Rubber lining hydrochloric acid

Plastics and Elastomers. Common plastics and elastomers (qv) show exceUent resistance to hydrochloric acid within the temperature limits of the materials. Soft natural mbber compounds have been used for many years as liners for concentrated hydrochloric acid storage tanks up to a temperature of 60°C (see Rubber, natural). SemUiard mbber is used as linings in pipe and equipment at temperatures up to 70°C and hard mbber is used for pipes up to 50°C and pressures up to 345 kPa (50 psig). When contaminants are present, synthetic elastomers such as neoprene, nitrile, butyl. 

Hydrochloric Acid, 32% (Alternate) Rubber Lined C. Iron Hard Rubber Carbon Steel Rubber or Plastic Ring Packing... 

These same types of compounds are also more resistant to many acids at high temperatures than natural rubber can handle. Neoprene should not be used in parts which are bonded to metal for hydrochloric acid service because acid migration can cause failures. For hydrochloric acid service ebonite lined mild steel equipment is the correct selection. Ebonites form rubber hydrochloride film in contact with natural rubber and this film is the protective layer against corrosion. 

In spite of the unsaturation of rubber it is said to be resistant to chemical attack since a few chemical derivatives like chlorinated rubbers, cyclised rubbers and chlorides are formed as protective layers retarding further attack by the chemicals. Properly compounded vulcanizates satisfactorily resist the action of most inorganic acids other than oxidizing acids such as nitric, hydrochloric and sulphuric acids. Rubber linings which are to resist swelling to a lower degree should be "tightly" vulcanized. 

The materials handled in the bins were 20% solids by weight, flow of 2.9 tons of water per hour and 47 gallons/minute of pulp. The size of the material was 100 to plus 325 BSS mesh. Maximum acid concentration was 20% hydrochloric acid. The temperature in the system was 60°C. A 6 mm thick natural rubber lining of shore hardness 50°A was used to protect the equipment against the abrasive environment as well as the corrosion effects of hydrochloric acid. 

Illmenite sand with steam and hydrochloric acid was handled in the spherical digesters. The temperature in the digesting process was ambient to more than 130°C. Therefore brick lining was applied on a butyl rubber lining 5 mm thick with hardness of 55°A. The rubber serves as a cushioning medium beneath the brick lining, as well as resisting the temperature at the brick rubber interface of about 100°C. 

Six hundred milliliters of concentrated hydrochloric acid (7.2 mols) is placed in the drying tower. A concentrated solution of 103.5 g. of sodium nitrite (1.5 mols) in approximately 150 ml. of water is placed in the dropping funnel. The dropping funnel is fitted with a two-hole rubber stopper, which is connected to an air line and to a manometer K. The solution of sodium nitrite is kept under a pressure of 100 mm. to ensure its flow into the hydrochloric acid and to prevent bubbles of nitrosyl chloride from backing up into the dropping funnel. The receiver I is surrounded with a mixture of solid carbon dioxide and acetone. 

Two fairly large dished head low-pressure 32-percent hydrochloric acid tanks supplied a periodic flow of acid to a chemical process in an open-air plant in the sunny southern United States. (See Figure 6—15.) The two rubber-lined, horizontal storage tanks were 12 ft. (3.7 m) in diameter and about 40 ft. (12.2 m) in length. A small vent scrubber that used water absorption for any fumes during the filling operation, served both acid tanks. 

The daily output of a cooler measuring 1650 X 610 X 350 mm and an absorber measuring 1650 X 970 X 350 mm equals 7.5 tons of 30 to 35 per cent hydrochloric acid. As a rule, two graphite absorbers are connected in series and the more diluted acid from the second absorber which contains about 20 per cent HC1 is pumped into the first absorber. The rest of the unabsorbed gas is led through a rubber lined steel absorption tower into the atmosphere. The tower is sprayed with water and the diluted acid obtained is employed as an absorption liquid in the second igurite absorber. The flow of the tail gases is aided by a steam-jet ejector. 

Hydrochloric acid is stored in rubber lined steel storage tanks and shipped in rubber lined tank cars, pot cars or glass carboys. The following commercial grades of hydrochloric acid are known synthetic hydrochloric acid which is prepared by the reaction of hydrogen with chlorine sulphate acid obtained as a by-product in the manufacture of sodium sulphate hydrochloric acid used in the foodstuff industry and finally chemically pure hydrochloric acid. 

Natural and synthetic rubbers are used as linings or as structural components for equipment in the chemical industries. By adding the proper ingredients, natural rubbers with varying degrees of hardness and chemical resistance can be produced. Hard rubbers are chemically saturated with sulfur. The vulcanized products are rigid and exhibit excellent resistance to chemical attack by dilute sulfuric acid and dilute hydrochloric acid. 

Synthetic resins, such as Bakelite, Pollapas, Cibanite, and similar materials, are used only for special purposes, since their mechanical strength is generally quite low. Hard rubber is a better material, and can be used also for concentrated hydrochloric acid lines. 

The outstanding property of rubber in general is resilience, or low modulus of elasticity. The flexibility and physical properties of rubber account for its application in general engineering and automobile industries whereas its chemical, wear and abrasion resistance as a sacrificial material, plus its insulating properties are utilised in many corrosion and erosion applications in process industries. Rubber lined mild steel, pipes and tankages have been standard materials of construction for hydrochloric acid service for many years. 

When there is a relative motion between the corroding liquid and the metal or rubber surface the rate of attack of the damage to the surface is increased. The process is called sweating off with the corrosion product thus exposing the base surface again to corrosion. Otherwise the corrosion product (as a newly formed protective layer) would have prevented or slowed down further corrosion, just as in the case of hypochlorous acid solution on natural rubber lining, where the protective corrosion products exhibit very low cohesion and as such prone to be wiped off by the liquid unlike wet chlorine or hydrochloric acid which form a strong layer of corrosion product well adhered to the rubber surface. 

For zinc oxide at, for example, levels of 15 to 45 phr, good filler dispersion is essential for better dimensional stability in calendered sheets. Butyl sheets are used in storage tanks, digesters and other large equipment handling phosphoric acid, hydrochloric acid and sulfuric acid very effectively in fertiliser and chlor-alkali plants. When high temperatures are encountered, carbon bricks or acid resistant bricks are lined over the rubber lining. 

For a good quality rubber lining compound to be used with 20% hydrochloric acid, the curve (of item 1) should be as near to the X axis as possible, i.e., it should have a low slope. Similarly, for the same quality of rubber lining (of item 2) the curve will exhibit a rise in the beginning but later on, it should fall off rapidly. It can be noted here that Ruthner has not specified any absolute reference value, so that one could compare compounds on the same basis. 

By means of suction the charge is drawn into another brick-lined vessel containing 5,000 liters 60°B6 sulfuric acid at 20°C. The stirred slurry of dianisidine sulfate is filtered, and the press cake (after washing with 50 per cent sulfuric acid) is delivered to a 20-cu m wooden tub containing water and made up to 11,000 liters. Now 500 liters of 33 per cent hydrochloric acid is added, and the contents are heated to 95°C by means of a rubber-covered steam leg to dissolve the dianisidine hydrochloride. About 1,000 liters of 2 per cent sodium sulfide solution is introduced to precipitate any residual zinc. After the addition of 25 kg Terrana (a type of mineral filter aid), the charge is permitted to settle. The supernatant liquor is drawn off into the brick-lined precipitation kettle, where 900 kg salt is added, and allowed to cool to 20°C (no coil) to precipitate the hydrochloride of o-dianis-idine. The charge is filtered, and the press cake is washed twice with saturated salt solution. The product is dried on enamel trays at 60 C in air or vacuum. The yield is 75 per cent of theory, about 15-20 per cent diphen-... 

Bubject to wear on pumps, agitators, etc. In dilute solutions, wood is aatisfactory where conditions allow it to swell and seal pores, cracks, etc. Care must be taken that hoops, tie rods, etc., are coated with an inert material such as tar, pitch, silicates, epoxy and polyester resins, polyvinyl chloride, etc. For hydrochloric acid, rubber-lined steel is excellent at low... 

Rubber linings are used for strong acids (concentrated hydrochloric and phosphoric acid). For extremely aggressive concentrated nitric acid, the entire tank car body is made from stainless steel (316L). 

Rubber linings are often used in handling strong acids such as hydrochloric and phosphoric acids. In the case of extremely aggressive nitric acid, the entire tank body is made of type 316L stainless steel. 

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