| 单词 | chromate |
| 例句 | These are then taken up by the yellow pigment – lead chromate – turning it green. Yellow mellowed 2011-02-14T19:00:00Z At home, he was feeding his family turmeric polished with lead chromate and immediately stopped once he learned the health effects. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z When the researchers conducted a sampling spree again in 2021, they found that the use of lead chromate had practically disappeared. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z The researchers warned them that consuming lead chromate could lead to kidney and brain damage or cause developmental delays in children. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z In Bangladesh, even those who have committed a crime see this crackdown on lead chromate use as a net good. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z For most of his turmeric trading career, Sheikh engaged in an open secret: While processing raw turmeric to powder, he added a chemical called lead chromate to get the tubers to glow yellow. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z Cases of lung cancer may be from exposure to particles containing lead chromate and to asbestos in the paint trade. The 116 things that can give you cancer – the full list 2015-10-28T04:00:00Z In this sense, Bangladesh's success is noteworthy, said Roberts, who was not involved in the project to eliminate lead chromate from turmeric. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z Although he didn't know the precise health impacts of the lead chromate, he said, "it's common sense that chemicals are harmful." The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z It's in this step that lead chromate would be used to enhance color. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z Lead chromate is a chemical used in paints to, for instance, make school buses yellow, and it can enhance the radiance of turmeric roots, making them more attractive to buyers. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z The chromium in lead chromate poses a health risk, too. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z Lead chromate is comprised of two heavy metals, lead and chromium. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z The crackdown on turmeric in 2019 may, in part, explain why the use of lead chromate in polishing turmeric has since decreased. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z Only about 5 percent of 157 samples were found to be adulterated with lead chromate, down from nearly 50 percent before. The vice of spice: confronting lead-tainted turmeric 2023-08-02T04:00:00Z That sludge was believed to be lead chromate, a suspected human carcinogen. Indiana’s worst environmental disaster, 20 years later 2019-12-28T05:00:00Z Some spice processors in Bangladesh use an industrial lead chromate pigment to amp up turmeric’s bright yellow color, which makes it a prized addition to curries and other dishes. Some turmeric, wellness potion of the moment, may owe its yellow color to lead contamination, a study says 2019-09-28T04:00:00Z Department of Veterans Affairs has acknowledged they were exposed to sodium chromate. Taxpayers responsible for $30 million in legal fees 2015-09-02T04:00:00Z The mineral consisted of lead oxide and lead chromate, and the colour it produced became known to artists as "chrome red". The element that made the 20th Century shine - BBC News 2015-05-22T04:00:00Z Cobalt, and the preparations made from chromates, are the most resisting, and, when well prepared, the glaze in melting over them will bring out the colour with increased beauty. British Manufacturing Industries Pottery, Glass and Silicates, Furniture and Woodwork. 2012-02-26T03:00:18.883Z It is sometimes used as a paint, being identical in composition with the artificial product chrome-yellow; it is the only chromate of any importance found in nature. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z By means of the chromate of gelatin photographic process, such transfers may be made without great difficulty. Scientific American, Vol. XXXVII.?No. 2. [New Series.], July 14, 1877 A Weekly Journal Of Practical Information, Art, Science, Mechanics, Chemistry, And Manufactures 2012-01-05T03:00:29.743Z The following substances must be also excluded: Chrome yellow and other chromates, ultramarine, browns containing bituminous or other organic matter, compounds of lead and arsenic. Library Bookbinding 2011-12-24T03:07:58.950Z Strip out the lead oxide altogether, and you were left with the brilliant yellow of pure lead chromate. The element that made the 20th Century shine - BBC News 2015-05-22T04:00:00Z The chromate of iron, a mineral coming in large quantities from South America, is the base of all browns. British Manufacturing Industries Pottery, Glass and Silicates, Furniture and Woodwork. 2012-02-26T03:00:18.883Z By boiling white lead with chromate of soda and subsequently treating with small quantities of sulphuric acid, American vermilion, or basic lead chromate, is prepared. Paint Technology and Tests 2011-09-15T02:00:12.263Z A few chlorates, perchlorates, permanganates and chromates almost complete the list. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 1 "Evangelical Church Conference" to "Fairbairn, Sir William" 2011-07-16T02:00:16.387Z For fighters in the east, “the primary source is illicit activities, smuggling marble, chromate, gems and timber, as well as kidnapping,” the official said. News Analysis: Bin Laden?s Death and the New Unknown in Afghanistan 2011-05-07T23:57:07Z Epsom salts crystallizes in the orthorhombic system, being isomorphous with the corresponding zinc and nickel sulphates, and also with magnesium chromate. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 6 "English Language" to "Epsom Salts" 2011-02-19T03:00:59.807Z The colour is changed to a rich orange by a short, rapid passage through boiling milk of lime, and at once washing with water, a basic chromate of lead being thus produced. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" 2010-12-26T03:00:17.840Z The neutral chromate of lead, made from either the nitrate or acetate of lead and chromate of soda, finds wide use as a tinting pigment. Paint Technology and Tests 2011-09-15T02:00:12.263Z Chromium trioxide dissolves readily in water, and the solution is supposed to contain chromic acid, H2CrO4; the salts of this acid are known as the chromates. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Yellow.—Yellow ochre, gamboge, and chromate of lead. Paper and Printing Recipes A Handy Volume of Practical Recipes, Concerning the Every-Day Business of Stationers, Printers, Binders, and the Kindred Trades For this purpose Lord Rayleigh recommends a mixture of solutions of blue litmus and yellow potassium chromate. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 6 "Cockaigne" to "Columbus, Christopher" Normal chromates on the addition of silver nitrate give a red precipitate of silver chromate, easily soluble in ammonia, and with barium chloride a yellow precipitate of barium chromate, insoluble in acetic acid. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" Like the rest of the chromate pigments, it is a very slow-drying material, often requiring over a week to set up, unless considerable drier is added. Paint Technology and Tests 2011-09-15T02:00:12.263Z Chromates.—The alkaline chromates are usually obtained by fusion of a chromium compound with an alkaline carbonate and an oxidizing agent, such for example as potassium nitrate or chlorate. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Lead chromate is sometimes used, and many other substances, such as platinum, manganese dioxide, &c., have been suggested. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" The litmus stops the yellow and orange light, while the potassium chromate stops the blue and violet. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 6 "Cockaigne" to "Columbus, Christopher" The yellow colour of normal chromates changes to red on the addition of an acid, but goes back again to yellow on making the solution alkaline. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" Unfortunately this zinc chromate was added to a formula containing a large percentage of lithopone, and the destruction of the lithopone to a great extent affected the value of this test. Paint Technology and Tests 2011-09-15T02:00:12.263Z The majority of the chromates are yellow in colour, and many of them are isomorphous with the corresponding sulphates. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Any lead chloride dissolves, and may be identified by the yellow precipitate formed with potassium chromate. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" Its supplies of the following are inadequate: antimony, asbestos, kaolin, chromate, corundum, garnet, manganese, emery, nitrates, potash, pumice, tungsten, vanadium, zirconium. The Geneva Protocol Reducing agents, such as sulphurous acid and sulphuretted hydrogen, convert the chromates into chromic salts. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" Although the color of this pigment is not very pleasing, it has proved itself to be the equal of zinc chromate in its protective value. Paint Technology and Tests 2011-09-15T02:00:12.263Z The alkaline chromates are soluble in water, those of most other metals being insoluble. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Another important ruling, concerning coffee buyers and sellers, prohibits the importation of green coffees coated with lead chromate, Prussian blue, and other substances, to give the beans a more stylish appearance than they have normally. All About Coffee A small quantity of chromate of potash, about one grain to three ounces of solution of iodide of iron, gives a little more force to the picture. Notes and Queries, Number 203, September 17, 1853 A Medium of Inter-communication for Literary Men, Artists, Antiquaries, Genealogists, etc. Once the chromate has thoroughly killed and relaxed them, say after an hour or two, the specimens can be fixed, preserved, or manipulated as required. Practical Taxidermy A manual of instruction to the amateur in collecting, preserving, and setting up natural history specimens of all kinds. To which is added a chapter upon the pictorial arrangement of museums. With additional instructions in modelling and artistic taxidermy. I have experimented most extensively in many ways with the chromates and bichromates, and have succeeded in various ways in getting very good results. Photographic Reproduction Processes Lead chromate, PbCrO4, occurs native as the mineral crocoisite, and may be obtained as an amorphous pale yellow solid by precipitating a soluble lead salt by an alkaline chromate. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Lead and zinc chromates, Prussian blue, ferric oxid, coal-tar colors, and other substances of a harmful nature, have been employed for this purpose, being made to adhere to the beans with adhesives. All About Coffee I photograph the story in a liquid with light-sensitive chromates. Pygmalion's Spectacles Chlorides are estimated by titrating the neutral solution with N/10 silver nitrate solution, potassium chromate being used as indicator. The Handbook of Soap Manufacture The precipitate—silver citrate and chromate—is then dissolved by adding 1 dram of ammonia .880, and after 35 drops of strong nitric acid has been added the solution is ready for use.” Photographic Reproduction Processes It is decomposed by the addition of caustic alkalis, forming silver oxide and an alkaline chromate. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z The yellow and orange chromates of lead, for instance, withstanding as they do the action of the sunbeam, become by time, foul air, and the influence of other pigments, inferior to the ochres. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists Since the chromate changes into a dichromate in the presence of an acid, it will be sufficient to study the action of the dichromates alone. An Elementary Study of Chemistry A man may be the greatest proficient in the knowledge of the principles of chemical science, and yet be utterly ignorant of how bleaching powder, chromate of potash, or soda are made. Western Worthies A Gallery of Biographical and Critical Sketches of West of Scotland Celebrities Take of insoluble acid chromate of lime one part, and of gelatin five parts; but you do not say what further is to be done. Scientific American, Volume XXXVI., No. 8, February 24, 1877 A Weekly Journal of Practical Information, Art, Science, Mechanics, Chemistry, and Manufactures. After the calcium sulphate has settled, the potassium chromate solution is converted into bichromate by the action of sulphuric acid, and the salt is allowed to crystallize. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z But as no beauty of colour compensates for want of durability, their place should be supplied by lemon yellow proper, or chromate of baryta. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists The reason why the potassium salt rather than the sodium compound is used is that sodium chromate and dichromate are so soluble that it is hard to prepare them pure. An Elementary Study of Chemistry The excess found in the 50 c.c. must, of course, be multiplied by five, and then be deducted from the quantity of chromate originally run into the assay solution. A Text-book of Assaying: For the Use of Those Connected with Mines. Her hair is a crown, I can truthfully state 'Tis a metre long, nor curly nor straight, And it is as yellow as plumbic chromate In a slightly acid solution. Modern Eloquence: Vol III, After-Dinner Speeches P-Z Sodium bichromate, Na2Cr2O7�2H2O, may be obtained by the addition of the requisite quantity of chromium trioxide to a solution of sodium chromate. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Is a cheap inferior chrome yellow, unfit for artistic purposes, and consists of twenty-five parts of chromate of lead, fifteen of sulphate of lead, and sixty of sulphate of lime. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists When a chromium compound is fused with an alkali and an oxidizing agent a chromate is produced. An Elementary Study of Chemistry The determination is rendered sharper and less liable to error by the addition of a few drops of acetic acid to convert the chromate into bichromate. A Text-book of Assaying: For the Use of Those Connected with Mines. Very often in sending for bichromate of potash a mistake is made, and chromate of potash is procured instead; this is of a yellow colour, and will not answer the purpose. French Polishing and Enamelling A Practical Work of Instruction The chromates are stable towards heat; they are poisonous, and may be recognized by the yellow precipitates they give with soluble barium and lead salts. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Is chromate of zinc, a bright pale lemon-like yellow, slightly soluble in water. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists Most of the chromates are insoluble and can therefore be prepared by precipitation. An Elementary Study of Chemistry An excess of the chromate is required to complete the reaction, so that the point at which an indicator shows the presence of undecomposed chromate cannot be satisfactorily taken as the finish. A Text-book of Assaying: For the Use of Those Connected with Mines. A more per13manent colour results from nitric acid, and last of all by the successive introduction of acetate of lead and chromate of potash. French Polishing and Enamelling A Practical Work of Instruction Potassium chromate, K2CrO4, may be prepared by neutralizing a solution of potassium bichromate with potassium carbonate or with caustic potash. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Or chromate of bismuth, may be obtained either as a lemon or an orange yellow, sparingly soluble in water. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists When a dilute solution of a chromate or dichromate is acidified with an acid, such as sulphuric acid, no reaction apparently takes place. An Elementary Study of Chemistry Therefore an excess of the standard chromate must be run in, and such excess determined. A Text-book of Assaying: For the Use of Those Connected with Mines. The extract of walnut-shells and chromate of potash are procurable at any large druggist's establishment. French Polishing and Enamelling A Practical Work of Instruction Silver chromate, Ag2CrO4 is a dark red amorphous powder obtained when silver nitrate is precipitated by an alkaline chromate. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Or chromate of copper-potassa, is of a bright yellow tint, not insoluble in water. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists Their salts, the chromates and dichromates, are important compounds. An Elementary Study of Chemistry The same chromate solution must be used in this determination as was used in the precipitation. A Text-book of Assaying: For the Use of Those Connected with Mines. Having had occasion to prepare a quantity of sulphurous anhydride, for the purpose of reducing chromates previous to their analysis, I made use of the following apparatus, as represented in the accompanying figure. Scientific American Supplement, No. 633, February 18, 1888 They are readily decomposed by heat, leaving a residue of the normal chromate and chromium sesquioxide, and liberating oxygen; ammonium bichromate, however, is completely decomposed 913 into chromium sesquioxide, water and nitrogen. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z Under this name chromate of cadmium was introduced some few years back. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists The chromates of lead and barium separate as yellow precipitates. An Elementary Study of Chemistry In standardising the chromate solution, the standard lead nitrate solution is used. A Text-book of Assaying: For the Use of Those Connected with Mines. Yellow Pigments.—Cadmium sulphide, lead chromate and orpiment. Handbook on Japanning: 2nd Edition For Ironware, Tinware, Wood, Etc. With Sections on Tinplating and Galvanizing On platinum foil with nitre and carbonate of soda affords a yellow mass of chromate of potassa. A System of Instruction in the Practical Use of the Blowpipe Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations Like citron yellow and other chromates apt to assume a green cast, it should only be employed, if at all, when compounded for foliage tints, &c. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists It is then diluted with water to 500 c.c., and an aliquot part titrated with N/10 silver nitrate solution, using potassium chromate as indicator; 240 parts of bromine correspond to 58 parts of acetone. Nitro-Explosives: A Practical Treatise Add 20 grams of sodium acetate, warm, and precipitate the lead with a dilute solution of potassium chromate. A Text-book of Assaying: For the Use of Those Connected with Mines. It can be concentrated and used in preparing a new charge, the small quantity of calcium chromate present being an assistance, or: 2. Scientific American Supplement, No. 829, November 21, 1891 The colors used for this style of painting are zinc white, green oxide of chrome, cobalt green, chromate of lead, colcothar, ochers, and ultramarine. Scientific American Supplement, No. 483, April 4, 1885 Also called Scarlet Chrome, is a bright chromate of lead of an orange-red colour, the red being predominant. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists The wool is first boiled for 1� hours with chromate of potash and tartar, then dyed upon a fresh bath by 2� to 3 hours' boiling. Scientific American Supplement, No. 530, February 27, 1886 Some of the insoluble chromates are used as pigments; chromate of lead or chrome-yellow is the most important. A Text-book of Assaying: For the Use of Those Connected with Mines. The mass after lixiviation, being treated with a solution of sulphate or carbonate of potash or soda, will yield chromate of potash or soda, and by the employment of sulphuric acid, the corresponding bichromates. Scientific American Supplement, No. 829, November 21, 1891 This rock is highly charged with what appears to be chromate of iron. Personal Memoirs of a Residence of Thirty Years with the Indian Tribes on the American Frontiers It is, however, much more readily oxidized than sulphate of lead; and hence the thallium chromates would doubtless soon regain their former hue on exposure to a strong light. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists We add some special recipes for the various colors, the mordant for all of them being of 3 per cent. chromate of potash and 2� per cent. tartar for 100 by weight of dry wool. Scientific American Supplement, No. 530, February 27, 1886 The vanadates, like the chromates, are coloured compounds, generally yellow or red. A Text-book of Assaying: For the Use of Those Connected with Mines. If, instead of chromate or bichromate of potash or soda, chromic acid is sought, the mass after lixiviation is treated with sulphuric acid, and the chromic acid is obtained directly without any intermediate steps. Scientific American Supplement, No. 829, November 21, 1891 Its chief commercial importance is for its compounds, as potassium chromate, lead chromate, etc., which are brilliantly colored and are used dyeing and calico printing. The Gutenberg Webster's Unabridged Dictionary Section C Or; to a solution of Prussian blue in oxalic acid, first chromate of potash is added, and then acetate of lead. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists Several other of the chromates may be used in this process, but none is so successful as the chromate of copper. History and Practice of the Art of Photography Steel containing about 0.5 per cent. of it is rendered very hard; but its chief value is in its salts, the chromates. A Text-book of Assaying: For the Use of Those Connected with Mines. It is then titrated with decinormal silver nitrate till a drop of the solution is turned brown with neutral chromate. Scientific American Supplement, No. 324, March 18, 1882 The paper is now placed beneath the drawing in a copying-frame, and exposed for several minutes to the light; it is afterward laid in cold water in order to remove all excess of chromate. Scientific American Supplement, No. 286, June 25, 1881 Chromate of baryta, or chromate of bismuth is then formed, neither of which acts on the Prussian blue. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists The specks we found were mica; but I believe I am right in saying that there are large quantities of chromate of iron in the ranges that descend upon the river. A First Year in Canterbury Settlement The chromates in solution are more stable than other similar oxidising agents, and consequently are generally used in the laboratory as one of the standard oxidising agents for volumetric analysis. A Text-book of Assaying: For the Use of Those Connected with Mines. The methods of reducing with iron and titrating this with chromate of potassa, etc., have given a constant average of from 98.60-99.01. Scientific American Supplement, No. 324, March 18, 1882 Another black ink not durable, however, is "logwood;" its extract is combined with a little chromate of potassium and boiled together in water. Forty Centuries of Ink or, a chronological narrative concerning ink and its backgrounds, introducing incidental observations and deductions, parallels of time and color phenomena, bibliography, chemistry, poetical effusions, citations, anecdotes and curiosa together with some evidence respecting the evanescent character of most inks of to-day and an epitome of chemico-legal ink. We have found in them a large proportion of orpiment, chromate of lead, &c., together with quantities of soluble salt, extracted by boiling water. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists It is a mixture more durable and more transparent than chrome greens made with chromate of lead. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists On boiling an insoluble chromium compound with chlorate of potash and nitric acid, the chromium passes into solution as chromate. A Text-book of Assaying: For the Use of Those Connected with Mines. Another Mineral Green adopted in Germany as a substitute for the poisonous Schweinfurt green, is composed of chromate of lead, carbonate of copper, oxide of iron, and chalk. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists To the solution one thousandth of its weight of yellow chromate of potash is to be added gradually. Forty Centuries of Ink or, a chronological narrative concerning ink and its backgrounds, introducing incidental observations and deductions, parallels of time and color phenomena, bibliography, chemistry, poetical effusions, citations, anecdotes and curiosa together with some evidence respecting the evanescent character of most inks of to-day and an epitome of chemico-legal ink. The chromates are often mixed with sulphate of lead, as well as with the sulphates of baryta and lime. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists By heating chromate of stannic oxide to bright redness, a dark violet mass is obtained, which is better adapted to enamel painting than to the palette. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists The aqueous extract containing the chromate is ready for volumetric work, except in those cases where nitre has been used. A Text-book of Assaying: For the Use of Those Connected with Mines. This is based on the oxidation of ferrous iron by the solution containing the chromium as chromate. A Text-book of Assaying: For the Use of Those Connected with Mines. Colored paper material with indigo and with a subsequent treatment of chromates soluble only in alcohol. Forty Centuries of Ink or, a chronological narrative concerning ink and its backgrounds, introducing incidental observations and deductions, parallels of time and color phenomena, bibliography, chemistry, poetical effusions, citations, anecdotes and curiosa together with some evidence respecting the evanescent character of most inks of to-day and an epitome of chemico-legal ink. Or chromate of baryta, is exceedingly difficult to make well. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists Small quantities of chromate in neutral solution can be found by the dark or violet-red colouration imparted thereto on boiling with a dilute decoction of logwood. A Text-book of Assaying: For the Use of Those Connected with Mines. The iron thus found is deducted from that taken, and the difference gives the iron oxidised by the chromate. A Text-book of Assaying: For the Use of Those Connected with Mines. The addition of potassium chromate to the acetate solution reprecipitates the lead as a yellow chromate. A Text-book of Assaying: For the Use of Those Connected with Mines. It is best contained in a pint flask, and the standard chromate solution used with an ordinary burette. A Text-book of Assaying: For the Use of Those Connected with Mines. We have occasionally found Mars yellow mixed with orpiment, or chromate of lead, for the purpose of brightening the colour. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists Run in the chromate solution in a steady stream until the whole of the lead has been precipitated. A Text-book of Assaying: For the Use of Those Connected with Mines. The solution containing the chromate is added, and the remaining ferrous iron titrated with the permanganate or bichromate of potassium solution, as described under Iron. A Text-book of Assaying: For the Use of Those Connected with Mines. The rest in a form soluble in water, as potassium or sodium chromate. A Text-book of Assaying: For the Use of Those Connected with Mines. If any chromate is present reduce it with sodium sulphite or sulphuretted hydrogen. A Text-book of Assaying: For the Use of Those Connected with Mines. Or chromate of lime, is a pale whitish yellow, poor in colour, partly soluble, and not at all to be depended on. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists Small quantities of chromium may be determined, after conversion into chromate, colorimetrically. A Text-book of Assaying: For the Use of Those Connected with Mines. The soluble chromates, those of soda and potash, are valuable chemicals, and are largely used in the preparation of pigments, dyeing and tanning, and as oxidising agents. A Text-book of Assaying: For the Use of Those Connected with Mines. The solution is allowed to settle, and the clear liquid decanted into a stoppered bottle labelled "chromate indicator for chlorine." A Text-book of Assaying: For the Use of Those Connected with Mines. Add a few drops of the chromate indicator and continue the addition of the silver nitrate until the yellow colour of the solution becomes permanently tinted red, after shaking. A Text-book of Assaying: For the Use of Those Connected with Mines. Like all the chromates of lead, it is characterized by power and brilliancy; but also by a rankness of tone, a want of permanence, and a tendency to injure organic pigments. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists Chlorine.—Weigh up two separate lots of 1 gram each; dissolve in 100 c.c. of water, and determine the chlorine by titrating with the standard silver nitrate solution, using chromate of potash as indicator. A Text-book of Assaying: For the Use of Those Connected with Mines. Chromic salts are oxidised to chromate by fusion with "fusion mixture" and nitre, or by treating with chlorine in an alkaline solution. A Text-book of Assaying: For the Use of Those Connected with Mines. Silver chromate is decomposed and consequently decolorised by solution of any chloride. A Text-book of Assaying: For the Use of Those Connected with Mines. This shows that the chlorine is all precipitated, and that the chromate is beginning to come down. A Text-book of Assaying: For the Use of Those Connected with Mines. On chromate of cadmium, made with bichromate of potash, thallium would naturally confer an orange hue. Field's Chromatography or Treatise on Colours and Pigments as Used by Artists Boil the solution, allow to settle for a minute or so, filter off 50 c.c., and determine the excess of chromate colorimetrically. A Text-book of Assaying: For the Use of Those Connected with Mines. |
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