Chemicals Corrosion Guide

When the information is available, the Corrosion Guide provides detailed corrosion data on the preparation of various chemicals. For example, in the section on sulphuric acid, the corrosion rates for several alloys are given when used at various stages of an actual process involving that acid. In the section on phosphoric acid, cognisance of the method of production shows also the influence of the minor constituents as well as the major chemical on the corrosion of various materials. Nevertheless, it must be emphasised that even a book as comprehensive as the Corrosion Guide can only cover a limited number of all the possible chemicals used in practice. 

Various ceramic membranes, for example, possess differing degrees of acid/base resistance, depending on the pH value, particular phase of the membrane material, porosity, contact time and temperature. However, no quantitative data are available on the kinetics of chemical dissolution of ceramic membranes as a guide for chemical corrosion considerations. 

Greene R W (ed) 1986 The Chemical Engineering Guide to Corrosion (New York McGraw-Hill)... 

Although the Langelier index is probably the most frequently quoted measure of a water s corrosivity, it is at best a not very reliable guide. All that the index can do, and all that its author claimed for it is to provide an indication of a water s thermodynamic tendency to precipitate calcium carbonate. It cannot indicate if sufficient material will be deposited to completely cover all exposed metal surfaces consequently a very soft water can have a strongly positive index but still be corrosive. Similarly the index cannot take into account if the precipitate will be in the appropriate physical form, i.e. a semi-amorphous egg-shell like deposit that spreads uniformly over all the exposed surfaces rather than forming isolated crystals at a limited number of nucleation sites. The egg-shell type of deposit has been shown to be associated with the presence of organic material which affects the growth mechanism of the calcium carbonate crystals . Where a substantial and stable deposit is produced on a metal surface, this is an effective anticorrosion barrier and forms the basis of a chemical treatment to protect water pipes . However, the conditions required for such a process are not likely to arise with any natural waters. 

In the polyacrylic synthetic fibre industry, carbonitrided molybdenum guides have been used in place of chromium plated steel because of their resistance to corrosion and erosion. Chemicals that attack molybdenum are listed in Table 5.9. 

Swandby, R.K. Corrosion Charts Guides to Materials Selection, Chemical Engineering, Nov. 12, 1962, p. 186. 

Most reactions are violent. Accidental contact with a number of organics and inorganic substances may present a fire or explosion hazard. Rapid mixing with water can be explosive. The compound is highly corrosive. Skin contact can cause a severe burn. Vapors are highly irritating to eyes, nose and mucous membranes. (Patnaik, P. 1999. A Comprehensive Guide to the Hazardous Properties of Chemical Substances, 2nd. New York John Wiley Sons.)... 

For detailed information about lead linings, their physical properties, and chemical resistance, the reader is referred to Lead for Corrosion Resistant Applications A Guide, published by the Lead Industries Association, Inc., New York, NY. 

Some common chemicals have been tested for the skin corrosion under DOT protocols at a variety of concentrations. The results of this study can be used as a guide when classifying some of these materials. It must be remembered that the responsibility of determining if a material belongs to a hazard class rests with the shipper and that the use of published data should only serve as a guideline. 

---