Laterite nickel processing,preparation of the metal for use in various products.
Although it is best known for its use incoinage, nickel (Ni) has become much more important for its many industrial applications, which owe their importance to a unique combination of properties. Nickel has a relatively high melting point of 1,453 °C (2,647 °F) and a face-centred cubic crystal structure, which gives the metal good ductility.
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Laterite nickel processing smelting methods and processes are as follows:
The preprocessing step is the raw material of nickel laterite ground with carbon material and flux limestone mixed, and then continuously input laterite nickel ore by rotary kiln. In the rotary kiln, the flow of hot gas from the combustion of the material and the coal is subjected to all the melting steps, drying, dehydration, reduction and metal growth. The metal is formed in a semi molten condition in the kiln. Frit material firing from the rotary kiln out it will be water broken, grinding, by gravity and magnetic separator will be returned to the nickel iron alloy from the discharge of the frit isolated. A diameter of 2 to 3 mm of sand like particles isolated nickel iron, and entrainment 1-2% slag, the chemical composition C0.1%, Ni18~22%, S0.45%, P0.015%. No matter how high the sulfur content of this product is applicable to the steelmaking process, because there is a good desulfurization capacity of steel. Sand like particles in the process of steelmaking is conducive to continuous feeding and rapid dissolution as a coolant material.
Recovery of nickel laterite rotary kiln production process of nickel and iron ratio is very high, are more than 90%.
Laterite Nickel Processing
Nickel is a slightly yellow silver white metal, is a kind of magnetic transition metal. Nickel is used for corrosion resistance, and the corrosion resistance of the alloy is increased. Stainless steel and alloy production field is the most widely used field of nickel. About 2 / 3 of the world’s nickel is used for stainless steel production, so the impact of the stainless steel industry on nickel consumption in the first L. The main effect of nickel in stainless steel is that it changes the crystal structure of the steel. One of the main reasons for the increase of nickel in stainless steel is the formation of austenite crystal structure, which improves the properties of stainless steel such as plasticity, ductility, toughness and so on. At present, the world’s non-ferrous metals, nickel consumption is second only to copper, aluminum, lead, zinc, ranking fifth in non-ferrous metals. Therefore, nickel is regarded as an important strategic material, which has been valued by all countries.
The main component of nickel as nickel and iron, also containing Cr, Si, S, P, C and other impurities. According to international standard (ISO) nickel in nickel content points for FeNi20 (Ni 15% ~ 25%), with FeNi30 (Ni 25% ~ 35%), FeNi40 (Ni 35% ~ 45%) and feni50 (Ni 45% – 60%). And divided into high carbon (C 1.0% ~ 2.5%) and carbon (C 0.030% ~ 1.0%) and low carbon (C <0.03%); high phosphorus and low phosphorus (P <0.02%) (P <0.030%) nickel iron. Currently the domestic manufacturers to produce ferronickel grade mainly concentrated in 1.6 ~ 2.0%, 4 ~ 8% and 10% ~ 15%, at the same time, there are a small part of the manufacturers to production of nickel content in more than 20% nickel iron.
There are two kinds of nickel resources in the world, one kind is sulfide ore deposit, the other is the oxidized ore deposit. Because the resource of nickel sulfide ore quality, mature technology, is about 60%~70% of the nickel production from sulfide ore. And about 65% of the world nickel reserves stored in nickel oxide ore deposit in, due to its due to the presence of the sake of iron oxide were red, so also known as laterite. The laterite nickel ore in the discovery of multiple distribution along the south, north of the Tropic of cancer, such as Australia, Papua New Guinea, New Caledonia, Indonesia, the Philippines, Cuba and other places.
Laterite belongs to non crystalline minerals. Different types of nickel ore, the composition fluctuation range: Ni 0.87% ~ 3.85%, Fe 6% ~ 50%, MgO 1.5% to 32%, SiO2 5% ~ 58%, Al2O3 from 1% to 15%, P = 0.000 4% ~ 0.000 2%, 0.001% s ~ 0.08%.
Another characteristic of laterite nickel ore is high moisture, especially at present our country laterite nickel ore imports in the Philippines and Indonesia bilateral climate rainy and humid, nickel in water fluctuations in the range of 30-35%. In order to ensure the ferronickel smelting furnace, nickel ore must be dehydrated in front of the stove, making block processing. Different manufacturers of nickel iron nickel ore sintering furnace before dehydration treatment commonly used several pretreatment methods:
- Rotary kiln drying, building block, rotary kiln, high temperature dehydration, preheating.
- The rotary kiln drying, agglomeration, sintering, pre reduction shaft furnace.
- Rotary kiln drying, dehydration, sintering (including pre reduction).
Different ore processing technology of investment cost and process operation of different difficulty, the influence on the whole process of ferronickel smelting comprehensive energy consumption and product quality are different. Therefore, with the scale of ferronickel production in our country, choose what kind of nickel ore pretreatment, worthy of analysis.
The significance of ferronickel industry
With the development of our country’s economy and the improvement of people’s living standard, the production and consumption of stainless steel is increasing rapidly. Nickel chromium nickel stainless steel is the main stainless steel varieties, because of its excellent comprehensive performance, has been widely used, accounting for 60% ~ 75% of the total output of stainless steel. Stainless steel production growth will pull the nickel metal consumption growth. With the impact of the financial crisis subsided, nickel prices return to more than $2 million, nickel iron alloy to reduce the stainless steel smelting cost advantage has been reflected, NiFe in stainless steel raw materials occupy the important position, domestic nickel smelting industry experienced a recession in the 08 years of decline after the defeat in the re ushered in the another development opportunity.
Accounted for only occupying the volume of is opposite in the near future, and in addition, due to the electrolytic nickel is mainly from sulfide nickel ore smelting income sulfide ore extraction technology is mature, long time of a large number of mining in the world for the development of sulfide ore resources have not much, coupled with sulfide ore resource exploration cycle and construction cycle is long, development and utilization is relatively difficult, and sulfide nickel laterite nickel ore resources rich, stored in laterite nickel metal nickel reserves of 65%, and every year from nickel oxide ore extraction of nickel nickel production of 30%, so as the world nickel sulfide ore resources gradually reduced from nickel oxide ore extraction of nickel metal will have great prospects for development.