Fused sodium-potassium nitrate

The acid-base properties of fused alkali nitrates were first noted when dichromate was added to fused sodium-potassium nitrate eutectic (/)/. Gaseous nitrogen dioxide and oxygen were slowly given off with the conversion of the dichromate to chromate. It was postulated that N02+ was formed as intermediate ... 

Kust (4) has potentiometrically determined the equilibrium constant for carbonate dissociation in fused sodium-potassium nitrate eutectic ... 

A manganate is produced when a manganese compound is fused with potassium nitrate and sodium carbonate (see Section III.28, Dry tests). 

Black Powder. Black powder is mainly used as an igniter for nitrocellulose gun propellant, and to some extent in safety blasting fuse, delay fuses, and in firecrackers. Potassium nitrate black powder (74 wt %, 15.6 wt % carbon, 10.4 wt % sulfur) is used for military appHcations. The slower-burning, less cosdy, and more hygroscopic sodium nitrate black powder (71.0 wt %, 16.5 wt % carbon, 12.5 wt % sulfur) is used industrially. The reaction products of black powder are complex (Table 12) and change with the conditions of initia tion, confinement, and density. The reported thermochemical and performance characteristics vary greatly and depend on the source of material, its physical form, and the method of determination. Typical values are Hsted in Table 13. 

Organic selenium compounds and siUceous materials (rock, ore, concentrates) are fused with mixtures of sodium carbonate and various oxidants, eg, sodium peroxide, potassium nitrate, or potassium persulfate. For volatile compounds, this fusion is performed in a bomb or a closed system microwave digestion vessel. An oxidizing fusion usually converts selenium into Se(VI) rather than Se(IV). 

Substances which are insoluble or only partially soluble in acids are brought into solution by fusion with the appropriate reagent. The most commonly used fusion reagents, or fluxes as they are called, are anhydrous sodium carbonate, either alone or, less frequently, mixed with potassium nitrate or sodium peroxide potassium pyrosulphate, or sodium pyrosulphate sodium peroxide sodium hydroxide or potassium hydroxide. Anhydrous lithium metaborate has found favour as a flux, especially for materials containing silica 12 when the resulting fused mass is dissolved in dilute acids, no separation of silica takes place as it does when a sodium carbonate melt is similarly treated. Other advantages claimed for lithium metaborate are the following. 

The primary synthetic route proceeds via oxidative dimerization of 2-aminoan-thraquinone in the presence of an alkali hydroxide. 2-aminoanthraquinone, for instance, is fused with potassium hydroxide/sodium hydroxide at 220 to 225°C in the presence of sodium nitrate as an oxidant. New techniques involve air oxidation of 1-aminoanthraquinone at 210 to 220°C in a potassium phenolate/sodium acetate melt or in the presence of small amounts of dimethylsulfoxide. A certain amount of water which is formed during the reaction may be removed by distillation in order to improve both efficiency and yield. 

Tungsten metal is not affected by aqueous alkalies at room temperature. In molten state, caustic soda and caustic potash slowly oxidize tungsten in the presence of air. Oxidiation is more rapid in the presence of an oxidizing agent such as potassium nitrate, potassium chlorate, or lead dioxide. A similar reaction occurs with fused sodium or potassium carbonate. Tungsten dissolves... 

Ammonium nitrate is also miscible with fused salts of nitric acid. The composition of the eutectics and the fusion temperatures of mixtures with sodium, potassium, and calcium nitrate are considered in future chapters (Vol. III). Data concerning the properties of mixtures with guanidine nitrate, nitroguanidine, ethylene diamine dinitrate, are also reported in Vol. III. 

A fused salt bath consisting of 8.5 parts (by weight) of sodium nitrite and 10 parts of potassium nitrate has a melting point of about 140° and may replace the metal bath. 

About 2 grams of a mixture of sodium carbonate and potassium nitrate are melted in a porcelain crucible and about i gram of the substance, finely cut, gradually added to the fused mass. When cold, the mass is heated with water and the clear liquid decanted off, the residue being subsequently boiled with two separate quantities of 50 c.c. of water and filtered. The lead and zinc are left as carbonates and, after solution in acetic acid, may be identified in the usual way. The presence of zinc is also shown by the yellow colour of the hot, fused mass. 

For the detection of the principal mordants the following method may be employed About 10 grams of the fabric are incinerated in a platinum dish and the ash then fused with about five times its weight of dry sodium-potassium carbonate and a little potassium nitrate. 

Schneider 3 believed he had obtained the oxide, Pd5Os, by fusing the double palladium potassium sulphide with sodium hydroxide and potassium nitrate. It is very doubtful, however, if this is to be regarded as a separate chemical entity.3... 

Many catalysts used in chemical synthesis can be treated in the same way, often the nitrous oxide/acetylene flame is used because of the refractory nature of the elements to be determined. Harrington and Bramstedt [56] have determined rhenium in electro-chemical surface catalysts by stripping the coating with molten potassium hydroxide/ potassium nitrate. This melt was extracted with hydrochloric acid, the residue was fused with sodium peroxide for further rhenium determination. Titanium, being the substrate on which the catalyst was coated, was added to the standards, an air/acetylene flame and 343.3 nm were used for the finish. 

Sodium carbonate bead tests The sodium carbonate bead is prepared by fusing a small quantity of sodium carbonate on a platinum wire loop in the Bunsen flame a white, opaque head is produced. If this is moistened, dipped into a little potassium nitrate and then into a small quantity of a manganese compound, and the whole heated in the oxidizing flame, a green bead of sodium manganate is formed ... 

The presence of manganese and of chromium is confirmed by fusing the substance with sodium carbonate and potassium nitrate on platinum foil or... 

SYN POTASSIUM nitrate mixed (fused) with SODIUM NITRITE pop... 

POTASSIUM NITRATE mixed (fused) with SODIUM NITRITE pOT) see PLMOOO POTASSIUM NITRITE (1 1) see PLM500 POTASSIUM NITRITE pop see PLM500 POTASSIUM NITROTRICHLOROPLATINATE see PLN050... 

The applicability of the laws has been confirmed under extreme conditions for example, Richards and Stull (1902) found that a given quantity of electricity deposited the same weight of silver, within 0.005 per cent, from an aqueous solution of silver nitrate at 20° and from a solution of this salt in a fused mixture of sodium and potassium nitrates at 260°. The experimental results are quoted in Table II. 

Experiment 36. — Supplies Test tubes, thermometer, 5 gm. each of fused calcium chloride, potassium nitrate, ammonium nitrate, dehydrated copper sulphate, i gm. each of sodium hydroxide and potassium hydroxide, and a few cubic centimeters of concentrated sulphuric acid. 

Measure 10 cc. of water into a test tube, take the temperature, add at one time 5 gm. of fused calcium chloride. As it dissolves, stir with the thermometer and observe the highest reading. Record in the proper place in the table below. Repeat successively with separate portions of water and the ammonium nitrate, potassium nitrate, -dehydrated copper sulphate, potassium hydroxide, sodium hydroxide, and concentrated sulphuric acid (add the acid to the water). Tabulate the results as follows —... 

Black powder is mainly used as an igniter for nitrocellulose gun propellants and to some extent in safety blasting fiises, delay fuses, and firecrackers. Potassium nitrate black powder (74 wt percent plus 15.6 wt percent carbon, 10.4 wt percent sulfur) is used for military applications. The slower-burning, less costly, and more hygroscopic sodium nitrate... 

In fused sodium nitrate-potassium nitrate, decomposition of chlorate and bromate is thought to occur through acid-base reactions fundamentally similar to some which have been proposed for aqueous solutions . The acid used was dichromate and the processes appear to involve the net reaction... 

Powdered chromium is slowly attacked by mercuric chloride in solution, with the formation of chromic chloride. Though unattacked by fused sodium carbonate, fused potassium nitrate and chlorate oxidise it vigorously. Pyrophoric chromium (see p- 11) combines with nitrogen on heating. ... 

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