DEVELOPMENT OF HEMATITE BENEFICIATION AND PELLET TECHNOLOGY OF INDIA AND CHINA

By ceoaisra, Section TECHNOLOGY NEWS Posted on Tue Feb 05, 2008 at 01:46:02 AM EST

DEVELOPMENT OF HEMATITE BENEFICIATION AND PELLET TECHNOLOGY OF INDIA AND CHINA

Through the technology solution comparison of the hematite beneficiation and pellet between India and China in this paper, the conclusion can be summarized as below: China has rich experience in the technology of hematite beneficiation and pelletisation which can be completely applied in India hematite beneficiation and peilet industry and provide a platform for the cooperation of India and China's iron ore beneficiation and pellet technology.Keywords: beneficiation; pellet; hematite.

CHINA'S IRON ORE RESOURCE CONDITION

With fast and stable development of China's economy, the steel industry has been developing promptly. The requirement parameters of all the local steel companies have been increasing rapidly. We can't depend on only high quality ore resources from abroad just because the local ore mine can't meet the requirement far. According to the statistics, China imported iron ore more than 10 million tonnes in the year of 1985, while in 2002 more than l00 million tonnes, in 2004 more than 200 million tons, in 2006 more than 275 million tons. In the local iron ore resource, the easily to be beneficiated magnetite has become less and less. For the purpose of making best use of the local iron ore resource, enhance the degree of self-sufficiency of the local steel companies, reduce the ore importing pressure and keep in good supply of the high quality iron ore, we must promote the high efficiency development and utilization of the poor iron ore resource based on the science and technology improvement. In China the iron mine has a lot of deposits with complex deposit condition, ore types are too many, sulfur, phosphor and silicon dioxide etc. malign materials contents are high, multi component inter growth iron mine occupies a high ratio. Further more the useful components the inlet grain size are small, so the beneficiation with big difficulty, low rate and poor product quality. Due to poor quality of China's iron ore resource, causes the development of the iron ore beneficiation of China and the overall level is very high. Especially at recent years, we researched and successfully utilised the new advanced high efficiency beneficiation equipment, flotation reagent and new beneficiation process, so caused the beneficiation process index to get the breakthrough development.

THE BENEFICIATION PRACTICE OF CHINA'S HEMATITE

The hematite iron includes magnetite-hematite mixture ore, which is the important iron resource of China. In the beginning of 1960s, the main hematite processing technology with poor production index was baking-magnetic separation and single flotation. In recent years the hematite beneficiation got breakthrough because of the new process, new equipment and reagent are adopted.

ANGANG DIAO JUNTAI BENEFICIATION PLANT

The hematite is the only iron ore in the crude ore of AnGang Diao Juntai beneficiation plant, gangue is quartz, the crystallization grain of the mine is big. The beneficiation plant design capacity is 9MT/ year, adopted two sections continuous grinding mine, weak-separation--strong separation-- reverse flotation process. On the basis of iron grade 28 per cent, the beneficiation index reaches: the concentrate iron grade 67 per cent above, the iron recovery more than 75 per cent, tailing iron grade about 10 per cent.

ANGANG QIDASHAN BENEFICIATION PLANT

The hematite is the only iron ore in the crude ore of AnGang QiDaShan beneficiation plant, gangue is quartz, the crystallization grain of the mine is small. The beneficiation plant design capability is 8MT/annum. The original design adopted baking -- magnetic separation -- flotation process technology; the concentrate only can get the grade about 63 per cent. After the improvement of the process technology, adopted the process technology of stage grinding, rough concentrate rewashing and weak magnetic separation -- strong magnetic separation-- reverse flotation, so that on the base of crude iron ore 29 per cent can get the index of concentrate grade more than 67.5 per cent, the recovery rate higher than 70 per cent and the tailing iron grade about 13 per cent.

ANGANG HUJIAMIAO BENEFICIATION PLANT

The hematite is the only iron ore in the crude ore of AnGang HuJiaMiao beneficiation plant, gangue is quartz, the crystallization grain of the mine is asymmetry. The beneficiation plant design capability is 8MT/annum, adopted the process technology of stage grinding, rough and fine separation, weak magnetic separation -- strong magnetic separation-- gravity separation -- reverse flotation, so that on the base of crude iron ore 28 per cent can get the index of concentrate grade more than 67 per cent, the recovery rate higher than 70 per cent and the tailing iron grade about 11 per cent.

WUYANG IRON MINE TIESHANMIAO BENEFICITION PLANT

The hematite is the only iron ore in the crude ore of WuYang iron mine TieShanMiao beneficiation plant, gangue is quartz, the crystallization grain of the mine is asymmetry. The beneficiation plant design capability is 3.5MT/annum, adopted the process technology of stage grinding, weak magnetic separation--strong magnetic separation--gravity separation and reverse flotation for the tailing of gravity separation, so that on the base of crude iron ore 29 per cent can get the beneficiation index of concentrate grade more than 65 per cent, the recovery rate higher than 70 per cent and the tailing iron grade about 12 per cent.
TANGSHAN SIJIAYING BENEFICIATION PLANT
The hematite is the only iron ore in the crude ore of Sijiaying beneficiation plant, gangue is quartz, the crystallization grain of the mine is asymmetry. The beneficiation plant design capability is 7MT/annum, adopted the process technology of stage grinding, respective separation for rough and fine ore, gravity separation--magnetic separation--reverse flotation, so that on the base of crude iron ore grade 29 per cent can get the beneficiation index of concentrate grade more than 66.55 per cent, the recovery rate higher than 75 per cent and the tailing iron grade about 10 per cent.

CHINA'S IRON ORE PELLET TECHNOLOGY

Though the starting of China's iron ore pellet technology is late, the development is fast .In the beginning of 1990s, there were only several shaft furnace pellet plant with several million tonnes output, while till 2007 develops into more than 20 production plants and the output exceeds 100 million tons, the production equipment changed from the low efficient shaft furnace into belt baking machine and traveling grate machine-rotary kiln, the single equipment capability reaches 5MT/annum. The pellet plant newly put into production almost adopt imported iron ore with the main content hematite which is more than 80 per cent of the raw material. Since the magnetite is the main part of the iron concentrate in local, almost all producers blended the local magnetite during the pellet production. At present the ongoing WISCO No.2 pellet production line, and Bao Steel ZhanJiang pellet plant both adopt the hematite as the only iron ore material, the designed capacity is 5MT/annum. Almost all pellet plants of China adopt traveling grate machine-rotary kiln except a few who adopt shaft furnace and belt type baking machine. The advantages are saving the building investment, stable product quality, strong adaptability for the fuel, natural gas, oil and coal all can be used.

PROFILE OF INDIAN IRON MINE

India is one of the countries with the most abundant mineral reserves in the world. The basic reserve of the iron ore is about 23.58 million tonnes, of which about 12.9 million tonnes of hematite and 10.68 million tonnes of magnetite ore, ranking sixth in the world and accounting for about 6.8-7 per cent of the world's total reserves. At present, the output of iron ore India ranks eighth accounting for about 8 per cent of the world's total reserves. As the demands of domestic and export boosted in recent years, the iron ore output of India increased substantially. The annual output was 86.22million tonnes in 2002, and reached 145.94 million tonnes in 2005, of which 48.15 million tonnes for domestic demand and 78.14 million tonnes for export. Currently India's total iron ore mining capacity is 154.43 million tonnes annually, of which state-owned enterprises account for 51 per cent and the rest is produced by private enterprises. The lump ore that contains over 65 per cent iron accounts for 21 per cent of India's total iron ore output, and the iron ore fines that contains over 65 per cent iron accounted for 16.2 percent. The Indian government divides the resource into three grades according to the iron level: over 65 per cent is high-grade ore, 62-65 per cent is mid-grade ore, and less than 62 percent is low-grade ore. Of the hematite resources, 10.4 per cent are high-grade ore that concentrate in Chattisgarh, Orissa, Karnataka and Jharkhand; and 34 per cent are mid-grade ore that concentrate in Orissa, Karnataka, Jharkhand and Madhya Pradesh. Since many Indian iron ore resources are located in the nature reserves or in the jungles and mountains, it's difficult to exploit, so in the 23.58 billion tons of iron ore reserves of India the basic reserves that can be exploited is only 17.27 billion tonnes. Environmental problem has become a key issue affecting the future of India's iron ore resources exploitation. Such as the mine owned by Kudremukh Iron Ore Company (KIOCL) in the forest land of West Coast in Karnataka, has ever been India's largest single mine. The output of the raw ore reached 20 million tonnes annually, and its pellet ore also reached 350,000 tonnes every year, but because of the opposition of the domestic environmental organisations, the Indian High Court adjudged to close the mine at the end of December 2005.

INDIAN IRON ORE BENEFICIATION AND PELLET

Since the Indian iron resource almost is the rich ore with high iron grade, the grade more than 60 per cent iron ore occupies more than a half of the total. The already exploited mines have few beneficiation process and only a few mine add the washing process in ore crushing screening procedure, and leave the slime as tailings impoundment. The main raw material of the pellet is the powder of the rich ore, which utilizes concentrate from beneficiated ore. Under the present scenario with the stable growing of iron ore price, the question how Lo increase the utilisation rate of the iron resource and protect the environment of the mine has been the priority by the government and enterprises. On one hand, the slime obtained from the washing are comprehensively to be used, reduce the tailing impoundment and reduce the pollution for the air; On the other hand, beneficiate the powder which obtained from the lump ore production to reduce the silicon and alumina etc, gangue volume and improve the quality. Compared to China's hematite, Indian hematite has absolute priority in the grade quality. The grade of China's hematite crude ore is only about 30 per cent, while that of Indian ore can reach 45 per cent and above. Mono mineral crystallization grain of China's hematite is relatively coarse and the gangues are mainly quartz, the ore with high hardness is difficult to be slimed, so the separation rate is high. In the low-grade hematite of India, the grain of iron ore and gangue are both small and the gangue contents a large amount of alumino-silicate except, so the beneficiation should decrease silicon as well as aluminum. The sulphur and phosphor quantity contained in Indian hematite are also relatively high, so it's difficult for beneficiation. The hardness of the India's low grade hematite is low, which gives advantage of low energy consumption when crushing and grinding, while the disadvantage is the ore easily to be slimed and after sliming the ore can be washed away with water which cause low recovery of iron. Borrowing experience from the beneficiation of China, take beneficiation into the low-grade hematite of India and further utilize the concentrate beneficiated for pellet production has already got big improvement. Utilizing the high microseism gradient magnetic separator and combine the reverse notation process, can get concentrate grade about 66 per cent, SiO2, less than 4 per cent, A12O3 less than 3 per cent, the recovery more than 65 per cent as well the sulphur and phosphor content volume can be reduced. Recently the hematite pellet test of India got success and the pellet quality reaches the requirement of blast furnace iron making. Technically it's not a problem to use the concentrate from the low-grade hematite beneficiation for the pellet production.

CONCLUSION

From the comparison of hematite resource condition, ore property, beneficiation type index and the pellet technology between China and India, though the big difference exists in the quantity, quality and beneficiation type index, the rich experience of China in hematite beneficiation and pellet technology can be completely utilized in hematite beneficiation and pellet technology of India. The successful test and research in partial mine validate this point and will provide the reference for the cooperation of China and India in the beneficiation and pellet technology area.
Source by: Joint Plant Committee