Jiangsu Pengfei Group is national large-scale enterprise, key enterprises of China Building Material Machinery, leading enterprises of China Cement Machinery, Jiangsu Keeping Contract & Credit Enterprise, Jiangsu AAA level credit enterprise, producing and exporting base of 2500tpd, 5000tpd new type dry process rotary kiln cement equipments of the Ministry of Foreign Trade and Economic. We have the integrative capacity to supply complete set of services from designing, complete set of equipment, erection & commissioning. 

Jiangsu Pengfei Group has powerful machinery processing capacity, max. turning round and hobbing process diameter is 12m, annealing furnace is 6.5m, indoor max. lifting capacity is 200t, max. open-air lifting capacity is 150t, have the rotary kiln cement machinery processing capacity with the diameter less than 6m.China Top Brand “Pengfei” cement rotary kiln sale amount is the second one in whole nation, enterprise gained the title“Chinese Cement Machinery Leading Enterprise, Top 20 of China Building Material Machinery. Our company is the integrative group on basis of building material machinery, electrical, environmental protection, chemical machinery, new type building material as future economic growth and has been approved by ISO9001 quality system.  Its key product rotary kiln calcination system, high efficient ball mill, EP filter, micro-computer self-control, pre-water granulating equipment, separator, etc. has been approved by ministerial level, and gained national patent, national project of the spark plan, Jiangsu Province high-tech product title, accepted the favor from local and foreign customers.

Our company has the self-developing centre and special scientific employees and each year our company invested over 4% of total sales amount on the researching and developing. Set up developing studio, actively encourage developing employees to self-innovate, constantly focused on the advanced level, continuously promote technical improvement and innovation, insist on implement self-innovation based on digestion and absorption and improve the core competition of enterprise depending on scientific progress. After years development, our company has formed the rotary kiln series product with proprietary intellectual property rights, gained 35 patents, product quality and performances has reached international advanced level. Others, strengthen the cooperation with Tianjing Institute of China Sinoma, Nanjing Institute, Hefei Cement Research & Institute, Southeast University, Yancheng Engineering Colleague, Russia STROIPROEKT (construct) survey and design institute etc., the self-innovating capacity of our company has been obviously strengthened according to digestion and absorption of new technology, 5000tpd, 2500tpd complete set of cement equipment has been developed, have had the manufacturing capacity of these equipments and become the national leading manufacturing enterprises of large dry process cement rotary kiln.

 

At present our smelting process is basically located on the fact based on single product of electrolytic nickel as main product. Developing the technology of  utilizing laterite nickel ore to producing nickel iron is necessary. Laterite nickel ore utilized to produce nickel iron is reasonable on economy, no need to produce electrolytic nikel. In recent years, in order to ensure to meet the demands of nickel for national economical development, a group of enterprises implemented the developing policy of “Going Out”, take part in developing the nickel ore resources which play a role in the stable supply to our country. Nickel oxide ore is widely distributed nearby equator, the distance is close and the freight charge is not high. Comply with the dry up of nickel sulfide ore, the development and application of nickel oxide ore (laterite nickel ore) is rapid in the world. 

1. General description of smelting process of nickel oxide ore

At present, original nickel producing by the raw material of the nickel oxide ore, could be dived pyrometallurgy and hydrometallurgy. The production of utilizing Pyrometallurgy to produce nickel metal still occupies important location. But in recent years hydrometallurgy process gained rapid development, newly set up some factories utilizing high pressure acid leaching process to produce nickel and cobalt. Hydrometallurgy could be divided into two kinds: one is ammoniacal leaching, due to the limitation on raw material and cost, no new factory is set up in recent years. The other kind is acid leaching which is suitable for nickel oxide ore with low magnesium, the cost is lower, but some technical problems are still hanging, however seeing from the resources application and energy-saving, high pressure acid leaching process has advantage and potential and it has become important researching subject. But from the investment, construction circle and maturity of technology, a group of new factories are estimated to set up for pyrometallurgy whose product could be nickel ore or Ni-S. 

2. General description of pyrometallurgy 

Pyrometallurgy process could be divided into two categories: blast furnace (BF furnace, means blast furnace) smelting and rotary kiln-- submerged arc furnace – revolving furnace (RKEF) smelting process. 

2.1 Process of blast furnace smelting nickel iron 

After finding out the laterite ore in 1863, BFI process is used to treating this kind of Magnesian silicate nickel oxide ore. Due to the reasons of power consumption, environmental protection, investment and production cost, etc. this kind of process has been eliminated. Except China, there is no factory utilizing this kind of process to produce nickel iron in the world ( the last factory stopping production is Russia Wulaer Nickel Company and Wufali Nickel Factory). Blast furnace smelting process is simple, process flow is: The raw material will be treated according to the condition of incoming factory ( For example pick up the block with lower nickel content by hand, then crush and screen), then add the reducer and flux into nickel oxide ore via blending and batching equipment of sintering machine and evenly blend ( granulator could be used, too). The blended material will be distributed in the rolley of sintering machine and then gain the sinter ore with nickel after sintering. Then sinter ore will be sent to material yard of blast furnace and added into blast furnace via screening. After smelting, nickel iron with high harmful substance and low nickel which could be widely used for stainless steel smelting to reduce nickel content of rough nickel iron. In order for this, some fine measuring for removing the phosphorus, silicon, carbon and sulfur, etc. harmful elements.  While this fine measures could improve the nickel content of nickel iron according to customers’ requirements. The reason for eliminating the smelting process of blast furnace: 

1st, there is no efficient solving method for the environmental pollution problem of this process, except for the traditional blasting furnace pollution, in order to improve the fluidity of slag and reduce heel of furnace body and add the fluorite (C a F) into material of furnace，and in order to avoid the fluoride pollution, this operation should be forbidden. For the nickel oxide ore with higher A1:O, as the fluoride percent added into furnace body is large, this problem is more serious. As the intensity of sinter ore produce by laterite nickel ore, it is not suitable for utilizing large-scale blast furnace to smelting, normally small smelting blast furnace and small sinter machine are used for nickel iron production. The blast furnace producing nickel iron in China is 5 0 m N3 8 0 m 3 ( According to the report, there is smaller blast furnace, mainly is the blast furnace with smaller size of 150m), sinter machine is from l 8 m Ns o m.  Some nickel iron producing factory is lack of necessary environmental protection measures, Carbon oxide, Sulfur oxide, fluoride and powder has caused serious environmental pollution of around environment. This kind of method utilizing eliminated ferrous metallurgy equipment to produce nonferrous metal. 

2nd, the recovery of nickel is low. This kind of process producing nickel iron, nickel recovery of ore is normally lower than 90%. Some factories still stay in the primary producing status of producing rough nickel iron, there is no fine smelting workshop of nickel iron. Thus, this recovery has difference with the nickel recovery found in the foreign article. 

3rd, the power consumption is high and hard coke with high price is on demand. From the sintering process, based on the characteristics of power consumption on small sinter machine, the power waste factory caused the high return ratio. From blast furnace process, one reason for eliminating small blast furnace is power waste, now large slag quantity is raised. The coal gas of blast furnace and waste heat of some factories don’t have efficient recycling, precious power is wasted meanwhile environment is polluted. 

4th, impurity content is high without smelting, it doesn’t meet the international nickel trade standard. We request the nickel iron to have high nickel content, with low carbon, silicon, sulfur and phosphorus content. Nickel iron produced by blast furnace of our country is almost the product with high carbon, low nickel and high silicon, the phosphorous content is decided by raw material, but now the raw material with low phosphorous is short supply. The nickel value of this kind of semi-finished product is lower than the nickel value of qualified nickel iron; while iron element is almost send to customers for free.

5th, the investment per unit nickel production is large: 1) the investment on construction of mechanical material yard, sinter machine and blast furnace is higher than that of RKEF process. Of course utilizing current and industrial policy to eliminate the small equipment producing nickel iron, the investment is saving. This kind of process has been developed under the disadvantaged implementation of low price laterite nickel ore, high price nickel, environmental protection policy and power policy. The price of laterite nickel ore is sure to be increasing, nickel prie will fall back to reasonable price level, national environmental protection and energy-saving policy will be executed, this kind of process will quit the competition of market.  2)Pyrometallurgy RKEF process was developed on 50s of last century, at present replace blast furnace process to produce nickel iron. This kind of process creates the new article of pyrometallurgy to produce nickel iron. According to incomplete statistics, there are 17 countries utilizing this kind of process to produce nickel iron. Basic process flow: Ore treating and preparation of reducer—rotary kiln calcination – heat loading into submerged arc furnace smelting – external desulfurization of rough nickel iron – remove the silicon, phosphorous, carbon, sulfur, manganese, etc. impurity in converter – water casting of fine nickel iron, others the workshop of recycling and utilizing iron and nickel of slag inside converter should be constructed. 

 

( 1 ) Ore treating and the preparation of reducer

After ore delivered into raw material yard, after crushing and even blending, add reducer and then send into rotary kiln. While some factories make the pre-drying treatment on material before loading into rotary kiln or add the granulating process. The matching ratio of material is important which pay the decisive role to avoid ring formation of rotary kiln ( material sticked to the inner liner of furnace), control conductivity of furnace material and separate the slag and metal (nickel, iron) of submerged arc furnace. 

( 2 ) Rotary kiln calcination

The working area of rotary kiln could be divided into three section, means drying section, heating section, roasting section. In rotary kiln, ore is roasted for dehydration, weight decrease about 30%. Meanwhile, nickel oxide and part iron could be restore by reducer of furnace material. Set up sealing discharge device of rotary kiln discharging end, nickel slag will be send to material supply bin of submerged arc furnace under the temperature of 6 00～9 0 0℃ in insulation status, then evenly distribute inside of submerged arc furnace via a sealing tube distributing device. According to different treating method of furnace material, rotary kiln has different ratio between different diameter and length. The burner structure of rotary kiln is important, efficiently adjust the length and rigidity of entire fire to ensure the working temperature of three working areas inside furnace locates in the required range of process. Others, sufficiently consider the gas drying furnace material of rotary kiln to save energy. 

( 3 ) Heat loading into submerged arc furnace for smelting

After weighing the material discharged from rotary kiln, then these materials will be loaded into submerged arc furnace in heat status. While the loading system of submerged arc furnace need to be suitable for the demand of heat loading. Heat loading is important as except for the physical heat recovery, 2nd oxidation should be avoided during the transportation. In order for environmental protection, powder recovery, industrial health, coal gas recovery, the submerged arc furnace should be sealed. In submerged arc furnace separate rough nickel iron and slag of electric furnace via arc smelting, meanwhile reducing gas with 75% CO could be produced, after the purifying of gas which could be used as fuel of rotary kiln and occupies 30% of fuel of rotary kiln. According to different raw material, 1t raw material ore could gain 650-700kg nickel slag after roasting of rotary kiln while after smelting in submerged arc furnace, could gain 110-150kg rough nickel iron. While the nickel content of rough nickel iron normally is 10% -18%. 

 ( 4 )Fine smelting of rough nickel iron 

?During the process of tapping of ladle inside of submerged arc furnace, add barilla into ladle, the ratio of water is about 5-15kg each ton nickel iron, the sulfur of nickel iron water could decrease No.0 l 5% - 0.0 8 %.  Or spray granulated magnesium into ladle after tapping which need special evaporator to spray granulated magnesium into about 1.0m depth of ladle and this process could decrease the sulfur of melted iron under No. 0 l 5%. 

?Eliminate the slag on surface of rough melted nickel iron, add the acid into converter, then it will be oxidized via oxygen silicon. In order to control that the temperature of weld pool is not too high, add metal waste or waste material with nickel into furnace. 

?After desilication of nickel iron will be added into alkaline converter, remove the carbon, phosphorous and part iron here. During the smelting process, add limestone into converter. If there is enough waste material with nickel, lime could be used to replace limestone. The melted nickel iron discharged from alkaline converter could meet the requirements of nickel-iron standards of goods which could be used for sale of nickel-iron. Others, the 2nd step fine smelting of rough nickel iron is to replace the acid converter with alkaline converter which will utilize new process to implement desiliconization and desulfurization inside first converter. The melted nickel iron discharged from first converter will enter into 2nd alkaline converter for dephophorization and decarbonization. Add lime and limestone into converter during smelting process to ensure proper smelting temperature. 2nd fine smelting could gain fine melted nickel iron. 2.3 rough nickel iron directly smelt stainless steel process (during development) during the above mentioned two steps of fine smelting process, 2nd converter will change to utilize fine converter argon and oxygen which could directly produce 300series stainless steel. This kind of process could be used for constructing electric furnace for melting waste steel and adequately utilize the heat power of silicon oxidation to save energy and power, adequately utilize the iron element of rough nickel iron. This technology has tempting foreground, but it is still under quest.

Construct nickel iron producing factory need to consider the strategic target of long-term planning on integrated utilization of key resources and non-ferrous metals industry, it is necessary to choose suitable area to construct large nickel iron production base of China. But refrain from rushing headlong into action. Construct nickel iron production base should have following terms: ?implement the ore source: different ore is suitable for different smelting process. Pyrometallurgy process prior to choose the raw material of garnierite, before deciding to construct nickel iron factory, dry process pyrometallurgy nickel oxide ore source should be implemented. At present the price raising is a fact, the source of nickel ore will cause difficulty.