Nickel Metal

Chapter 1: What is the principle of nickel metal?

This section explores the nature of nickel metal, its manufacturing process, and its various applications.

What is Nickel Metal?

Metals are materials known for their malleability, ductility, and excellent thermal and electrical conductivity. These can be divided into five categories, with nickel classified under transition metals. Nickel is a naturally occurring, lustrous, silvery-white metal with a slight golden hue. It has an atomic weight of 58.71, an atomic number of 28, and is represented by the symbol Ni. Nickel possesses five stable isotopes, remains solid at room temperature, and has a boiling point of 2730°C and a melting point of 1455°C. It is ferromagnetic, hard, resistant to corrosion and rust, and ductile. Being a naturally occurring element, nickel must be extracted through mining.

Nickel is acquired through a method known as extractive metallurgy. This process involves separating the desired metal from its ore and purifying it to achieve a higher level of purity. An ore is a naturally occurring rock found deep beneath the earth's surface, containing valuable minerals that can be mined, refined, and sold for profit. Typically, ores contain metals. Nickel's primary ores are categorized into two main types: laterites and magmatic sulfides.

Production Process for Nickel

Nickel primarily comes from two types of ore deposits: laterites, which consist largely of nickel-rich limonite and garnierite, and magmatic sulfide deposits, where the main ore mineral is pentlandite.

Extraction and Processing of Nickel

Extractive metallurgy is employed to obtain metal from its ore. Pyrometallurgical extraction is the most prevalent method, involving the use of high temperatures to facilitate chemical reactions. Laterite ores are typically extracted using open-pit mining techniques, where the ore is removed from a large, open excavation. In contrast, sulfide ores, often found in combination with copper, are mined underground. The equipment commonly used for mining laterite ores includes large shovels, draglines, and front-end loaders.

Nickel Extraction From Sulfide Ores

Once sulfide ores are mined, they undergo crushing and grinding to separate nickel from the waste materials through a method known as selective flotation. In this process, the ore is combined with reagents and then agitated with mechanical and pneumatic equipment that generates air bubbles. Sulfide particles, being lightweight, attach to the air bubbles and rise to the surface of the mixture.

The collected materials typically contain between six to twelve percent nickel. Magnetic separators are employed due to the magnetic properties of some nickel-containing sulfides, either as an alternative to flotation or in conjunction with it. Waste materials often undergo a secondary cleaning process before disposal. In cases where sulfide ores have nearly equal quantities of copper and nickel, a second selective flotation step is required to produce both a low-nickel copper concentrate and a separate nickel concentrate.

Nickel concentrates are often subjected to leaching with sulfuric acid or ammonia. Alternatively, they may be dried and then processed through flash smelting techniques. Today, flash and electric smelting are the predominant methods used. These processes involve introducing the ore into a furnace with preheated oxygen, which oxidizes the iron and sulfide, resulting in a nickel content of 25 to 45 percent.

The resulting nickel-iron sulfide is referred to as matte. In the final stage of processing, oxygen is introduced into the molten mixture to remove any residual iron and sulfide. The iron reacts with the oxygen to form an oxide, which then combines with silica flux to create a slag that is removed. This process yields a nickel matte containing approximately 70 to 75 percent nickel.

The entire process is carried out in a rotating converter. Part of the heat needed for smelting sulfide ores is generated by the reaction between oxygen and the iron and sulfur present in the ore.

Nickel Extraction From Laterite Ores

Nickel extracted from laterite ores is free of sulfur but contains significant amounts of moisture, both as water and hydroxides. Unlike sulfide ores, lateritic ores cannot achieve the same reaction temperatures, so additional energy sources are required for drying and smelting. The drying process, which removes moisture from the ore, is performed in a large kiln furnace.

The nickel oxide produced from the previous process is then reduced to obtain nickel metal. This reduction is typically performed in electric furnaces with a capacity of 45 to 50 megavolt-amperes. These furnaces operate at temperatures ranging from 1360°C to 1610°C.

Refinement of Nickel

After extracting and processing nickel ore, the resulting substance, known as nickel matte, typically contains around 75 percent nickel. Additional refining can enhance this purity to up to 95%. One method used for refining nickel, particularly from sulfide ores, is ammonia pressure leaching. In this process, nickel is recovered from the solution through hydrogen reduction, while the sulfur in the ore reacts to form ammonium sulfate, which can be utilized as a fertilizer.

Additional refining methods involve roasting the matte to produce high-grade nickel oxides, which are then treated with a pressure leach. The resulting solution undergoes further refinement through electrorefining and carbonyl refining. In electrorefining, an electrolytic cell is employed, using diaphragm compartments to prevent impurities from migrating from the anode to the cathode, yielding high-purity nickel. Carbonyl refining involves passing the matte through carbon monoxide, which produces nickel and iron carbonyls.

Shaping Process of Nickel

Once nickel has been refined, it can be machined into various forms, including bars, rods, plates, sheets, and tubing. Several techniques are employed to create these shapes, which are described in detail below:

Nickel Extrusion

This is the least frequently used method for forming nickel. It involves melting the nickel at extremely high temperatures and then shaping it by pushing the molten nickel through a die. This process produces nickel sheets, bars, rods, and tubing.

Cold Drawing

This method is more commonly used for shaping nickel compared to extrusion. It involves drawing the nickel tube or wire through progressively smaller dies without applying heat, which reduces its diameter. This technique is typically employed in the manufacturing of nickel tubes and wires.

Electroless Nickel Plating

This method involves using an aqueous solution with a chemical reducing agent to catalytically reduce nickel ions. The ions are deposited without the need for electrical energy, resulting in deposits with a consistent size and shape. This is the most widely used technique for shaping nickel.

What to Consider When Purchasing Nickel

When purchasing nickel, both customers and manufacturers need to consider several key factors to ensure the material meets their needs. Important aspects to evaluate include the expected exposure to environmental conditions like rain and heat, the stress and strain the nickel will be subjected to, its intended application, and the required dimensions. Additionally, choosing the right supplier is crucial. It's important for both customers and manufacturers to engage in detailed discussions with multiple suppliers to find the best prices, lead times, secondary services, delivery policies, and overall customer service.

Chapter 2: What are the different types and forms of nickel metal?

Nickel's valuable properties make it a popular choice for creating alloys with other elements such as chromium, cobalt, copper, and iron. One of the most common nickel alloys is stainless steel, which primarily consists of iron, 18 percent chromium, and 8 percent nickel.

Nickel alloys are categorized into the following types:

• Nickel-titanium alloys
• Nickel-chromium-cobalt alloys
• Nickel-chromium-molybdenum alloys
• Nickel-chromium-iron alloys
• Nickel-chromium alloys
• Nickel-molybdenum alloys
• Nickel-copper alloys
• Nickel-iron alloys
• Wrought nickel

Some alloys and forms of nickel are listed below. It‘s important to note that each of the types and forms of nickel listed below fall into a category of nickel alloys listed above.

Brushed Nickel

This type of nickel is finished with a wire brush or similar abrasive surface, creating a textured pattern while maintaining its shine. Brushed nickel is resistant to corrosion but can tarnish easily. Over time and with exposure, it may develop a milky white tarnish.

This issue can be easily addressed by cleaning the brushed nickel with a mild cleaner or a solution of water and white vinegar.

Brushed nickel is commonly used for producing:

• Door knobs
• House numbers
• Kitchen faucets
• Bathroom fittings
• Cabinet hardware
• Lighting fixtures

Casting Alloys

These nickel alloys are created by melting the alloy and pouring it into molds, making them easier to shape than other alloys. They offer excellent resistance to heat, corrosion, and wear, and are renowned for their high strength.

Cupro Nickel

This nickel alloy includes nickel, copper, iron, and manganese, with copper comprising 60 to 90 percent of the composition, making it the primary component. The alloy has a silver-like appearance.

Cupronickel is highly resistant to seawater corrosion, offers good thermal conductivity, is extremely ductile, and has strong tensile strength. Its applications include:

• Piping and heat exchangers
• Condensers for marine hardware
• Propellers and propeller shafts
• Military equipment
• Steam turbine condensers
• Oil coolers and auxiliary cooling systems
• Desalination plants

Hastelloy

These nickel-based alloys are resistant to corrosion caused by acids.

The following are types of Hastelloy nickel-based alloys:

• Hastelloy C-4 contains 14.5-17.5% chromium, 0-2% cobalt, 14-17% molybdenum, 0-3% iron, 0-1% manganese, and the remaining balance is nickel content. This alloy is mainly used in environments with inorganic acids. Inorganic acids are acids such as sulfuric acid and hydrochloric acid.
• Hastelloy C-22 contains 20-22.5% chromium, 0-2.5% cobalt, 12.5-14.5% molybdenum, 0-3% iron, 0-0.5% manganese, 2.5-3.5%, tungsten and the remaining balance is nickel content. This alloy is also resistant against acid corrosion.
• Hastelloy C-2000 contains 23% chromium, 2% cobalt, 3% iron, 16% molybdenum, and the remaining balance is nickel content. This alloy is mainly used in environments that contain aggressive oxidants.

Inconel Alloy

Inconel alloys are primarily composed of nickel, with chromium as the second most prevalent element. These alloys are known for their resistance to corrosion and oxidation, making them ideal for extreme environments where high stresses are encountered. However, Inconel alloys can be challenging to machine and shape.

Several types of Inconel alloys are available, including the following:

• Inconel 617 contains nickel, cobalt, chromium, and molybdenum. This combination results in an alloy that has improved strength and oxidation resistance. It‘s corrosion resistant even when exposed to highly corrosive environments. It‘s used in making ducting, transition liners, petrochemical processing, heat-treating equipment, production, and gas turbines.
• Inconel 601 contains nickel, iron, and chromium. Its properties include high corrosion resistance, high strength, and it‘s readily welded and machined. It also has high temperature resistance. Its main uses are in fabrication combustion chambers, thermal reactors, insulating cans, and refractory cans.
• Inconel 625 contains 58% nickel, 20-23% chromium, 5% iron, 8-10% molybdenum, 3.15-4.15% niobium, 1% cobalt and trace amounts of sulfur, manganese, aluminum, titanium, silicon, carbon, and phosphorus. It‘s mainly used in steam liner bellows, sheathing for undersea communication cables and some submarine components.
• Inconel 600 contains 72% nickel, 14-17% chromium, 6-10% iron, 1% manganese and trace amounts of carbon, sulfur, silicon, and copper. Its uses include but are not limited to chemical and food processing, heat treating, phenol condensers, soap manufacture, vegetable, and fatty acid vessels. It doesn‘t react with chlorine and chlorine water.
• Inconel 718 contains 50-55% nickel, 19% chromium, 17% iron, 3% molybdenum, 5% niobium, 1% cobalt, 1% aluminum and trace amounts of boron, phosphorus, sulfur, carbon, copper, titanium, manganese, and silicon. Uses include but are not limited to power generating plants, gas turbines, chemical production, combustion cans, and ducting.

Invar Alloy

This nickel-iron alloy is known for its low coefficient of thermal expansion. It is composed of 36% nickel and 64% iron.

Its primary applications include:

• Precision instruments
• Clocks
• Seismic creep gauges
• Television shadow-mask frames
• Valves in engines
• Large aerostructure molds

Kovar Alloy

This alloy comprises iron, nickel, cobalt, and small amounts of manganese, silicon, and carbon. Notably, it has a low coefficient of thermal expansion, meaning it experiences minimal expansion as temperature increases.

It is primarily used for glass-to-metal seals in scientific equipment, as well as conductors in vacuum tubes, X-ray tubes, microwave tubes, and light bulbs.

Monel Alloy

This alloy consists of 52 to 67% nickel, along with copper and small amounts of manganese, iron, carbon, and silicon. It is known for its corrosion resistance, malleability, low coefficient of thermal expansion, and high strength.

Uses of monel include but are not limited to:

• Seawater valves, strainer baskets, trolling wire, fixtures and fasteners
• Gasoline tanks, off-shore oil rigs, petroleum stills, processing equipment
• Musical instruments such as trumpets, French horns, tubas, and bass guitar strings
• Kitchen sinks, doorknobs, and decorative screens
• Boilers, chemical tanks, tubes, wires, sheets and plates that are used in the manufacturing of equipment, and parts

Various types of Monel alloys are available, including the following:

• Monel 400 contains 63% nickel, 28-34% copper, 2.5% iron, 2% manganese and trace amounts of sulfur, carbon, and silicon.
• Monel 404 contains 52-57% nickel, 2% iron, 45% coppers and trace amounts of aluminum, manganese, silicon, carbon, and sulfur. Mainly used in the electronics industry due to its low permeability.
• Monel 405 has the same composition as Monel 400. Its main uses are in the chemical, marine, and oil industries. It‘s also used in pickling bat heating coils, making steam generator tubing, and brine heaters. This alloy is corrosion resistant, slightly magnetic at room temperature, resistant to both hydrofluoric and hydrochloric acids and is resistant to steam at high temperatures as well as seawater.
• Monel K-500 contains 64% nickel, 30% copper, 1% iron, 2.8% aluminum and trace amounts of carbon, titanium, and manganese. It‘s mainly used in marine equipment. This is because Monel K-500 is very resistant to the corrosive nature of seawater elements.

Nichrome Alloy

This nickel-chromium alloy is known for its high electrical and temperature resistance, and it has a silvery-gray appearance. It is primarily used as resistance wire, in heating elements for appliances like space heaters and toasters, and in dental restorations.

It is also employed in the explosives and fireworks industry as a bridgewire for electric ignition systems, including electric matches and model rocket igniters. Additionally, it finds applications in ceramics, flame testing, and motorcycle mufflers.

Nickel 200

This is wrought nickel with a purity of approximately 99.6%, containing trace amounts of iron, manganese, silicon, copper, carbon, and sulfur.

Its applications include:

• Synthetic fibers
• Food processing equipment
• Drums to transport chemicals
• Rocket motors
• Piping
• Handling of foods
• Aerospace and missile components

Nickel Bars and Rods

Nickel rods and bars come in straight forms and various shapes, including square, circular, and triangular. They are primarily used in applications such as steam turbines in power plants and gas turbines in aircraft.

There are several types of nickel bars namely: nickel hex bar, pure nickel alloy round bar, ASTM B160 nickel alloy rod, and nickel alloy square bar to name just a few.

Nickel Plates

This form of nickel, produced by rolling, is used in the construction of buildings and bridges.

Nickel Sheet

This is a flat, thin plane made from nickel or nickel alloys, characterized by its uniform thickness.

Nickel sheets have various applications such as in the power generation, marine, electronics, and aerospace industry to name just a few.

Nickel Tubing

This is a hollow nickel tube, available in cylindrical or rectangular shapes, used for transporting fluids or gases and as components in various equipment.

Permalloy Nickel Alloy

Permalloy is a nickel alloy comprising 80% nickel and 20% iron. Known for its high magnetic permeability, it is commonly used as a magnetic core material in electrical and electronic devices and for magnetic shielding to block magnetic fields.

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Chapter 3: What are the application and benefits of Nickel Metal?

This chapter will explore the various applications and advantages of nickel metal.

Applications of Nickel Metal

As previously mentioned, nickel is a versatile metal with numerous applications. These uses are summarized in the list below:

• The main important application of nickel is as an alloying metal. It can combine with metals such as iron, copper, chromium to name just a few in order to form alloys that are high temperature resistant, corrosion resistant, have a low coefficient of thermal expansion, excellent ductility, great tensile strength, are malleable, and have good electrical conductivity. All these properties prove useful in the construction and production of various equipment and products used in industry and households.
• It‘s useful for making stainless steel.
• Nickel alloys are used in the aviation, marine, chemical, and energy industries.
• Products such as color TV sets, communication sets, surgical instruments, combustion chambers, turbine engine disks are all made from nickel and nickel alloys.
• Nickel is used in electroplating. This is done to prevent or slow down the corrosion of other metals as well as for decorative reasons.
• It‘s also used in the making of rechargeable battery systems that are essential in power tools, transport, and emergency power supply.
• Nickel also acts as a catalyst in several important chemical reactions such as the hydrogenation of vegetable oils, reforming of hydrocarbons, and production of fertilizers, pesticides, and fungicides.
• Because of its corrosion resistance, nickel was at times utilized as a replacement for decorative silver. Nickel was also at times utilized in some nations after 1859 as a cost effective coin metal, but it was replaced in the 20th century in later years, by cost effective stainless steel.
• Nickel naturally has a magnetic field presence meaning that it is a magnetostrictive material.
• Nickel is utilized as a binding agent in the hard metal industry or cemented tungsten carbide. It is utilized in 6% to 12% ratios by weight. Nickel causes the tungsten carbide to be magnetic and enhances resistance to corrosion to the cemented components, though the hardness is lower than for those featuring a cobalt binder.
• About 27% of all nickel manufactured is intended for engineering, 10% for construction and building, 14% for cylindrical products, 20% for metallic goods, 14% for transportations, 11% for electronic products, and 5% for other uses.

Benefits of Nickel Metal

Nickel is fully recyclable and plays a crucial role in building construction and in equipment used in power and communications industries, among others. Its durability, corrosion resistance, and hygienic properties make it valuable in the medical field. Pure nickel is rarely used on its own; it is usually alloyed with other metals to enhance ductility and strength at high temperatures.

Nickel's resistance to high temperatures reduces corrosion, allowing it to be used for extended periods without replacement. This makes it suitable for applications such as jet engines, offshore installations, and power generation facilities, where it endures extreme temperature conditions. Additionally, nickel is a key element in the stainless steel industry.

Drawbacks of Nickel Metal

Despite the many beneficial applications and favorable properties of nickel and its alloys, there are several drawbacks associated with these materials, which are outlined below:

• Touching nickel can result in contact dermatitis among individuals with sensitive skin types.
• Nickel occurs naturally and can only be obtained through mining, the negative consequences of mining include alteration of soil profiles, deforestation, contamination of local streams, increase in noise level and dust, and deforestation. Migratory routes of animals can be affected by the infrastructure built to support mining activities. Mining can reduce the living standards of people suited near the area where the mining activities occur.
• Laterite nickel ores require a vast amount of energy for the drying of moisture and removal of chemically bound water from the ores as a result these two major operations are very expensive to carry out.
• Since nickel is a metal it‘s difficult to fabricate as metal fabrication tools are expensive in comparison to plastic fabrication tools. In addition the processes that are carried out after the fabrication process, examples are finishing and painting, are expensive and time consuming. Furthermore metals are not ideal for creating complex designs.
• Nickel alloys such as Inconel are difficult to shape.

Maintenance When Using Nickel Metal

Nickel finishes, which are often electroplated onto metals like copper or brass, may tarnish over time due to exposure to chemicals, oils, cleaning products, acidic foods, and other substances. Harsh weather conditions can also contribute to tarnishing. To maintain nickel-plated items, use a mild soap and a soft cloth for cleaning. A water and vinegar solution can help remove dirt and oils, while bleach-based cleaners and abrasives should be avoided. Although nickel products are corrosion-resistant and do not rust, they require proper care to keep their appearance.

Conclusion

Nickel is a naturally occurring metallic element which belongs to the metal category known as transition metals. It has two types of ores namely: laterites and magmatic sulfide ores. An ore is a naturally occurring rock which contains one or more minerals that can be extracted, refined and then sold at a profit. The nickel is mined and extracted from the ores using two different methods. Open cut mining, a surface mining method, is used to mine the laterite ore. Laterite ores contain large amounts of water as moisture and hydroxides as a result a large amount of energy has to be used in the drying process and removal of the chemically bound water. Sulfide ores are extracted using underground mining techniques. The ore is crushed and selective floating is used to get some of the nickel from the ore and remove the waste. Magnetic separators are sometimes used as well. Both extraction and refinement of the two ores result in nickel matte, a substance which is a nickel-iron sulfide. Further refinement of the nickel matte can result in nickel with a purity of up to 95%.

Secondary manufacturing processes include casting, molding, separating, and forming. Nickel can be machined into a variety of shapes through processes such as nickel extrusion, cold drawing and Electroless nickel plating. The latter being the most common way to shape nickel. Nickel can be shaped into bars and rods, sheets, plates, tubes and many other shapes. The main use of nickel is in the making of nickel alloys.

Nickel alloys can be classified into the following categories namely: nickel-titanium alloys, nickel-chromium-cobalt alloys, nickel-chromium-molybdenum alloys, nickel-chromium-iron alloys, nickel-chromium alloys, nickel-molybdenum alloys, nickel-copper alloys, nickel-iron alloys, and wrought nickel. Nickel alloys all have different characteristics that make them suitable for a variety of applications.

Nickel is 100% recyclable and has many uses in the power, communications, marine, oil, and medical industries however it has its drawbacks. The most apparent drawback comes from the fact that mining is the only method that can be used to obtain the nickel ore of which mining is harmful to the environment. Furthermore, extracting nickel from laterite ore is expensive as a large amount of energy is required for the drying and smelting process. However nickel and nickel alloys remain an integral part of human civilization as products made from these substances are durable and can last for decades.

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