Catalyst Gauze

In 1990 Johnson Matthey developed knitted technology as an alternative to woven technology. The introduction of this technology changed the industry with the advantage of better metal distribution and a greater surface area resulting in increased conversion efficiency.

Since then Johnson Matthey have developed a wide range of knitted products to meet the individual needs of each plant and can also offer a tailored pack utilising a number of the Inter-LoK products to produce the best solution for the plant. Details of the individual gauze structures forming the Inter-LoK range can be found in the related product area. However, if you can not find the information you require please feel free to contact us directly.


This knitted product was originally developed for plants requiring gauzes with increased strength and flexibility. The increased surface area ensures optimum performance and the structure improves handling. Nitro-LoK is primarily for use in medium and high-pressure plants.

Nitro-LoK Datasheet DOWNLOAD PDF


Pro-LoK was developed to meet the needs of low pressure and atmospheric plants wanting the benefits of knitted technology. Pro-LoK reduces the open area and increases the surface area in order to increase contact time and hence conversion efficiency.

Pro-LoK / Pro-Lite Datasheet DOWNLOAD PDF


Hi-LoK was primarily introduced for high pressure plants to give increased strength at elevated temperatures. The open area is lower than the other knitted gauzes resulting in increased metal – gas contact time.



Pro-Lite offers the same density as Pro-LoK but with an increased wire diameter, offering low pressure plants the option of increasing the wire diameter but without increasing the intrinsic costs.

Pro-LoK / Pro-Lite Datasheet DOWNLOAD PDF


Introduced as a result of the growing economic pressure on plants with the increasing costs of PGMs. Eco-Cat introduces high palladium gauzes into the pack to reduce the platinum inventory but maintain conversion efficiency.

Eco-Cat Datasheet DOWNLOAD PDF

Eco-Cat Reference List DOWNLOAD PDF


Tailored catalyst packs were introduced in 1997 to provide plants with the best possible solution and as a result optimise their product. Analysis (SEM, ICP and weight loss) of current gauze packs can help to determine which gauzes have performed the highest level of ammonia oxidation meaning metal weight can be distributed accordingly for subsequent packs. Analysis of other factors is also taken into account – see other services. Please note this is not a one off process, but continual development and improvement can be undertaken with plants to ensure the optimum performance for the conditions is achieved.

Tailoring Datasheet DOWNLOAD PDF


The HICON pack uses a corrugated design to optimise conversion efficiency, pressure drop, and campaign length by increasing the effective surface area of each individual gauze. Although the major benefits are seen in high pressure/high nitrogen loading nitric acid plants it can also be considered for medium pressure plants as well as Cyanide applications.


Hydrogen Cyanide

Hydrogen Cyanide (HCN) is primarily produced in industry by the Andrussow Process. The process reacts methane and ammonia in air over Pt-Rh gauzes at high temperatures (1100°C). The desired reaction can be simplified to:

The synthesis of HCN is a fast reaction catalysed by the Pt-Rh gauzes, and the rate limiting step is the transport (mass transfer) to and from the metal. As a result of this fact it is important that the gauzes used do not inhibit this mass transfer and where possible increase the diffusion rate through the boundary layer.

Johnson Matthey can supply a range of knitted products to meet the requirements of HCN industry to ensure that the diffusion rate through the boundary layer is not inhibited. Alongside the standard knitted products Johnson Matthey can offer the activation of HCN gauzes and HICON corrugated gauze packs.



Caprolactam is primarily used in industry for the production of nylon 6 / polyamide fibres and resins. Caprolactam can be produced by many methods but on an industrial scale most methods use cyclohexanone that is converted to the oxime following a reaction with hydroxylamine and finally the oxime is converted caprolactam by a Beckmann Rearrangement reaction.

Johnson Matthey can work with the individual caprolactam plants to provide a tailor made solution to meet the specific needs.

Caprolactam Datasheet DOWNLOAD PDF