In order to meet domestic and foreign market demand and make full use of the resources, XX Silicon Industry Co., Ltd. determines to invest RMB 187,058,000 in establishing 14*8000kVA industrial silicon submerged arc furnace so as to form total scale of annual output of 50,000 tons of industrial silicon.
Industrial silicon is also called silicon metal or metallic silicon and is applied to metallurgy, chemistry, aviation, ship manufacture and energy development as important industrial raw materials. It is vital raw material for production of aluminium alloy, silicon bronze, other medium alloys as well as single crystal silicon. Meanwhile, it is a must for production of organic silicon and rubber etc. Besides, it can be further epurated into raw materials for smelting multicrystal silicon and manufacturing solar cell. It is applied more widely in development of new energy.
With rapid economic development of China and recovery of the world’s economy, both domestic and foreign market demand more and more industrial silicon. At present, the annual output is over 2 million tons. Industrial silicon project belongs to high energy consumption product, which is affected and restricted by supply of power and labor price. The production places for industrial silicon shifts from southeast coastal and northeast areas to the west regions. Ganzi Prefecture is advanced in supply of water, electricity and raw materials as well as labor resources. The Committee and Government of Ganzi Autonomous Prefecture pay great attention to silicon industry and determine to establish industrial silicon base with output capability of 50,000 to 80,000 tons. The project is greatly supported by the local government and people. Thus, the construction of this project will take full play of the advantages of the region as well as contribute to economic development in minority nationality regions. The project is meaningful and necessary.
The project is located in the original wood plant and air-entrapping brick plant in XXXX, Kangding County, Ganzi Autonomous Prefecture. The land belongs to classification III industrial land, covering an area of 160 mu. The location is agreed by Government of Ganzi Autonomous Prefecture in period II of Summary of Minutes issued on Feb. 21, 2006 and  No. 11 “Letter on Opinions on Location of Construction Project of 50,000 Tons of Industrial Silicon in Yuanyangba, Guza Town, Kangding County” issued by Construction and Environmental Protection Bureau of Kangding County. Construction Planning Bureau issues JG  ZI No. 21 Letter on Opinions on Location of Construction Project. People’s Government of Guza Town, Kangding County adjusts land use nature of XX Silicon Industry Co., Ltd. by issuing KGF  No. 25 Determination on Adjustment of Nature of Use of Some Land in Yuanyangba, Guza Town. The location conforms to the general planning of small towns of Guza Town, Kangding County.
According to Environmental Protection Law of the People’s Republic of China, Law of the Peoples Republic of China on Evaluation of Environmental Effects, and Regulations on the Administration of Construction Project Environmental Protection (Order No. 253 from the State Council), environmental effect evaluation shall be done. According to CHJ No. （2005378）review opinions on construction project environmental protection application form from Sichuan Environmental Protection Bureau, environmental effect report shall be prepared. Thus, XX Silicon Industry Co., Ltd entrusted Sichuan Metallurgical Industry Research Institute of Environment Protection and Monitoring to evaluate the environmental effect. The evaluation unit shall develop site survey and material collection and prepare environmental effect report according to the process and environment surrounding the plant and report to Sichuan Environmental Protection Bureau for reply as the gist for next design and acceptance.
1.2 Analysis on Conformity of The Industrial Policies
The project is chemical industrial silicon production project. The project adopts 14 sets of 8000KVA semiclosed short petticoat pipe submerged arc furnaces, with silica (containing over 99% SiO2) as the raw material and refinery coke and corn core as reductant (non- charcoal method). Three-phase pole is used to convert electricity into heat in submerged arc furnace so as to increase the temperature. SiO2 will be reduced into industrial silicon （Si）by C at high temperature. The project is approved by CTZB（5133210606211）No. 1915 Enterprise Investment Project Notice from Development and Reform Bureau of Kangding County. The project construction conforms to regulations of Order (No. 40) Guiding Catalogue of Industrial Structure Regulation (2005 edition) from National Development and Reform Commission. The project construction conforms to the national industrial policies and key development direction and task of Ganzi Prefecture.
1.3 Purpose and Principles of Evaluation
As a system for construction project management, environmental effect evaluation aims to carry through the basic national policy of “environmental protection” as well as the policy of “prevention first, combination of prevention and treatment and comprehensive utilization” so as to realize coordinate development of nature, economy and environment. Through evaluation, the local environment situation, effect degree and scope are known so as to make policy to prevent pollution as well as provide gist for proper arrangement, best design and management of environmental protection departments.
The environmental effect of this project lies in ambient air, sound environment and surface water. Thus, requirements for this evaluation are as follows: stating the feasibility of scale, location, layout and pollution prevention measures and proposing proper suggestion for possible problems as well as providing gist for environmental management and protection design.
(1) According to site survey and analysis, the ambient air, sound environment and surface water are known. Evaluate in terms of construction content and environment features so as to control the effect within regulated scope.
(2) Analyze the pollution in terms of emission and clean production, make clear the pollution source and strength, take prevention measures and calculate the emission quantity so as to provide gist for preparation of total quantity control plan.
(3) According to environment status and impact prediction, further prevention measures shall be proposed.
(4) According to the national requirements for saving water, improving recycling rate and protecting water resource, corresponding measures shall be proposed for guiding construction of the project.
(5) Evaluate the impact degree and scope of the project on the surrounding environment after its completion. Evaluate the feasibility of the environmental protection measures and propose proper suggestion by discussing the prevention measures to be adopted.
(6) Discuss the social, economic and environmental benefit of the project by analysis of the environmental economy.
(7) According to the analysis above and regional planning, national industrial and environmental protection policies, state the feasibility of the project in scale, location, layout and pollution prevention measures and proposing proper suggestion for possible problems as well as providing gist for environmental management and project construction.
1.4 Gist for Preparation
1.4.1 Laws and rules
（1）Environmental Protection Law of the People’s Republic of China （1989.12.26）
（2）Law of the Peoples Republic of China on Evaluation of Environmental Effects （2002.10.28）
（3）Law of the Peoples Republic of China on the Prevention and Control of Atmospheric Pollution （2000.4.29）
（4）Law of the People’s Republic of China on Prevention and Control of Water Pollution （1996.5.15）
（5）Law of the People’s Republic of China on the Prevention and Control of Environmental Pollution by Solid Waste （2005.4.1）
（6）Law of the People’s Republic of China on Prevention and Control of Pollution From Environmental Noise （1996）
（7）Law of the Peoples Republic of China on Water and Soil Conservation （1991.6.29）
（8）Law of the Peoples Republic of China on Promotion of Cleaner Production （2002.6.29）
（9）Order (No. 40) Guiding Catalogue of Industrial Structure Regulation (2005 edition) from National Development and Reform Commission.
（10）Regulations on the Administration of Construction Project Environmental Protection from Order No. 253 of State Council of Peoples Republic of China
（11）GF No. 39 Decision of the State Council on Implementing Scientific Viewpoint of Development and Strengthening Environmental Protection
（12）CFF No.（1996）142 Decision of People’s Government of Sichuan Province on Strengthening Environmental Protection
（13）GMJZY No.［2000］1015 Suggestions on Strengthening the Work of Water-Saving
（14）Notice on Strengthening Environmental Impact Management and Preventing Environment Risk as Per Law (CHF No.  1)
1.4.2 Relevant technical specification and document
（1）The project is approved by CTZB（5133210606211）No. 1915 Enterprise Investment Project Notice from Development and Reform Bureau of Kangding County.
（2）CHJ No. （2005378） Review Opinions on Construction Project Environmental Protection Application Form from Sichuan Environmental Protection Bureau
（3）GHH No.  38 Letter on Confirmation of Implementation Standards for Environmental Impact Evaluation of the Project of Annual Output of 50,000 Tons of Chemical Industrial Silicon of Kangding XX Silicon Industry Co. issued by Environmental Protection Bureau of Ganzi Tibet Autonomous Prefecture
（4）JG  ZI No. 21 Letter on Opinions on Location of Construction Project from Construction Planning Bureau
（5）KGF  No. 25 Determination on Adjustment of Nature of Use of Some Land in Yuanyangba, Guza Town from People’s Government of Guza Town, Kangding County
（6）KFH No. 28 Letter of People’s Government of Kangding County on Promise for Movement of Kangding County Yuanyangba Primary School from People’s Government of Kangding County
（7）Technical Guidelines for Environment Impact Assessment （HJ/T2.1～2.3-93）
（8）Technical Guidelines for Environment Impact Assessment （HJ/T2.4-1995）
（9）Technical Guidelines for Environmental Risk Assessment on Projects （HJ/T 169-2004）
（10）Relevant technical materials such as feasibility research report provided by XX Silicon Industry Co., Ltd.
(11) Materials about local society, economy, environment, hydrology and weather etc.
1.5 External Relationship of The Project
The project of XX Silicon Industry Co., Ltd is located in XXXX, Kangding County, Ganzi Autonomous Prefecture, on the right of Dadu River. It is 1393 m high above sea level. It is about 2 km away from the cross of National Expressway 318 and Provincial Expressway 211, 20 km away from the Kangding County, 51 km away from Guza Town, 8 km away from Huangjinping Reservoir, 20 km away from Luding County, 6 km away from Pengba Town, 2 km away from Lengzhuguan Hydropower Station and 15 km away from Luding River Power Station.
The project is located in alpine and valley landform, the river is in “כ” shape, surrounded by mountains. The location is close to Dadu River in the south and southeast, close to and about 185 m away from National Expressway 318 in the northwest and 77 m away from Wasi Primary School (about 180 persons, 1405 m high above sea level ). There are villagers (about 500 persons) of Xiawasi Village living in the range of 500 m in the north of the plant boundary. The electrical boost station of Kangding Power Co., Ltd. (1799 m high above sea level) is located 200 m away from the national expressway in the north. The distance of 250 m away from the north of the plant area and Dadu River is Kangzhou Village (1720 m high above sea level), with about 300 residents. There is also Kangding Qifa Electric Pole Plant, air-entrapping brick plants and small iron alloy plants about 37.5m away from the north of the plant. There are over 10 houses of Xiawasi Village about 185 m away from the plant. The office area of Sichuan Huaneng Kangding Co., Ltd. is 335 m away from the plant. The west of the plant is farmland, with oil station about 220 m away from the northwest of the plant area. Kangding Nationality Teachers College (about 10600 persons and 1596 m high above sea level) is located about 4500 m away from the north of the plant area. Shangwasi Village (about 800 persons and 1649 m high above sea level) is 3500 m away from the southwest of the plant area. Lengzhuguan Village (about 200 persons and 1680 m high above sea level) and Lengzhuguan Hydropower station (on the branch of Dadu River and 1689 m high above sea level) are located about 2000 m away from the southwest of the plant area. Refer to Table 1-6 for main environmental protection target situation in project evaluation areas. Refer to Attached Figure 3 and 4 for external environment relationship details.
1.6 Evaluation Factors and Keys
1.6.1 Evaluation Factors
(1) Evaluation factors of status survey
Surface water: flow, water temperature, pH, SS, CODCr, BOD5, NH3-N
Ambient temperature: TSP, SO2 and NO2
Noise: plant boundary noise and ambient noise
(2) Environmental effect prediction and evaluation factors
Surface water: CODCr
Ambient air: TSP, SO2
Noise: plant boundary noise and ambient noise
1.6.2 Evaluation keys
On the basis of deep analysis, evaluation shall focus on effect of eliminated smoke (powder) on quality of ambient air, validity and reliability of air pollution prevention measures and effect of noise on environment. Meanwhile, analysis shall also be made into effect degree and scope of eliminated wastewater on surface water and effect of construction period on regional environment.
2.7 Major Pollution Procedure and Improvement Measure of Works
Discharge and improvement of waste gas pollutants
Raw materials such as petrol coke cobs shall enter the factory in qualified sizes. The engineering waste gas is mainly originated from the fume of submerged arc furnaces and silicon outlet. The recommended air pollutants and emission are detailed in Table 2-10.
(1) Fume at the fire hole of submerged arc furnaces and silicon outlet
① Fume at the fire hole of submerged arc furnaces
The 14 submerged arc furnaces are the primary source of waste gas in the Project, and the main pollutants are fume and SO2.
During the smelting process of industrial silicon, a large amount of fume and CO as well as small amount of metallic steam will be generated in the melting pool of submerged arc furnaces. Afterwards, the furnace gas discharge level will be blended with air coming in through the furnace door. CO, H2, CH4 and other combustible constituents in the gas will quickly generate high-temperature fume in the charge level high-temperature zone, and Si and SiO will be re-oxidized to produce white SiO2 particles. The generated fume is about 60-100 times of the furnace gas. Moreover, the fume also comprises a little SO2 and NOx. See Table 2-11 for fume contents:
Table 2-10 Major Contents of Furnace Gas and Fume of Industrial Silicon Submerged Arc Furnaces
Name of waste gas
Chemical content (volume %)
Dust concentration in gas g/Nm3
Gas of industrial silicon furnace
The fume is a grey-white sphericity, mainly containing SiO2, accounting for 90% of the total fume. The fume size ranges between 0.02-0.25μm, accounting for 80% approximately. The main contents of the fume collected by the dust collector are as follows:
Table 2-11 Major Contents of Fume of Industrial Silicon Submerged Arc Furnaces
② Silicon outlet and fume from silicon outlet
Some fume will be generated when the submerged arc furnace are producing silicon and refining. The fume is discharge at intervals, and silicon is produced every 2 hours. The production of silicon each time shall last 30-45 minutes, and refining with oxygen blowing lasts 15 minutes. Dust concentration of fume is about 1g/Nm3.
③ Treatment method of waste gas
In the Project, each of the 14 submerged arc furnaces of 8000KVA shall have one set of short petticoat pipe, wind cooling tube, cyclone and bag-type dust collector (14 sets in total) provided by Elkem ASA of Norway. The capture rate of fume at the fire hole is 99%, and purification efficiency of dust collector is higher than 98%. The fume at the silicon outlet shall have a separate skid of fume hood and fan capture device, then the bag-type dust collector of fire hole fume shall be included. The fume capture rate at the silicon outlet shall range from 85% to 90%. The purified fume shall be discharged by 40m stack (each dedusting equipment shall have one stack, and 14 stacks in total), and the emission density is below, which reaches Class 2 emission standard of GB9078-1996 Emission Standard of Air Pollutants for Industrial Kiln and Furnace.
(2) Fugitive emission of fume
For the submerged arc furnaces of industrial silicon, the fugitive released fume and dust is mainly from the fume drifting from the fire hole during ramming, kickoff and feeding of smelting process, the fume resulted from the silicon production at the outlet and refining by oxygen blowing, as well as the dust escaping from leakage when dust is directed to the dust collector.
Control measures for fugitive emission: semi-enclosed short petticoat pipe shall be applied to the Project. After dust collector made by Elkem ASA of Norway is installed, slightly negative pressure will be formed in the petticoat pipe, which can effectively control the fume escape during feeding and ramming. The fume at the silicon outlet shall have a separate skid of fume hood and fan capture device. The fume hood of the silicon outlet shall be set right above the outlet, whose projection area shall be larger than that of silicon water drum. The lower edge of the fume hood of the outlet shall have the minimum distance from the upper edge of the silicon water drum, in order to ensure the capture rate will not be smaller than 85%. Aluminium silicate heat-proof fiber board shall be provided for the fume hood to avoid deformation and damage in case of high temperature. In view that the valley wind is heavy in the local place, the surrounding areas of submerged arc furnace factory, coke bin, coal bin etc. shall be enclosed, so that wind will not blow the fume out of the hood and the capture rate will not be lowered. Dust transport shall be realized by enclosed screw conveyor. After compacted, micro silicon powder will have its loose thickness increased to 0.5-0.6t/m3 before being bagged and sold to avoid the second dust drift. Harden and afforestate the floor surface of factory areas. High evergreen arbor trees shall be planted in the surrounding areas to resist wind and cast shade.
Fugitive emission of fume will be lowered greatly of the aforesaid measures are taken.本工程无组织排放浓度可控制在5mg/Nm3以内，每台工业硅矿热炉排放速率平均为0.093 kg/h，14台共1.3kg/h，达到《工业炉窑大气污染物排放标准》GB9078-1996二级排放标准。
In the Project, the fugitive emission density can be controlled within 5mg/Nm3, and the emission rate of each submerged arc furnace is 0.093kg/h on average, or 1.3kg/h in total. It has met the Class 2 emission standard specified in GB9078-1996 Emission Standard of Air Pollutants for Industrial Kiln and Furnace.