Metal sulfides have a firm place in various industries. If you are new to them or are considering whether the sulfur compounds are an option for your business, here are five facts about metal sulfides to help you decide and take the next steps.
A true all-rounder
Metal sulfides are known to be particularly useful in analytical chemistry for the separation of cations. But they can also do a lot outside the classical laboratory situation. Their special properties and numerous variants make them true all-rounders with a wide range of possibilities.
Number 1: Metal sulfides occur in nature
Sulfides and thus also metal sulfides officially belong to the substance group of salts. These are always metal-sulfur compounds in the most diverse forms. These compounds can be produced in the laboratory – but are also partly found in nature. One of the probably best-known representatives is pyrite, a modification of iron(II) disulfide. The chemical composition of iron and sulfur in a ratio of 1:2 is also known as fool’s gold. Molybdenum (IV) sulfide also occurs in nature in the form of the mineral molybdenite. Other metal sulfides, such as tin (IV) sulfide, are found rather rarely and are mainly produced industrially by processing the starting materials under the corresponding chemical reactions.
Number 2: They have low solubility
Metal sulfides have the property of being only slightly soluble. At the same time, sulfides have a high reactivity with heavy metals. This combination of chemical properties makes them the ideal choice in the field of wastewater treatment. Heavy metal ions react with sulfur to form poorly soluble metal sulfides, which do not contaminate water any further. These are then simply removed and processed in the form of a resulting metal sulfide sludge. In this way, valuable resources can be recovered from industry, which is advantageous both economically and in terms of environmental protection. And the resulting end products can in turn be used by other companies for their products and processes: a win-win situation.
Number 3: Metal sulfides are an ideal lubricant
Metal sulfides in fine powder form are used in industry as lubricants. The particle size of the grains is usually between 1 and 100 micrometres. Molybdenum disulfide, for example, is added to lubricating oils and greases. The additive improves the lubricating effect. As a result, machine components such as engines and centrifuges have a longer service life. In addition, the risk of damage in the event of sudden oil loss is drastically reduced. In addition to mixing with solid and liquid lubricants, metal sulfides are also used in bonding. In this process of treating metal surfaces, corrosion protection is created by using the appropriate metal sulfide. The areas of application in which they are in demand as lubricants include, among others:
- Aircraft manufacture (turbines)
- High temperature applications
- Laboratory technology (ultracentrifuges)
As functional additives, they are not only used in sintered metals, but also in plastics and batteries.
Number 4: They reduce the manufacturing and maintenance costs of sintered parts
Lubricating and oiling complex or hard-to-reach components often drives up the cost and time required for maintenance – if it can be done successfully at all. Metal sulfides can significantly extend the necessary maintenance intervals by improving the lubricating effect, thereby reducing running costs. Even in certain manufacturing processes, the right sulfide can save costs through simplified work steps.
For example, manganese sulfide improves the machinability of sintered moulded parts. If the sulfide is added to the metal powder during sintering, the finished components can be drilled, milled or turned much more easily. This means that less time is needed for finishing the moulded parts. The production of large quantities in consistently high quality is no problem. This means that metal sulfides also have a firm place in powder metallurgy as a reliable partner for the best possible results.
Number 5: Metal sulfides can be individually optimised
The different metal sulfides can therefore take on the most diverse tasks – and even within the respective sulfide groups, different areas of application are possible. Very fine tin (IV) sulfide can be used as a colour pigment, but can also reduce the wear of stressed components. Bismuth sulfide is used as a component of fluxes for arc welding, but can also be found in brake linings and clutch facings as a friction material. Thanks to the development of multiphase metal sulfide compounds, more and more areas of application are being opened up for the metal sulfides and better and better results are being achieved.
Salts for all situations
If you are looking for new solutions for your company or for ways to optimise existing production processes, it is worth taking a closer look at metal sulfides. These salts are true all-rounders that have a wide range of applications. The prerequisite for successful use is reliable partners and suppliers who can offer you the best solution with chemical expertise and industry knowledge. This is the only way can you truly exploit the full potential of metal sulfides.