In atomic absorption photometry, a solution of the metal is vaporized and fed into a flame with the fuel, where the metal is converted to the atomic state. A lamp whose cathode contains the metal being analyzed sends a beam of light through the flame to the spectrophotometer, which measures how much of the light is absorbed and, therefore, the concentration of the particular metal. Because the lamp's cathode is made of the metal being analyzed, the wave lengths in the light beam are characteristic of that metal. Other metals in the test solution, then, rarely interfere in the analysis. Different analyses require different lamps. The lamp housing in the new Beckman accessory for example, has connections for three lamps—two in standby and one in use, with easy switching from one -to another. All is not rosy in atomic absorption, however. There are limitations. Some metals tend to form refractory compounds, rather than atoms, in the flame. If few atoms are present, the method fails. If many of the atoms of a metal are excited by the energy of the flame (as in flame photometry), the accuracy falls off. For these and other reasons the limits of detection vary from element to element. Zinc, which fails completely in emission photometry, is easily detected in the parts-per-million range with the absorption method. Vanadium cannot yet be measured because it forms oxides, rather than atoms. To meet the needs of this new technology, instrument makers try to make their units as versatile as possible. Beckman, for example, furnishes its accessory with either of two burners, which are interchangeable. The laminar-flow burner requires less sample and is more sensitive with a limited amount. It is applicable to 60 to 70% of the metals commonly analyzed. The turbulent-flow burner—actually three burners in a line—uses hydrogen, or, for a hotter flame, acetylene. A special feature makes it possible for the light beam to pass through the flame three times for greater sensitivity than with a single pass. P-E Expanding. Perkin-Elmer is expanding its line with the Model 290, a low-cost ($2900) instrument. At the same time, the company is beefing up the performance that can be achieved with its high-powered Model 303 by offering a digital con-
centration readout accessory for use with the unit. The Model 290 is intended for routine operation where a large number of samples are analyzed for the same one or two elements. Four samples per minute can be analyzed in such cases, P-E says. Readout gives concentration directly. The unit is designed to take P-E hollow-cathode lamps, including new multiple-element lamps for calcium-magnesium and for cobalt-chromium-copper-ironmanganese-nickel. In a five-day precision study, P-E says, the 290 showed an average deviation of only 1 to 2% of calcium and magnesium present in eight preserved urine specimens. In consecutive determinations, the company says, calcium and magnesium concentrations show standard deviations well below 1% of the amount present. The digital concentration readout accessory is designed to improve the sensitivity, precision, speed, and convenience of the Model 303. It automatically computes and displays the concentration of an element in a sample being analyzed. Priced at $2100, the accessory will be ready for delivery in April, as will the Model 290. The accessory can be set to take four, eight, or 16 independent readings of the same sample and present their average. Smoothing-time-constants up to 20 sec. can also be selected. Readout is four illuminated digits which present concentration directly in whatever units the accessory is calibrated for. Meanwhile, Jarrell-Ash is readying its new Model 82600, which will cost between $8000 and $9000. It will have a 0.75-meter focal length and will handle up to 12 channels. Each hollow-cathode lamp will normally be capable of analyzing for three elements, with lamps ordered to fit the range of elements of most interest. Aztec, which markets the Australian Techtron instrument, will introduce Techtron's second-generation AA4. The unit, which will sell for less than $3000, is designed for rapid analyses in clinical and control laboratory applications. Rounding out the new instruments is a unit from England's Hilger & Watts designed around the company's Uvispec H-700. The new instrument is an a.c. unit with in-line cathode tubes. Marketed in the U.S. by Engis Equipment, it will cost $4000 to $5000 and be available this summer.
Process May Reduce Pollution From Burning Coal Refuse Piles A process designed to reduce the air pollution from burning coal refuse piles is getting a tryout this month. A pilot plant to test the process has been built at Barnesboro, Pa. The process uses a heavy liquid to separate marketable high-ash coal from nonburnable waste rock. Nearly 500 mountains of coal refuse, waste material from coal cleaning operations, are burning uncontrollably in 15 states in the U.S., according to a Bureau of Mines survey. These refuse banks, some of which weigh as much as 20 million tons, ignite spontaneously and are nearly impossible to quench. Each year they pour thousands of tons of pollutants into the atmosphere. The new approach for eliminating air pollution from this source was begun at Pennsylvania State University in 1962 by H. Beecher Charmbury, Pennsylvania's secretary of mines. The work was taken over by James K. Kindig of the department of mineral preparation at Penn State (University Park, Pa.). The pilot plant is a semimobile, four-story, L-shaped structure. Coal refuse from bituminous regions will serve as the first feed. Anthracite coal refuse is slated for a later try. In the process, the unburned coal refuse is dumped into receiving hoppers and conveyed to a screening and crushing operation. Noncoal refuse, such as mine-shaft timbers, is removed by screening. The coal is crushed to pieces less than 1 in. in diameter, and powder-sized coal particles discarded. The crushed coal refuse is carried to a cyclone extractor by a heavy slurry of flour-fine magnetite. Float. The coal particles float in the heavy liquid while slate and stone sink. The high-speed action of the cyclone forces the slate, some of the magnetite, and the rock out the bottom of the cyclone extractor while coal is recovered at the top. Slate and rock are screened and washed to recover the magnetite. Separated coal is also washed to recover the magnetite and then spun dry. Both wash streams combine, and the magnetite recycles. About 50 tons of coal refuse can be processed in an hour, Mr. Kindig says. Four tons of raw material will yield about 1 ton of usable coal. The pilot plant will be used to develop the JAN.
25, 1965 C & E N
49
Drying tower Cool to 800°F. Converter Catalyst pellets
Absorption tower
Boiler Selective absorbant
Reheater (direct contact)
Standard 98% acid I Absorption tower
Air Pollution from H2S04 Production Is Target of Conversion Process Another SO-to-S0 3 conversion process designed to decrease the air pollution problems of sulfuric acid manufacturers has been developed, this one by Von Bree, Inc., of Newark, Del. Similar in principle but differing in technique from the Bayer double-contact process (C&EN, Dec. 2 1 , 1964, page 42) the Burkhardt S.A. (selective absorbant) process can be installed in both existing and new acid plants— before or following the absorption tower—to increase conversion efficiency. The conversion (99.0 to 99.6%) that can
process so as to make it economically attractive for coal producers to reprocess their own refuse banks. The most expensive material in the process is the magnetite, which currently costs about $40 per ton. Losses in the pilot plant could amount to 2 lb. per ton of recovered coal. These losses will, in part, help determine the price that must be obtained for the second-rate, high-ash coal product to make the process economical. The pilot plant was built with funds from the U.S. Public Health Service. It was built to Mr. Kindig's specifications by Heyl and Patterson, Inc., an engineering firm from Pittsburgh, Pa. The test plant is located near a commercial coal cleaning plant operated by Barnes and Tucker Coal Co., of Barnesboro. This company has aided the research project by supplying land, labor, and coal refuse for the pilot project. 50
C&EN
JAN.
2 5,
1965
be expected in plants using brimstone sulfur as raw material will result in lowering SO- concentration in plant exit gases to 0.05 to 0.10% by volume, Von Bree says. The converting unit uses two or three layers of catalyst pellets with cooling between each stage. The Burkhardt process uses direct contact heating instead of heat-exchanger units to reheat gases. This makes it possible to use unlined carbon steel. The process will be licensed either directly or through selected engineering contractors.
New Crystalline Compound Detected in Hydraulic Cements A new crystalline compound has been detected during a study of hydraulic cements at the Institute of Applied Technology, of the National Bureau of Standards. The compound is a gehlenite hydrate which forms at temperatures above 250° C. NBS says the material doesn't form in steamcured concrete made under present industry practice, but should be of interest in the hydrothermal treatment of cements and blast-furnace slags. X-ray diffraction patterns have shown that the compound has a bodycentered cubic structure with a unit cell edge of 0.883 nanometer. The index of refraction is 1.628. A formula based on the analyses indicates that there is a relation between the compound and mineral gehlenite. This relationship is of interest to the cement industry because gehlenite re-
acts with water under hydrothermal conditions to form a hydrogarnet. The ratio of calcium oxide to aluminum oxide in the hydrogarnet is 3 to 1 rather than 2 to 1 as in conventional steam-cured concrete.
Hair Used as Sr'Indicator The use of human hair as an indicator of the intake and body burdens ot strontium-90 is being investigated by the Public Health Service. Preliminary indications are that correlations may exist between strontium-90 levels in the human diet and strontium-90 levels in human hair. Under this continuing program, the strontium-90 levels in the hair of boys residing at 50 boarding schools will be measured. The ratio of strontium-90 to calcium in hair will be compared with the ratio in monthly samples of total diet.
BRIEFS Three standard hydrocarbon samples
have been added to the list of the American Petroleum Institute. The hydrocarbons, cis-cyclooctene, cyclooctane, and l,3-dimethyl-5-f^rf-butylbenzene, are available in 5-ml. ampoules at $90 per ampoule. Orders for samples should be addressed to Petroleum Research Laboratory, Carnegie Institute of Technology, Pittsburgh, Pa. 15213, Attention: Beveridge J. Mair.
HE
•• L t
specification and application J information
j
NEW! ULTRA LOW TEMPERATURE FACT FILE
A second glass viscosity standard is
available from the Standard Samples Clerk, National Bureau of Standards, Washington, D.C. 20234, for $60. NBS Standard Sample 711 is a homogeneous lead-silica glass for use in calibrating commercial glass viscometers. The viscosity-temperature relationship for this glass is approximately 100° C. lower (460° to 1300° C.) than Standard Sample 710 (575° to 1430° C ) .
A method for using metal from junked automobiles in treating nonmagnetic taconite, a type of iron ore now useless, is being developed at the Bureau of Mines' Metallurgy Research Center in Minneapolis, Minn. When scrap iron is mixed with nonmagnetic taconite and heated, the scrap absorbs oxygen from the ore. This causes the ore to change its molecular structure and become magnetic. The iron oxide can be removed by magnetic separation and sent to the blast furnace. A medium-sized plant using the process to make 5 million tons of taconite ore concentrate per year would use about 600,000 tons of scrap, Bureau of Mines estimates.
Featuring cabinets from 1!4—24 cu. ft. Pulldowns from ambient to —140 F.( 96C).
Revco c a b i n e t s are used t h e world over for i n d u s t r i a l , medical a n d scientific research projects. Send for t h i s FREE line a n d fact folder t o d a y . C h a n c e s are t h e r e ' s a Revco cabin e t j u s t r i g h t for your next j o b a p p l i c a t i o n ! INC. Industrial Products Division
x
ORGANIC INTERMEDIATES offered by Pfister Chemical Works in commercial quantities
Pfister 5-chloro salicylanilide White powder, 99% minimum purity, for use in mildewcides, fungicides, pharmaceuticals, and dye intermediates.
5-chloro-salicylic acid White crystals of 99% minimum purity for use in moth-proofing, insecticides, pharmaceuticals and dye intermediates.
Taylor Instrument Companies is now
offering its engineering services for development of direct digital control systems. The Rochester, N.Y., company has added personnel to its staff to implement an accelerated program leading to direct digital control development. Taylor doesn't plan to offer a digital computer of its own. Rather the firm will develop and design a control system based on an existing computer. The company will then offer its own line as software to instrument the entire direct digital control system.
Dept.2315
Deerfield, Michigan
Samples are available in the U. S. Specifications and price list of these and other intermediates available on request. Phone 201 - WH 5-5400 or write:
Pfister
CHEMICAL WORKS, INC Ridgefield, New Jersey JAN.
2 5, 196 5 C & E N
51
C&EN
INDUSTRlAL CHEMICAL SPECIALTIES
PROGRESS REPORT
These items have all been mentioned editorially in C&EN in the past month. If you haven't already sent for information on them, just check the appropriate key numbers on the coupon on page 56y and C&EN's Readers' Information Service will forward your request to the manufacturer. 1
Product
Monomers (Sipomer 2M1-M and HEM-1) Fabric finish (Bypel) Molding compounds (Canrad Glo) Polyurethane elastomer (Chem-o-thane) Cellulose reactant (Dextraset CRS) Coating Thermal stabilizer (Arsonone-S) Adhesive (Eccobond 85A) Copolymer emulsion (Resyn 76-8174) Complexing agents
C63 C64 C65 C66 C67 C68 C69 C70 C71
C72
Polyester resins C73 (Cyplex 1473-5, 1476-8, and 1526) Additive (BF-7)
C74
Company
Alcolac Chemical Corp. Baltimore, Md. Bryant Chemical Corp. North Quincy, Mass. Canrad Sales Corp. New York, N.Y. Chemical Products Corp. Warwick, R.I. Dexter Chemical Corp. New York, N.Y. Electro-Science Laboratories Philadelphia, Pa. El Monte Chemical Co. Alhambra, Calif. Emerson & Cuming, Inc. Canton, Mass. National Adhesives Division National Starch and Chemical Corp. New York, N.Y. Nopco Chemical Co. Newark, N.J. Plastics and Resins Division American Cyanamid Co. | Wallingford, Conn. U.S. Movidyn Corp. Chicago, III.
Features Dimethyl aminoethyl methacrylate and hydroxyethyl methacrylate A one-package, water-repellent finish for cotton fabric Phosphorescent polystyrene, polyethylene, and other plastics Cures without heat and has high resilience and compression For deferred-cure permanent-crease process for garments Ceramic platinum-gold coating which adheres to ceramic and glass surfaces An arsenic compound reactive with metal oxides under organic coatings Useful in bonding polyacrylate to itself or to other substrates Formulated to be self-extinguishing upon removal of a flame source
Forms complexes with most polyvalent metals other than alkaline earths For use in coil-coating and metal-finishing enamels Controls the accumulation of pitch during the papermaking process
Available in commercial quantities unless otherwise noted.
NEW EQUIPMENT Liquids sampling instrument designed to take noncontaminated samples is offered by Welles Products, Inc., of Roscoe, 111. The Plexiglas sampling chamber of the KH-400 is opened by depressing a thumb lever at the top. When the desired depth is reached, a sharp tug on a cord snaps the instrument closed, trapping the sample. E 30
Automatic high-low liquid level control is offered by Dynasonics Corp., of Syosset, N.Y. The Liquiswitch Model C 200 is a dual-probe unit which provides two-level control with a single solid-state controller, Dynasonics says. E 31
Sensing indicators that activate integral and/or remote signals to warn of excessive vacuum in hydraulic 52
C & E N J A N . 25, 1965
and air intake systems are available from Standard Products division of Michigan-Dynamics, Inc. According to the Detroit, Mich., company, the Series LH indicators are specifically designed to warn of reduced system efficiency and abnormal vacuum levels caused by contaminated filters. E32
Liquid hydrogen level indicating system has been developed by Cryogenics, Inc., of Baileys Crossroads, Va. The system, Model 900 1-2, is a two-channel, fixed-point indicator which provides accuracies of ±0.250 in. E33
Resin-impregnated filter tube is offered by Commercial Filters Corp. Resin bonding gives the tube a greater resistance to compression than have conventional tubes, the Lebanon, Ind., company says. The coreless
honeycomb filter tubes are available in 10-, 20-, and 30-in. lengths for filtering paint and other viscous fluids. E34
Radiation counting system has been designed specifically for paper-strip radiochromatography by Nuclear-Chicago Corp., of Des Plaines, 111. Model 1002 Actigraph III combines the functions of paper transport, radioactivity detection, and data recording in a compact desk- or bench-type console. E 35
An automatic buret which uses a finely ground piston that rides freely in a precision bore tube is offered by Advanced Instruments, Inc., of Newton Highlands, Mass. Accuracy of repetitive delivery is 1 part in 10,000 and calibration accuracy is 1 part in 5000, Advanced Instruments says. E 36
IF YOU MIX THERE IS NOW A PROVEN REASON TO CHANGE
THE
LITTLEFORD-LODIGE PRECISION MIXER
PROCESS PROVEN! ...The Littleford-Lodige Mixer has proven itself in a wide range of industries where the mixing and blending of solids, liquids to solids, coatings, is the requirement... including Chemicals, Plastics, Foods, Detergents, Cleaning Compounds, Insecticides, Rubber, Ceramics, Powdered Metal, Dyes and many others.
PROCESS PROVEN! A Littleford-Lodige Mixer assures an absolute homogeneous mix in a fraction of time heretofore required. Substantially reduces labor and material handling costs. Eliminates the need for multiple equipment... and multiple operation. Insure thorough, but gentle mixing action.
• Mixing not dependent on gravity. • The fastest of all mixing cycles. • Complete and total mixing. • Dust free mixing. • Safety Engineered. • Batch, Continuous flow and Laboratory series available in wide range of sizes.
^9C^_
MIXING VESSEL, PLOWS AND CHOPPERS — Illustrated are plow shaped mixing tools inside horizontal mixing vessel. Optional rotating chopper blade assembly controls particle size. LITTLEFORD
BROS., I N C . , 4 5 3
HURLING AND WHIRLING — Illustrated is unique hurling and whirling action inside mixing vessel . . . gives total but gentle mixing action not dependent on gravity.
MIXER—Shown is Model FKM600-D(2Z) batch type mixer equipped with plow shaped mixing tools and two optional chopper assemblies. E. PEARL S T . , C I N C I N N A T I , OHIO
45202,
AREA CODE 513 — 6 2 1 - 7 4 1 1
Brown & Root is tough on... """C--1., **, \
Brown & Root! When a Brown & Root job is completed it will pass anyone's white glove inspection. After 50 years in the business we have long since found it's best to do things right the first time. This way you save time, money and . . . reputation. A Brown & Root takes full responsibility for its jobs. We rarely sub-let portions of a project. This cuts off the time-honored practice of passing the buck in case of failures, but we prefer it that way. A We always strive to be "ahead of schedule and below the estimate." This is why we have so much repeat business. We will be happy to discuss your project, with no obligation, of course.
Crude distillation and vacuum unit by Brown & Root
Petro-Chemical complex by Brown & Root
P. 0. B O X 3, H O U S T O N , T E X A S 7 7 0 0 1 NEW
YORK
54 C&EN
• THE HAGUE
• LONDON
• EDMONTON
•
CABLE ADDRESS:
• CARACAS
• MONTREAL
BROWNBILT • SAO PAULO
•
WASHINGTON
NEW CHEMICALS
quires no retention aid as do conventional turquoise dyes. C 61
High-purity 3-methoxypropylamine is
now available in commercial quantities from Eastman Chemical Products, Inc. According to the Kingsport, Tenn., company, 3-MPA is used as a component in the emulsifier system of anionic floor polishes. It can also be used in the metal, petroleum, and textile industries. Activity of 3-MPA comes from the presence of both amino and ether groups. C 60
Water
treatment
conditioner
for
cleaning boilers, recirculating systems, and hot-water tanks is available from Magnus Chemical division of Economics Laboratory, Inc. (Garwood, N.J.). Magnatrol No. 2 is a concentration of organic sequestering agents in a liquid form. The product has a broad range of action for removing soil, sludge, and scale. C 62
CONE-PLATE VISCOMETER
Turquoise dye for paper products is
commercially available from National Aniline division of Allied Chemical. According to the New York, N.Y., company, fast turquoise PT doesn't bleed in hot water, strong soap solutions, or other media. The dye re-
Further information on keyed Equipment and Chemicals items is readily available . . .
j I j
Use handy coupon on page 56
\ !
January 25, 1965
Readers' Information Service
Use this handy self-ma Her to obtain further information or literature. Simply mark the items desired, fill out the information requested, clip the coupon, fold, staple,and mail.
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Engineering and Construction Food and Kindred Products Textile Mill Products Paper and Allied Products Government Chemicals and Allied Products Elastomers, Polymers, Plasticizers Drugs Detergents, Cosmetics, Specialties Paints, Varnishes, etc.
FERRANTI-SHIRLEY
) Petroleum Ref., Asphalts, Lubricants L ( ) Rubber and Plastic Products M ( ) Independent Laboratories N ( ) Consultants 0 ( ) Primary Metal Industries P ( ) Fabricated Metal Products Q ( ) Machinery and Equipment R ( ) Transportation Equipment S ( ) Instruments and Controls T ( ) Education K
(
An important instrument for measuring materials such as resins, gums, adhesives, starches, color pigments and slurries. Basic components are a cone with a very small angle (0.3°) and a flat plate. Cone speed ranges are variable from 0.1-10, 1.0-100, and 10-1000 R. P. M., providing continuously variable shear rates between the limits of 2xlO J and 2xl0 4 reciprocal seconds, with higher resolutions available at the lower ranges. A ten turn potentiometer and velocity servo system provide accurate control of cone speed. The plate position is fixed during operation. The 0.0001" gap between cone apex and flat plate is automatically maintained by an electronic gap setting device. Cleaning is extremely simple. About 0.5cc of material refills the instrument. A capstan and multi-start lead screw lowers or raises the plate. Precise repositioning at the raised position is assured by design features. As the plate is raised to operating position and locked into place, the material to be studied is automatically evenly distributed throughout the narrow measuring gap. The material measured will undergo a uniform rate of shear, since the ratio of the cone velocity to the distance between shearing surfaces will remain constant from the apex of the cone to the outer cone periphery. The temperature of the small volume of sample being sheared is controlled by passing a suitable fluid through the plate at temperatures up to 200°C. Thermocouples located in the plate, but thermally insulated, continuously monitor the sample being sheared for temperature gradients. The Ferranti-Shirley Cone-Plate Viscometer has been designed to permit laboratory or quality control measurements of complex nonNewtonian systems. Operators have found this instrument simple to operate and programs are rapidly and accurately completed with minimum supervision. Accessories available include: • Automatic Control Unit • X-Y Recorder • Circulating Thermostatic Bath • Thermocouple Potentiometer. Scientific reprints and illustrated literature are available on request.
IFerranti ELECTRIC, INC.
H
I INTERNATIONAL
DIVISION
1 FAIRCHILD COURT PLAINVIEW, L.I., NEW YORK. 11803 Telephone: 516 WE I Is 8-7500
JAN.
25,
TWX 516-433-9160
1965
C&EN
55
