Sodium oxides

Demand for Caustic Soda Types. Approximately 99% of the sodium hydroxide produced in 1987 was 50% caustic solution (5). Higher concentrations require additional evaporation and therefore increased prices relative to the sodium oxide values. To obtain maximum value, users have learned to adapt manufacturing processes to the 50% caustic soda. 

Multicomponent Silicate Systems. Most commercial glasses fall into the category of sihcates containing modifiers and intermediates. Addition of a modifier such as sodium oxide, Na20, to the siUca network alters the stmcture by cleaving the Si—O—Si bonds to form Si—0-Na linkages (see Fig. 3c). 

Commercial Hquid sodium alumiaates are normally analyzed for total alumiaa and for sodium oxide by titration with ethylene diaminetetraacetic acid [60-00-4] (EDTA) or hydrochloric acid. Further analysis iacludes the determiaation of soluble alumiaa, soluble siHca, total iasoluble material, sodium oxide content, and carbon dioxide. Aluminum and sodium can also be determiaed by emission spectroscopy. The total iasoluble material is determiaed by weighing the ignited residue after extraction of the soluble material with sodium hydroxide. The sodium oxide content is determiaed ia a flame photometer by comparison to proper standards. Carbon dioxide is usually determiaed by the amount evolved, as ia the Underwood method. 

The air bag industry has become one of the principal users of pyrotechnic compositions in the world. Most of the current air bag systems are based on the thermal decomposition of sodium azide, NaN, to rapidly generate a large volume of nitrogen gas, N2. Air bag systems must function immediately (within 50 ms) upon impact, and must quickly deploy a pulse of reasonably cool, nontoxic, unreactive gas to inflate the protective cushion for the driver or passenger. These formulations incorporate an oxidizer such as iron oxide to convert the atomic sodium that initially forms into sodium oxide, Na20. Equation 1 represents the reaction. 

At room temperature, Htde reaction occurs between carbon dioxide and sodium, but burning sodium reacts vigorously. Under controUed conditions, sodium formate or oxalate may be obtained (8,16). On impact, sodium is reported to react explosively with soHd carbon dioxide. In addition to the carbide-forrning reaction, carbon monoxide reacts with sodium at 250—340°C to yield sodium carbonyl, (NaCO) (39,40). Above 1100°C, the temperature of the DeviHe process, carbon monoxide and sodium do not react. Sodium reacts with nitrous oxide to form sodium oxide and bums in nitric oxide to form a mixture of nitrite and hyponitrite. At low temperature, Hquid nitrogen pentoxide reacts with sodium to produce nitrogen dioxide and sodium nitrate. 

Techniques for handling sodium in commercial-scale appHcations have improved (5,23,98,101,102). Contamination by sodium oxide is kept at a minimum by completely welded constmction and inert gas-pressured transfers. Residual oxide is removed by cold traps or micrometallic filters. Special mechanical pumps or leak-free electromagnetic pumps and meters work well with clean Hquid sodium. Corrosion of stainless or carbon steel equipment is minimi2ed by keeping the oxide content low. The 8-h TWA PEL and ceiling TLV for sodium or sodium oxide or hydroxide smoke exposure is 2 mg/m. There is no defined AID for pure sodium, as even the smallest quantity ingested could potentially cause fatal injury. 

Additionally, it is a source of sodium oxide and a fluidizing agent. The amount of sodium nitrate added in the glass manufacture process is up to 2 wt % of the total raw material. 

Chemical Properties. Anhydrous sodium sulfite is stable in dry air at ambient temperatures or at 100°C, but in moist air it undergoes rapid oxidation to sodium sulfate [7757-82-6]. On heating to 600°C, sodium sulfite disproportionates to sodium sulfate and sodium sulfide [1313-82-2]. Above 900°C, the decomposition products are sodium oxide and sulfur dioxide. At 600°C, it forms sodium sulfide upon reduction with carbon (332). 

No reaction takes place below 500°C when sodium cyanide and sodium hydroxide are heated in the absence of water and oxygen. Above 500°C, sodium carbonate, sodium cyanamide [19981-17-0] sodium oxide, and hydrogen are produced. In the presence of small amounts of water at 500°C decomposition occurs with the formation of ammonia and sodium formate, and the latter is converted into sodium carbonate and hydrogen by the caustic soda. In the presence of excess oxygen, sodium carbonate, nitrogen, and water are produced (53). 

Natron, n. soda, in the following senses (1) sodium carbonate, Na2COa ( kohlensaurea Natron ) (2) sodium hydrogen carbonate, NaHCOa ( doppcltkohlensaures Natron ) (3) sodium hydroxide or caustic soda, NaOH, usually called Atznatron (4) in older names, sodium oxide, NajO (as in schwefel-saures Natron, sodium sulfate), -aiaun,... 

Fiber glass provides effective inhibition of polyethylene thermal destruction up to 400°C. The inhibitive efficiency increases with increased content of sodium oxide from 0.7-16% (Table 5). 

Figure 3-7. Effects of soda on motor and research octanes motor octane vs. sodium oxide [11] research octane vs. sodium oxide [4].

The equilibrium levels of the reaction products are very small, but both can dissolve in liquid sodium, and sodium oxide can form compounds with silica. As a consequence, the reaction moves to the right, leading to further reduction of silica. Nevertheless, vitreous silica crucibles have been used sucessfully for containing molten antimony (850°C), copper (1 210°C), gallium (1 100°C), germanium (1 100°C), lead (500°C) and tin (900 C). 

The continuous sintering is mainly a zone sintering process in which the electrolyte tube is passed rapidly through the hot zone at about 1700 °C. This hot zone is small (about 60 mm) in zone sintering, no encapsulation devices are employed. The sodium oxide vapor pressure in the furnace is apparently controlled by the tubes themselves. Due to the short residence time in the hot zone, the problem of soda loss on evaporation can be circumvented. A detailed description of / "-alumina sintering is given by Duncan et al. [22]. 

Sodium Oxide (Sodium Monoxide). Na20, mw 61.98, white-grey deliq powd, mp 1275° (subl), d 2.27 g/cc. Combines violently with w, forming NaOH. Sol in w and ethanol with decompn. 

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