Caustic soda tank

Lime Soda. Process. Lime (CaO) reacts with a dilute (10—14%), hot (100°C) soda ash solution in a series of agitated tanks producing caustic and calcium carbonate. Although dilute alkaH solutions increase the conversion, the reaction does not go to completion and, in practice, only about 90% of the stoichiometric amount of lime is added. In this manner the lime is all converted to calcium carbonate and about 10% of the feed alkaH remains. The resulting slurry is sent to a clarifier where the calcium carbonate is removed, then washed to recover the residual alkaH. The clean calcium carbonate is then calcined to lime and recycled while the dilute caustic—soda ash solution is sent to evaporators and concentrated. The concentration process forces precipitation of the residual sodium carbonate from the caustic solution the ash is then removed by centrifugation and recycled. Caustic soda made by this process is comparable to the current electrolytic diaphragm ceU product. 

Sodium borobydride is available as a 12% solution in caustic soda and in soHd form either as powder or pellets (3). The predominant form produced is the solution, the DOT shipping classification for which is corrosive Hquid. Forms of packaging are 18.9-L pails, 208.2-L dmms, and either tank tmck or tank car for bulk shipments. 1991 pricing for the solution form was 40.34/kg of borobydride contained. SoHd sodium borobydride, a white powder packaged in polyethylene bags in metal containers, was priced at 48.39/kg. 

Electrochemical corrosion protection of the internal surfaces of reaction vessels, tanks, pipes and conveyor equipment in the chemical, power and petroleum industries is usually carried out in the presence of strongly corrosive media. The range stretches from drinking water through more or less contaminated river, brackish and seawater frequently used for cooling, to reactive solutions such as caustic soda, acids and salt solutions. 

Cathodes made of steel tube rings 10 m in diameter are used m the internal protection of several 30-m-high caustic soda stirring tanks, each with a surface area of 3100 m, The cathodes were insulated and mounted on supporting brackets. The current supply was via armored parallel connected cables. One-inch bolts were used for the entrance in the tank wall as shown in Fig. 21 -13 for a feed current of 500 A. The size of the cathodes has to be such that they can maintain sufficient cathodic protection current. The surface ratio of the object to be protected and the... 

The resultant yellow sodium cellulose xanthate is dispersed in an aqueous caustic soda solution, where some hydrolysis occurs. This process is referred to as ripening and the solution as viscose . When the hydrolysis has proceeded sufficiently the solution it transferred to a hopper from which it emerges through a small slit on to a roller immersed in a tank of 10-15% sulphuric acid and 10-20% sodium sulphate at 35-40°C. The viscose is coagulated and by completion of the hydrolysis the cellulose is regenerated. The foil is subsequently washed, bleached, plasticised with ethylene glycol or glycerol and then dried. 

Storage tanks for liquid caustic soda should be provided with an air vent for gravity flow. The storage capacity should be equal to 1.5 times the largest expected delivery, with an allowance for dilution water, if used, or two-weeks supply at the anticipated feed rate, whichever is greater. Tanks for storing 50 percent solution... 

The first vessel in the blowdown system is therefore an acid-hydrocarbon separator. This drum is provided with a pump to transfer disengaged acid to the spent acid tank. Disengaged liquid hydrocarbon is preferably pumped back to the process, or to slop storage or a regular non-condensible lowdown drum. The vented vapor stream from the acid-hydrocarbon separator is bubbled through a layer of caustic soda solution in a neutralizing drum and is then routed to the flare header. To avoid corrosion in the special acid blowdown system, no releases which may contain water or alkaline solutions are routed into it. 

Fortunately in this case the two materials did not react. People who have emptied acid into alkali tanks have been less fortunate. A plant received caustic soda in tank cars and acid in tank trucks. One day a load of caustic soda andved in a tank truck. It was labeled Caustic Soda, the delivery papers said it was caustic soda, and the hose connections were unusual. But the operators had a mind-set (see Section 3.3.5) that anything in a tank truck was acid, and they spent two hours making an adaptor to enable them to pump the contents of the tank truck into the acid tank. 

Vessels are sometimes contaminated by material left over from a previous use. For example, tank trucks were filled with a waste sludge containing particles of aluminum. One day the tank truck contained some caustic soda left over from the previous load. The caustic soda reacted with the aluminum, producing hydrogen. The increase in pressure blew open an inspection port and knocked an operator onto the ground. 

Soda-ofen, m. soda furnace, black-ash furnace, -riickstande, m.pl. soda residues, tank waste (in the Leblanc process), -salz, n. soda salt (sodium salt), specif, sodium carbonate, -schmelze, /. black ash. -see, m. soda lake, -seife, /. soda soap, -stein, m. caustic soda, -wasser, n. soda water, -zahl, /. soda number. 

Gold is stable in most strong reducing acids, whereas iron corrodes rapidly, yet finely divided gold can be quickly dissolved in oxygenated cyanide solutions which may be contained in steel tanks. A mixture of caustic soda and sodium nitrate can be fused in an iron or nickel crucible, whereas this melt would have a disastrous effect on a platinum crucible. 

Correction of pH level via caustic soda (after the degasser and before the BX) is standard practice. Because both acid regeneration and caustic pH correction are practiced, it is usual to isolate the plant from the mains by providing a break tank. The full plant therefore tends to be break tank, RW booster pump, acid measuring tank, WAC, degasser, degassed water booster pump, pH correction, and BX. A schematic layout of this type of plant is shown in Figure 9.3a. 

The aluminum hydroxide crystals settle to the tank bottom, and are removed. The crystals are then washed to remove any caustic soda residues, vacuum dewatered, and sent on for calcination. In the calciners (a type of rotating kiln) the aluminum hydroxide is roasted for further dewatering. 

Limestone is the cheapest basic product (0.20/lb in 1968 0.40/kg). However, it can become coated with calcium sulfate, which can almost stop neutralization from occurring. Some kind of scouring may be necessary to prevent this. Lime may be used, but it also can become coated and rendered ineffective. Soda ash and caustic soda are other alternatives, but they cost 8 to 10 times as much as limestone.35 Sometimes limestone or lime is used to raise the pH to between 4.0 and 5.0, and the more expensive but more easily controllable soda ash or caustic soda is used to obtain the desired final pH. The only equipment needed is storage tanks for the acids and bases and mixing tanks, equipped with the proper controls. 

A detailed supply-chain model, which showed that two days inventory was required to supply the forecast market demand, determined chlorine storage tank number and size. The minimum number of drums and cylinders of liquid chlorine required to be held on-site was also calculated from the supply-chain model. This approach was also extended to calculation of the number and size of storage tanks for products such as caustic soda, sodium hypochlorite and hydrochloric acid. 

Both scrubbers will be supplied with three sources of electrical power - the main grid supply, a back-up grid supply from a different substation and an emergency diesel generator. In the emergency chlorine scrubber, critical equipment items will be backed-up by automatic start-up of stand-by equipment. A gravity head tank of caustic soda and a nitrogen ejector will also be provided to allow safe neutralisation of chlorine vents in the event of total power failure. 

The annular space in the tank H is filled with water, hile the interior of the tank is filled with a 10 per cent lution of caustic soda in distilled water. 

The first step of the process is performed in a separate, dedicated building. The drums of arsenic trioxide are opened in an air-evacuated chamber and automatically dumped into 50% caustic soda. A dust collection system is used. The drums are carefully washed with water, the washwater is added to the reaction mixture, and the dmms are crushed and sold as scrap metal. The intermediate sodium arsenite is obtained as a 25% solution and is stored in large tanks prior to further reaction. In the next step, the 25% sodium arsenite is treated with methyl chloride to produce the disodium salt DSMA (disodium methanearsenate, hexahydrate). This DSMA can be sold as a herbicide however, it is more generally converted to MSMA, which has more favorable application properties [8]. 

The monomers are piped from the tank farm to the caustic soda scmbbers where the inhibitors are removed. Soap solution, catalysts, and modifiers are added to produce a feed emulsion which is fed to the reactor train. Fewer reactors are normally used than the number required for a cmmb product line. When polymerization is complete, the latex is sent to a holding tank where stabilizers are added. 

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