How to choose the optimal gasket material for sulphuric acid service

When choosing a gasket material, applications involving sulphuric acid (H2SO4) can be particularly challenging. As a media, sulphuric acid is extremely corrosive and, unless the gasket material is chosen wisely, the risk of gasket failure with resulting leakage can be high. This blog provides guidance for choosing the optimal gasket material for sulphuric acid service.

When you need to choose a gasket material for sulphuric acid service, there are essentially three choices of gasket material to consider using. These are the following:

  1. Glass-filled skived Teflon®.
  2. Restructured manufactured Teflon®.
  3. Graphite with stainless steel inserts.

Selecting the right gasket material for sulphuric acid service from the above options will depend on a number of factors outlined below.

Glass-filled Teflon® is a good gasket material choice if your application operates at lower temperature ranges – for example, where operating temperatures are lower than 150°F. While glass-filled Teflon® is about half the cost, on average, of restructured sheet, the material is not without some disadvantages. The structure of glass-filled Teflon® will cause the sheet to creep and cold flow at elevated temperatures. Therefore, a careful evaluation of the maximum operating temperature should be made when considering this gasket material for sulphuric acid service. For more information on the properties of glass-filled Teflon® gasket material, please see our blog PTFE Gasket Material: Texolon 9406 PTFE Sheet.

Restructured manufactured sheet is now the preferred gasket material for sulphuric acid service where the operating temperature is less than 400°F. Restructured PTFE sheet will do an excellent job in these applications. The preferred choice of filler for restructured PTFE sheet for sulphuric acid applications is mineral silica.

Canada Rubber Group Inc. (CRG) supplies Tealon™ 1580 restructured PTFE gasket material for sulphuric acid service where the operating temperatures are  lower than 400°F. Tealon™ 1580, manufactured by Teadit North America, is a premium quality restructured sheet that is the exact equivalent of Gylon®. The unique manufacturing process for Tealon™ 1580 results in a sheet that has less creep and cold flow normally associated with PTFE gasket material.

Graphite gasket material manufactured with stainless steel inserts is the third gasket material that will successfully seal sulphuric acid applications. Graphite gasket material is capable of withstanding operating temperatures up to 850°F. A point to note is that if your application involves sulphuric acid in concentrations over 85 per cent, the gasket fabricator should be consulted for specific guidance on using graphite sheet as a gasket material for sulphuric acid service.

In summary, sulphuric acid is an aggressive chemical which is hazardous to health and safety.  Serious investigation and evaluation of the application operating conditions needs to be made to ensure that right gasket material is selected and used. Successfully sealing sulphuric acid applications need not be prohibitively expensive – quality gasket materials are available to service this demanding application.

CRG fabricates precision cut, high-quality, gaskets from premium sheet materials, including gasket materials for sulphuric acid service. We can custom manufacture gaskets from prototype and no order is too big or too small – we are equipped to handle mass production runs or small-lot orders equally well, and can provide rapid turnaround on urgent needs or emergency service. To find out how we can service your gasket needs, contact our sales department today at crg@canadarubbergroup.com.

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