding system, waste heat boiler, etc. This system keeps DCS as the core, with complete system architecture and communication network, and reduces the work load of employees using flash furnace single concentrate nozzle automatic control technology and real-time elastic furnace expansion displacement observation technology etc. This system guarantees not only the stability of metal grade, but also system stability, safety and low operation cost.
(4) Large roaster control technology
ENFI designed the first large fluidized bed roaster for zinc smelting in China by introduction and conversion. With mature roaster technology as the basis, 109m2 roaster designed by ENFI was completed and put into production in Baiyin, Zhuzhou, Qujing, Yuguang and other places in succession. In order to further improve the production efficiency, 150m2 fluidized bed roaster is developed on the basis of 109m2 fluidized bed roaster, and is featured by large capacity, good thermal stability, easy furnace control, good integrity and tightness etc. 90% of newly-built, modified and expanded large zinc smelters in China adopt this fluidized bed roasting technology designed by ENFI.
The control circuit of main plant building of roaster includes: roaster feeding control, roaster temperature control, roaster blast flow control, roaster blast pressure control and roaster outlet pressure control.
(5) Electric furnace automatic control technology
For the electric furnace control method independently developed by ENFI on the basis of the expert system, its core configuration software package is ENFI-(Electric Furnace) Advanced Power Control System (EF-APC system for short). EF-APC system has been applied in the control system of electric furnace for slag cleaning of copper smelting, electric arc furnace of vanadium-titanium magnetite and high-power electric furnace of ferronickel. The operating effect proves that this technology can significantly reduce control error compared with manual control and reduce the impact of electric furnace load on the power grid, and that the highest energy-saving effect can be more than 10%.
(6) Pressure leaching automatic control technology
Pressure leaching technology has the advantages of good selective leaching effect, high recovery rate of valuable metal and rapid reaction etc. Taking copper anode slime pressure leaching - oxygen top-blowing smelting technology for example, copper and tellurium leaching rates exceed 90%, and gold and silver recovery rates exceed 98.5%. ENFI designed different control system solutions according to different features of pressure sulfuric acid leaching, oxygen pressure leaching, high pressure acid leaching of laterite, etc. This technology has been used in multiple pressure leaching projects in the world and is praised by owners.
(7) Large fan drive and control integration technology
Based on engineering projects, ENFI independently develops fixed limit flow anti-surge control protection method and corresponding large fan drive and control system according to different fan drive systems and control requirements of the controlled object. This system has been used in multiple projects in the world. All projects that have been put into production are stable in operation and reliable in protection and no anti-surge protection malfunction or protection failure occurrs.
At present, ENFI is developing next generation variable limit flow anti-surge control algorithm.
(8) Polysilicon production automatic control technology
Polysilicon production technology is a high technology and core technology of ENFI with independent intellectual property. Polysilicon production automatic control system is independently developed from system integration, software configuration, debugging, and commissioning, using DCS system and intelligent control software package, and control policies such as PID control, complex control and expert intelligent control. Complex time sequence adjustment and safety protection interlocking control device, together with purifying column nonlinear control scheme of expert intelligent control policy guarantee polysilicon production stability, reliability, and safe operation.
(1) Ramu nickel-cobalt project in Papua New Guinea
The project, located in Madang Province, Papua New Guinea, is the largest overseas nonferrous mining investment project of China so far. This project integrates mining, beneficiation and smelting, and is among the challenging top industry projects around the world in terms of technological difficulty and scope of works. It is put into production in 2012.
The control system network covers the mine area, slurry pipeline transportation area and smelting area, and is about 150km long in total. Redundant industrial Ethernet is used for the whole network, and clock synchronization control is achieved. The control system has a scale of 16,000 points, and allows network communication with the control devices of dozens of equipment integrators. The control room breaks the traditional nonferrous enterprise control mode, is no longer divided by building but product area. It adopts a new control mode realizing local distributed control of control system cabinet and concentrated control of control system operator station, reducing the number of operators and giving full play to the superiority of the control system.
(2) Chambishi copper smelter project in Zambia
It is the largest smelter built in Africa by China at present. The designed production capacity is 150,000 t/a blister copper and it is put into production in 2009.
America ROCKWELL Controllogix 5000 control system is used and integrated control from production process automation to production information & dispatching management is realized. ENFI completed the whole process of ISA smelting control technology from independent design, control system configuration and debugging to final production and operation.
This project has 15 patents relating to automatic control that are granted by China.
(3) Chihong Huize lead-zinc smelting and comprehensive smelting slag utilization project in Yunnan
For Huize 60,000t/a lead bullion, 100,000t/a electrolytic zinc and slag comprehensive utilization project, complex and low-grade lead and zinc resources are used as raw materials for comprehensive treatment. Total output of lead and zinc is 200,000 t/a.
FCS field bus control system is used for plant-wide production process control. The number of control points in the whole plant exceeds 25,000 and the number of control circuits exceed 200. There are 1,138 FF field bus instruments and 75 wireless instruments. This project is the first in nonferrous industry as regards system sizing, number of FF field bus instruments and wireless instruments at present. Its technological and equipment level has reached international advanced level in the nonferrous industry.
(4) Plant-wide control and production management system in Daye non-ferrous smelter
Daye Nonferrous Metals Group Holdings Co. Ltd’s 300,000t/a copper smelter uses oxygen-enriched top-blowing AUSMELT smelting furnace - electric settling furnace - PS converter converting - rotary anode furnace refining - casting process. High temperature offgas enters waste heat boiler for heat recovery and the steam produced is used for power generation; SO2 offgas enters sulfuric acid system after dust collection.
In order to improve the overall labor productivity of enterprise, advanced distributed computer process control system (DCS) is used for main workshops of the smelter – proportioning, AUSMELT smelting furnace workshop and waste heat boiler, acid-making workshop, power generation workshop and tank house.
AUSMELT top-blowing smelting
300,000t copper tank house
Plant-wide management and dispatching network diagram
(5) Houma smelter project of Zhongtiaoshan Non-ferrous Metals Group Co., Ltd.
For Zhongtiaoshan Non-ferrous Metals Group Co., Ltd.’s Houma smelter, America Honeywell TDC3000 control system is used, 3 system control stations are arranged and plant-wide networking is realized. The 3 system control stations are smelting and proportioning system, acid-making system and oxygen-making system.
This project is China's first time to introduce Australian Ausmelt smelting technology. Entrusted by Zhongtiaoshan Non-ferrous Metals Group Co., Ltd. and the Australian party, ENFI completed the DCS control system configuration and software development for Ausmelt furnace system, proportioning and auxiliary section system and acid-making system, etc.
Main control display of the feeding system
Cleaning process control display
Drying & absorption process control display
Conversion process control display
(6) Yunnan Tin Company Limited project
The DCS of Yunnan Tin Company smelter’s smelting system and waste heat power station is YOKOGAWA CENTUM CS 1000 system, which is a production control system for small and medium-sized process control. This system is featured by reliability, universality and personal computer environment openness etc., thus facilitating system configuration and operation control.
According to the whole-plant process control requirements, smelting DCS consists of two independent CENTUM CS1000 systems: Ausmelt system and YTCL system. Ausmelt system is mainly to monitor and control Ausmelt furnace part, while YTCL system is to monitor and control the auxiliary part of Ausmelt furnace and other process flows. Shielded cables are used to connect the I/O card of the two systems for realizing point-to-point data communication.
Smelting DCS structure diagram
Main control display of feeding system
Master control display of waste heat boiler
6,000KW power station’s DCS consists of 3 control stations, 1 engineer station and 1 operator station. The control system structure diagram is as follows:
Main control display of steam turbine unit
(7) Henan Yuguang Gold and Lead Group Co., Ltd. project
Henan Yuguang Gold and Lead Group Co., Ltd., built in 1957, is the largest lead smelting enterprise in the world and the largest silver production enterprise in China. ENFI developed oxygen bottom-blowing smelting and oxygen bottom-blowing continuous converting "SKS-BCC process" on the basis of the patented technology of oxygen bottom-blowing smelting, and it realized industrialization in the smelting slag handling technology improvement of the project, which is epoch-making.
For the main smelting plant building (bottom-flowing smelting furnace, bottom-flowing converting furnace and anode furnace) of the project, Emerson Delta-V series distributed control system is used for the monitoring and control of the process flow, and the software configuration programming is completed by ENFI. Proper detection device and control technology are used for the project according to the process, and standard control system is formed by preparing process control software package, thus improving oxygen bottom-blowing smelting and oxygen bottom-blowing converting process control level. It is popularized in similar projects as a process control package.
(8) Myanmar Tagaung Taung nickel project
It is the largest overseas investment project of China Nonferrous Metal Mining (Group) Co., Ltd. and also a typical project of Chinese enterprises for overseas laterite-nickel development.
Project power source is from Shweli hydropower station, and is connected by 2-circuit 143kM overhead line. The designed 220kV general step-down substation guarantees the power demand of the whole enterprise.
In the project, ENFI developed China’s largest laterite smelting electric furnace – 72MVA laterite ore-smelting electric furnace with the independently designed and popularized rotary kiln – electric furnace ferronickel production technology. This electric furnace and electromechanical integration technology has independent intellectual property, is featured by full-sealing, low energy consumption, copper block cooling, high voltage operation, full-automatic control etc., and reaches international advanced level. Hot material conveying system and electromechanical integration technology, featured by high thermal insulation, high environmental protection and full automation etc., can not only reduce about 20% smelting energy consumption, but also improve work efficiency, meeting the environmental protection requirements.
(9) Nickel carbonyl project in Jinchuan Nonferrous Metals Holding Co., Ltd.’s smelter
ABB Industrial IT AC800F system is used for Jinchuan Nonferrous Metals Holding Co., Ltd.’s smelter. This project uses copper-nickel alloy after granulation as raw material, and makes high-purity nickel powder with carbonylation metallurgy. The technological process is featured by high pressure, poisonous, flammable and combustible etc., and has high requirements for instrument measurement, control and automatic adjustment.
(10) Field bus control system in Zhuzhou Smelter Group’s atmospheric pressure oxygen-enriched direct leaching project
Atmospheric pressure oxygen-enriched direct leaching technology remains at advanced level in international lead and zinc smelting industry. ENFI introduced and assimilated the atmospheric pressure oxygen-enriched direct leaching technology of OUTOTEC for zinc sulfide concentrate, and independently developed comprehensive leaching for zinc sulfide concentrate and neutral leaching slag, rare metal recovery, fluorine and chlorine removal, and iron precipitation residue recycling and other techniques, which are integrated with existing traditional zinc smelting process, forming a series of new processes and new equipment with independent intellectual property.
(11) 500,000t/a multi-metal mine comprehensive collection and recovery technical modification project of North Copper Co., Ltd.’s Yuanqu smelter
Yuanqu smelter’s DCS is the core of 500,000 t/a multi-metal mine comprehensive collection and recovery technical modification project in North Copper Co., Ltd.’s smelter. Bottom-blowing furnace smelting - converter converting - anode furnace refining pyrometallurgical process is adopted. ENFI undertook the design, integrated supply, construction, configuration and debugging of the automatic control system for the project. In the project, ENFI's proprietary technologies such as bottom-blowing furnace smelting and anode furnace natural gas reduction were successful in automatic control. Meanwhile, ENFI overcame a lot of difficulties and fulfilled the configuration and debugging tasks, accumulating a lot of valuable experience in control system project construction. The project was put into production successfully in February 2014.
(12) Quzhou Huayou new cobalt material Co. Ltd.’s 10,000t/a (cobalt metal tonnage) new material project
The designed capacity is 10,000t/a (cobalt metal tonnage) cobalt products, which are cobaltosic oxide, ceramic-grade cobalt oxide, cobalt carbonate and high-purity cobalt. Meanwhile, there are byproducts such as copper cathode that meets Grade A cathode copper standard in GB/T467-2010, ammonium sulfate, ammonia chloride and manganese sulfate, crude nickel salt and sodium hypochlorite
ENFI undertook the whole-process service from design, supply and integration, construction & installation to commissioning for the plant-wide automatic control system and industrial television monitoring system of the project. During the commissioning, since the raw materials keep changing and the process flow is immature, improvement started when the project was not put into production yet. ENFI made quick responses and nearly completed corresponding configuration display and control logic modification when the owner finished process improvement, thus guaranteeing the smooth trial production of owner, and it was fully recognized by the owner.