Porcelain crucibles

Sodium Fusion on Semi mlcro Scale. The Lassaigne test can be readily carried out with as little as 0 01 g. of material, using sodium pellets about 2 mm. in diameter in a tube about 3 x. After fusion, the red-hot tube is plunged into distilled water in a small porcelain crucible or in a boiling tube. The mixture is then heated, filtered and tested as already described. 

Place about 01 g. of the compound in a porcelain crucible or crucible cover. Heat it gently at first and finally to dull redness. Observe ... 

Carbon and Hydrogen.—Carbon compounds are frequently inflammable, and when heated on platinum foil take fipe or char and burn away. A safer test is to heat the substance with some easily reducible metallic oxide, the oxygen of which forms carbon diovide with the carbon present. Take a piece of soft glass tube about 13 cm. (5 in.) long, and fuse it together at one end. Heat a gram or two of fine copper oxide in a porcelain crucible for a few minutes to drive off the moisture, and let it cool in a desiccator. Mix it with about one-tenth of its bulk of powdered sugar in a mortar. Pour the mixture into the tube, the open end of which is now drawn out into a wide capillary and oeni. at the same time into the form Fig. i. 

Commercial selenium dioxide gives more consistent results when freshly sublimed material is used. Place the oxide (50 g) in a 7-cm porcelain crucible upon which is set a 250-ml filter flask cooled by running through it a stream of water. The crucible is heated with a low flame until sublimation is complete (20-30 minutes). After cooling, the sublimed selenium dioxide is scraped from the flask and is stored in a stoppered bottle. 

Porcelain crucibles are very frequently utilised for igniting precipitates and heating small quantities of solids because of their cheapness and their ability to withstand high temperatures without appreciable change. Some reactions, such as fusion with sodium carbonate or other alkaline substances, and also evaporations with hydrofluoric acid, cannot be carried out in porcelain crucibles owing to the resultant chemical attack. A slight attack of the porcelain also takes place with pyrosulphate fusions. 

HDPE/Ti02 Residual ash Porcelain crucibles or quartz fibre cmcibles 15 min at 800 °C [87]... 

Mayes, R. B. et al., School Set. Rev., 1975, 56(197), 819-820 When the residue from combustion of magnesium in air was removed from the porcelain crucible, a grey stain remained. Addition of cold cone, nitric acid to remove the stain led to a violent reaction. This was found to be caused by the presence of magnesium silicide in the stain. 

Test 4. To 30 mg of miconazole in a porcelain crucible add 0.3 g of anhydrous sodium carbonate R. Heat over an open flame for 10 min. Allow to cool. Take up the residue with 5 mL of dilute nitric acid R and filter. To 1 mL of the filtrate add 1 mL of water R. The solution gives reaction (a) of chloride (general test (2.3.1)). 

Samples are oven dried at 100°C after which they are weighed in order to measure water content. TC and TS are measured by introducing dried samples to the Carbon Sulfur (CS) automatic analyzer (Eltra CS-800) instrument. Subsequently, 2g of each sample is introduced in preweighed high temperature porcelain crucibles and is introduced to a high temperature muffle furnace for the removal of carbonates at 900C. Samples are then introduced to the CS automatic analyzer for measurement of organic residual carbon. 

The normality of the stronger solution is checked once a month in the following way 0.1 ml ethyl hydroperoxide solution +2 ml potassium iodide (20 g/100 ml) + 2 chops of glacial acetic add are placed in a porcelain crucible, covered with a lid, and allowed to stand at room temperature for 4 hours. The amount of iodine released is then titrated with 0.05 N sodium thiosulfate. 

A spirit burner. .., blow-pipe, one platinum crucible, one platinum sheet and 3-4 platinum wires, a test tube stand with 10-12 test tubes, several beakers and flasks, one porcelain dish and a pair of porcelain crucibles, several glass filter funnels in various sizes, a wash-bottle, several rods and watch glasses, one agate mortar, several iron spoons, a pair of steel or brass pincers, a filtration stand made of wood and one iron tripod stand. 

Dry sediment (0.15-0.2g) was ignited in a muffle furnace in a porcelain crucible (550°C for lh). After cooling, the residue was washed into a 100ml Erlenmeyer flask with 25ml mol L-1 hydrochloric acid and boiled for 15min on a hot plate. The sample was diluted to 100ml and orthophosphate was determined as in the perchloric acid method. Standards and blanks were not ignited. 

To disintegrate the filter paper, the rinsed filter paper containing the precipitate is folded and placed into a preweighed porcelain crucible and the crucible is heated, first cautiously with a cooler Bunsen burner flame, so as to dry and char the filter paper, and then with the full heat of a Meker burner. For this final ignition step, the crucible should be tilted to one side and partially covered with the crucible lid so that the burner flame can be directed to the bottom of the crucible, thus avoiding engulfing the... 

Prepare a porcelain crucible and lid by cleaning with hot soapy water and a brush, followed by rinsing and drying with a towel. Then heat the crucible, with lid slightly ajar, in a muffle furnace set at 950°C for 30 min. This step is to ensure that any volatile material will be removed now rather than later, when the weight loss is critical Allow to cool for 10 min on a heat resistant surface and then 10 min more in a desiccator. Then weigh the crucible with lid on an analytical balance. 

Obtain a sample from your instructor. Record the unknown number and dry as discussed in Experiment 6 and in Section 3.7. Also, obtain and prepare two porcelain crucibles and lids, as done... 

Transfer approx 5g of the specimen, weighed to the nearest mg, to a fared porcelain crucible and ignite for 4 Hrs in a muffle furnace maintained at 900-25°C, cool in a desiccator and weigh to the nearest mg... 

Determination of Asb. Transfer (to a tared, porcelain crucible for Grade I III, and platinum crucible for Grade II IV) a portion of approx one g of the sample and weigh accurately. Using a gas flame or muffle furnace, ignite the crucible and contents until... 

Method 3. Place an amount of the sample, directed in the monograph, in a quartz or porcelain crucible, heat continuously, gently at first, and then increase the heat until incineration is completed. After cooling, add 1 mL of aqua regia, evaporate to dryness on a water bath, moisten the residue with 3 drops of hydrochloric acid, add 10 mL of hot water, and warm for 2 minutes. Add 1 drop of phenolphthalein TS, add ammonia TS dropwise until the solution develops a pale red color, add 2 mL of dilute acetic acid, filter if necessary, wash with 10 mL of water, transfer the filtrate and washing to a Nessler tube, and add water to make 50 mL. Designate it as the test solution. 

Put several iron II) sulphate crystals on the lid of a porcelain crucible, heat them, and then strongly roast them. Hold litmus paper wetted with water over the crystals. What happens Write the equation of the reaction. 

Prepare platinized asbestos as follows put 5 g of purified asbestos into a bowl and pour a 1-2% cbloroplatinic acid solution over it. Transfer the fibres impregnated with the solution into a porcelain crucible and roast them first carefully, and then strongly on a blowtorch. Store the prepared catalyst in a jar with a ground-glass stopper. Roast the platinized asbestos -without fall before each experiment. 

Preparation of Sodium Carbonate. Put about 0.5 g of sodium bicarbonate onto the bottom of a porcelain crucible and roast it on a gas burner during 20-30 min. 

Processing of Barium Sulphate into Barium Chloride, a. Preparation of Barium Sulphide. Mix 4 g of barium sulphate and 2 g of powdered charcoal, place the mixture into a chamotte or porcelain crucible, and cover the mixture with powdered charcoal. Close the crucible with its lid and roast it strongly (600-700 °C) for an hour in a muffle furnace. Write the equation of the reaction. 

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