Corrosive substance

Corrosive substances destroy the skin and can produce necrosis. Although there is only one danger symbol, a corrosive property must be distinguished from a very corrosive property by the use of different R-phrases. The following time-dependent differences exist  

Skin damage after a reaction time of 4 h R 34 Skin damage after a reaction time of 3 min R 35 

As the corrosive property is correlated with the pH, the following pH ranges show in general a corrosive effect and preparations have to be classified as corrosive in accordance with Preparation Directive 1999/45/EC [3-2]  

In general the corrosive reaction of bases is much stronger than that of acids. 

Hydrogen chloride Hydrogen fluoride Phosphoric acid Phosphorus trichloride 

Recommendations define corrosive substances as substances which, by chemical reaction, will cause severe damage when in contact with living tissue, or, in the case of leakage, will materially damage, or even destroy, other goods or the means of transport, J 1. With respect to evaluation methods for these substances, please refer to technical books specializing in the subject. 

In the first instance, all corrosive chemical substances must be clearly labeled with the correct chemical name. Corrosive chemical substances include strong acids, bases and alkalis, dehydrating agents, halogens, organic halides, esters, and many 

Other substances. The concentrations of acids and bases and alkalis could be listed as follows acetic acid 25% concentration, hydrochloric acid 25% concentration, nitric acid 20% concentration, chromic acid, hydrofluoric acid, perchloric acid 10% concentration, sulfuric acid 15% concentration, fuming sulfuric acid, ammonium hydroxide 35% by weight of gas, potassium hydroxide (caustic potash), sodium hydroxide 5% concentration, aluminum chloride, bromine, phosphorous trichloride, potassium bifluoride, sodium hypochlorite 10% concentration, and zinc chloride. 

Some dehydration reactions of sulfuric acid can be very vigorous. For example, the reaction with perchloric acid produces unstable CI2O7, and a violent explosion can result. Concentrated sulfuric acid produces dangerous or toxic products with a number of other substances such as toxic carbon monoxide (CO) from reaction with oxalic acid, H2C2O4 toxic bromine and sulfur dioxide (Bf2 and SO2) from reaction with sodium bromide, NaBr and toxic, unstable chlorine dioxide (CIO2) from reaction with sodium chlorate, NaClOj. 

Contact with sulfuric acid causes severe tissue destruction resulting in a severe burn that may be difficult to heal. Inhalation of sulfuric acid fumes or mists damages tissues in the upper respiratory tract and eyes. Long-term exposure to sulfuric acid fumes or mists has caused erosion of teeth. 

Hydrogen peroxide, HjOj Interhalogen compounds such as OF and BrF3 Halogen oxides such as OFj, QjO, and QjO, Elemental fluorine, chlorine, and bromine (F2, CI2, Br2) 

Strong acid and strong oxidizer, corrodes metal, and reads with protein in tissue to form yellow xanthoproteic add lesions are slow to heal 

Strong acid, corrodes metals, and gives off HCl gas vapor, which can damage respiratoy tract tissue 

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Little is known of the market for acetyl chloride. The production and sales are beUeved to be small, but may have potential for very large scale-up. The total U.S. market may amount to only 500 t annually. Acetyl chloride must be shipped in polyethylene-lined dmms having capacities of only 220 L it must be labeled as a corrosive substance. Acetyl chloride generated captively from purchased raw materials probably has a unit value of no more than 0.92—0.95/kg. Shipping costs and other factors set the price at about 3/kg for the commercial trade. 

Corrosion Inhibitors. A corrosion inhibitor is any substance that effectively decreases the corrosion rate when added to an environment. An inhibitor can be identified most accurately in relation to its function removal of the corrosive substance, passivation, precipitation, or adsorption. 

Deaeration (mechanical or chemical) removes the corrosive substance—oxygen. 

In addition to films that originate at least in part in the corroding metal, there are others that originate in the corrosive solution. These include various salts, such as carbonates and sulfates, which may be precipitated from heated solutions, and insoluble compounds, such as beer stone, which form on metal surfaces in contac t with certain specific products. In addition, there are films of oil and grease that may protect a material from direct contact with corrosive substances. Such oil films may be apphed intentionally or may occur naturally, as in the case of metals submerged in sewage or equipment used for the processing of oily substances. 

Deposits cause corrosion both directly and indirectly. If deposits contain corrosive substances, attack is direct interaction with the aggressive deposit causes wastage. Shielding of surfaces below deposits produces indirect attack corrosion occurs as a consequence of surface shielding provided by the deposit. Both direct and indirect attack may involve concentration cell corrosion, but indirect attack almost always involves this form of corrosion. 

First, greases and oils serve as binders that accumulate and hold large amounts of potentially corrosive substances. Second, greases and... 

A non-corrosive substance which, through immediate, prolonged or repeated contact with the skin or mucous membrane, can cause inflammation. 

H8 Corrosive substances and preparations which may destroy living tissue on contact... 

Blowdown drum materials must be adequate for any corrosive substance that may be released into it, and for the temperamre limits defined. 

Textile applications Much use has been made of non-molybdenum Cr-Ni steels in dyeing. On the other hand, many dyeing solutions contain chlorides or other corrosive substances such as formic acid, and here it is often wiser to use the 316 group. 

This is the one example in which metal is not the substrate. Corrosion takes on a new meaning the coating here is required to protect the substrate from direct attack by corrosive substances, from water to more powerful household or industrial chemicals, such as grease, alcohols and bleach. We are concerned with the industrial application of thin protective layers to paper (e.g. labels), card (e.g. playing cards) and many wooden articles, including industrially finished doors, window frames and, particularly, furniture. 

An advantage of filming amines over neutralising amines is their relative independence of the concentration of corrosive substances. About l-2mg/kg of filming amine are usually adequate. This non-stoichiometric... 

The nurse must not give an emetic when a corrosive substance (such as lye) or a petroleum distillate (paint thinner, kerosene) has been ingested. In many cases of poisoning, it is preferable to insert a nasogastric tube to empty stomach contents. Emetics are used with great caution, if at all, when the substance ingested is unknown or in question. An emetic is never given to a patient who is unconscious or semiconscious because aspiration of vomitus may occur. 

In extreme cases irritant chemicals can have a corrosive action. Corrosive substances can attack and weaken materials of construction, as mentioned in Chapter 3. They can also attack living tissue (e.g. to cause skin ulceration and in severe cases chemical burns), kill cells and possibly predispose to secondary bacterial invasion. Thus while acute irritation is a local and reversible response, corrosion is irreversible destruction at the site of the contact. The outcome is influenced by the nature of the compound, the concentration, duration of exposure, the pH (see Figure 4.1) etc. Thus dilute mineral acids may be irritant whereas at higher concentrations they may cause corrosion. 

Gaseous nitrogen dioxide is a brown, paramagnetic, non-flammable, toxic, strongly oxidizing, corrosive substance shipped in approved, low-pressure steel cylinders. It is prepared in situ by heating lead nitrate ... 

Substances, which after short exposure can cause serious effects that are likely to be irreversible, even if prompt medical treatment is undertaken. People who have been exposed need to be kept away from these. Also included in this category are materials which give highly toxic combustion substances and corrosive substances. 

The term corrosion fatigue is used to describe the premature failure of materials in corrosive environments caused by cyclic stresses. Even mildly corrosive conditions can markedly reduce the fatigue life of a component. Unlike stress corrosion cracking, corrosion fatigue can occur in any corrosive environment and does not depend on a specific combination of corrosive substance and metal. Materials with a high resistance to corrosion must be specified for critical components subjected to cyclic stresses. 

A substance which by chemic al ac tion will Corrosive substance... 

The result of skin contact with corrosive substances is usually obvious but the... 

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