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E. K. Landis, Philadelphia, Pa. (communication to the Secretary) : Mr. Firmstone's paper is of great interest; but he has unfortunately otnitted to state the most important point, viz., the percentage of sulphur in the two materials he compares; and this omission vitiates the conclusions which he draws. Comparing by grade, instead of silicon-contents (as in his Table III.), the iron made using limestone with that made using dolomite, we find for gray-forge the average of four analyses under limestone to be, Si, 0.644; S, 0.089 ; while one analysis under dolomite gives Si, 0.508 ; S, 0.070. For No. 2 iron, the limestone flux gives, as an average of 19 analyses, Si, 1.107; S, 0.051; while the average of 4 analyses made with dolomite flux gives Si, 0.630; S, 0.056. It will be observed, that no No. 1 pig is given under limestone, while 14 analyses appear under dolomite, averaging Si, 0.950 ; S, 0.028. As nothing is said about changed conditions, it is Fair to presume that the ore and fuel, as well as the blast-temperature (which is stated to have been uniform at about 750' F.) remained practically the same; and since the sulphur in the two fluxes is not given, it is impossible to know whether the lower sulphur for equal silicon-contents is due to the use of dolomite or to other conditions. The use of dolomite would produce a more fusible cinder, and the furnace would be hotter than when using limestone; therefore, we might expect to see a grayer iron. The amount of So. 1 iron made with dolomite seems to confirm this supposition; and, under these conditions, we might expect more of the sulphur to be volatilized, and to pass off in the gases. The easier fusibility of the cinder would also permit more rapid driving; and this should reduce the amount of silicon and sulphur in the iron, as the amount of reduced metalloids in the pig is directly proportional to the length of time it remains in the reducing-zone.

Jan 1, 1895

John S. Kennedy, Chamhersburg, Pa. (communication to the Secretary): The washing-plant described by Mr. Johnson is a good illustration of the advantages derived from a well-designed and care-

Jan 1, 1895

Philip Argall, Denver Col. (communication to the Secretary): Dr. Raymond claims (Trans., xxiii., 560)) that my statement (p. 557) regarding the crystallization of iron "is beyond question incorrect." He says: "It is not even settled that vibration will crystallize iron under any conditions." While admitting that authorities differ on the possibility of cold crystallization of iron, I believe it is a settled and undisputed fact that vibration in the presence of heat will crystallize iron. Bloxam and Huntington say :* " Vibration assists 'in converting fibrous metal (iron) back into a crystalline state when heated, a lower temperature sufficing than in the absence of vibration." Mr. A. F. Hill, summing up a very exhaustive review upon the crystallization of iron and steel, pronounces against crystallization, but only at temperatures below 900' F. Mr. Howe, discussing ,the breakage of a 20-foot porter-bar with a crystalline fracture, suggests that it was attributable to heat, jointly with the jar. We see, then, that vibration of heated iron bars will induce crystallization and consequent change of structure. Referring to my statement, I wish to point out, that I was discussing the vibration of stamps arid should have said, "vibration under all such conditions," etc. That is, vibration attended with sharp blows, such as a stamp-stem is subjected to, will crystallize iron; yet I believe that intense vibration under any condition will

Jan 1, 1895

By Henry Louis

The present paper comprises two parts, which have but little con nection with each other. The first is practically a continuation of the investigation on the specific gravity of gold liberated by means of acids from its alloys, on which subject I had the honor of presenting a brief note to the Institute in 1893 (Trans., xxii., 117); the second describes a series of experiments on the behavior of amorphous gold under the action of heat. By the kindness of Prof. W. C. Roberts-Austen, C.B., F.R.S., chemist to the Royal Mint, I have been permitted to conduct these experiments in the mint assay-office, all the splendid resources of which institution were freely placed at my disposal. I desire at the outset to express my obligations to Prof. Roberts-Austen and to all the staff of the mint assay-office for their kind assistance at all stages of my experiments. I.—The Specific Gravity of Gold in Alloys. In the note already referred to, I published my discovery that the gold left on dissolving out the silver from an alloy of gold and silver (which I shall here term " residual amorphous gold ") has a higher specific gravity than ordinary molten gold. I also pointed out that I had worked on very small quantities of material and with balances and weights on the accuracy of which I could not implicitly rely, and that in so far my numerical data were inconclusive, although I had but little doubt of the correctness of the broad fact. The experiments now recorded were made under the most advantageous circumstances and with various refinements. Particularly, I found that the ordinary form of specific-gravity bottle was responsible for several small sources of error; and I accordingly designed an improved form (Journal of the Society of Chemical Industry, April 30,1894, vol. xiii., p. 322), which I used for this work. The

Jan 1, 1895

By H. Van F. Furman

TO those engaged in the purchase and sale of gold- and silverores, mattes and bullion, the frequent differences in the gold- and silver-contents, as reported by different assayers, is a source of much annoyance and expense. The desirability of uniform methods of assay has long been recognized by certain refiners who specify in their bullion-contracts the method to be adopted in assaying the bullion. One large producer of base bullion employs at each refining-works with whom it has a bullion contract an assayer whose duty it is to see that the bullion is sampled and assayed according to contract-specifications. For the assay of gold- and silver-bullion, standard methods are now generally adopted; the reeult being that differences seldom occur. While we cannot hope for anything near perfection from fireassay methods for ores, mattes and base bullion, as carried out cornmercially, such methods may be made to yield results which answer all commercial requirements, and they will probably be retained for obvious reasons. The object of the present paper is to point out some of the sources of error and to show the importance of more uniform methods of assay and close attention to the details of the work. The sources of error in the assay of ores and mattes are: improper sampling; losses of the precious metals during fusion, scorification and cupellation; imperfect elimination of the base metals on the cupel and imperfect extraction of the silver during the parting in nitric acid. It is not the object of the present paper to enter upon the subject of sampling; but a few remarks may be of value. There has been considerable discussion recently in Colorado upon the frequent differences which occur in the assays of Cripple Creek gold-ores, and these differences have been attributed to various causes. The writer is informed by two of our most prominent smelters that since they have adopted 100-mesh screens (the general practice is 80-mesh) the

Jan 1, 1895

By C. A. Stetefeldt

In my paper on "The Consumption of Fuel in the Taylor Gas-Producer Plants at the Aspen and Marsac Mills" (Trans., xxiii., 134), I mentioned that in the plant which I had designed for the Ontario mill, the gas-tubes were to be covered with thin, corrugated sheet-iron, over which a coating of asbestos-magnesia would be spread in order to effect a good insulation and keep the gas as hot as possible. At the Ontario mill, two Stetefeldt furnaces and two revolving driers are fired with gas. One furnace is connected with a Taylor producer of 5 feet diameter, and the other furnace and the two driers are heated by the gas from a Taylor producer of 7 feet diameter. In the latter case the gas-tubes are necessarily somewhat long, and the cleaning of them takes time. In order to prevent overheating of the tubes during that operation, it has been found advantageous not to provide them with an insulating covering. If a tube becomes red-hot at any place by the burning of soot, this is at once observed, and the tube is closed until it cools down. The tubes con-

Jan 1, 1895

By N. Djilali

Many of the transport phenomena encountered in proton exchange membrane fuel cells occur intrinsically at the microscale level. Physically representative models that fully account for the salient physico-chemical and transport processes in PEM fuel cells are necessary to achieve truly predictive models that can be used with confidence to: (i) gain a better understanding of in-situ processes and couplings, (ii) explore new concepts, and (iii) support design and optimization. The development of more general, rationally based macroscale models requires use of knowledge on the microscale level to provide guidance, and to determine the required parameters and coefficients (model "constants"). In this paper we present a new membrane transport model, the binary friction membrane model (BFM2), recently developed to account for coupled protonic and water transport in polymer membranes. This general model is based on rational and physical consideration, removes several of the limitations of the empirical models used to date, and is formulated for all purfluoro-sulfonic acid membranes. The use of the BFM2 in a fuel cell model is illustrated highlighting significant performance predictions compared to existing empirical model. The second part of the paper addresses the fundamentals of two-phase transport in hydrophobic gad diffusion media. Computational and experimental visualizations resolving the microscale dynamics of water transport between the fibres of a GDL are presented, revealing transport mechanisms that are, contrary to assumptions used to date, dominated by fingering and channeling.

Jan 1, 2005

By O. A. Bascur

Current competitive demands on the process industries stimulate the need for improved operating efficiencies and compliance to stricter governmental regulations. Emerging information technologies allow narrowing the gap between management business objectives and the process control level. Benefits come from enhanced energy management, operating costs reduction, enhanced scheduling of activities, reduced quality giveaway, enhanced market driven production and enhanced decision making. Plant management systems integrate economic performance monitoring by controlling the business rather than just throughput and product quality. Sound business based decisions about how to operate the plant can be achieved by adequate dynamic performance monitoring at the plant level and the enforcement of the desired targets at the process control level. This paper describes some of the key requirements to implement a process management system to meet stricter process performance standards. Extensions are made to facilitate conforming with regulations established by various governmental and industry monitoring agencies.

Jan 1, 1993

By Kapila Pathirage, Michael S. Schultz, Gregory Sanders, Ulf G. Gwildis

Adequate understanding of the subsurface conditions along the alignment of a planned tunnel is key for managing project risk. For achieving this understanding, geotechnical borings are conducted during design. Where their spacing cannot reduce the risk of encountering differing site conditions (DSC) in-between borings to an acceptable level, supplemental exploration methodologies or data evaluation approaches may be required to bridge the data gap. This paper compares the exploration design approaches of recent tunnel boring machine (TBM) and microtunnel boring machine (MTBM) projects in the quaternary deposits along the Eastern Seaboard, the glacial geology of the Pacific Northwest, the sedimentary rocks of the South, and metamorphic rocks in western Germany, describing their respective effectiveness of managing DSC risk.

Dec 1, 2022

By Karl K. Bagger, Felipe Bertelli

The competitive scenario of steel industry requires studies and developments to improve manufacturing processes focusing on increasing productivity and reducing costs. The practice of coating rolls for cold rolling with the chrome aims to increase the rolling campaign, reducing their wear by increasing the surface hardness, which guarantees a greater homogeneity in the surface of the rolled products. The present paper presents a study on the effect of the chromium coat on a forged steel rolls on the wettability of a SkinPass solution. The hardness of the coated layer and the contact angle were measured for two concentrations of solution on two types of surfaces, comparing the coated and uncoated surfaces. The results show that there is an influence of the coating on the wettability of the fluid when comparison are made with chrome coated and uncoated materials, being verified through tests in Goniometer. The productivity of the coated rolls showed higher productivity than the uncoated ones.

Oct 1, 2019

By AIME AIME

IT IS impossible in this short sketch to give a detailed description of each part of the plant at Bethlehem, therefore, only such facts will be touched on as are necessary to give a general idea of the works. The extent of the plant, and the fact that the units making up the various departments are located in different parts of the works, make it impracticable to mention the departments in any regular order with regard to their location. They are, therefore, mentioned approximately in the order of their relation to each other with reference to their functions in the making of the various products.

Jan 1, 1924

By Ben Blaschuk

The Bagdad solvent extraction plant was commissioned in 1969 and was the second solvent extraction-electrowinning (SX-EW) operation to be built following the Ranchers Bluebird SX-EW plant near Miami, AZ. The current operation still resembles its original form, with four independent sections that run in parallel with each consisting of many long and narrow settlers. Through its 40-year history, the Bagdad SX circuit has experienced a range of pregnant leach solution flows and grades. The unique design of the Bagdad circuit has allowed for numerous configuration changes to accommodate the changing operational conditions, while maintaining an extraction recognized in the industry as excellent.

Jan 1, 2011

The equipment and general smelter layout for the Mount Isa Copper Smelter were designed by engineers associated with the American Smelting and Refining Company and by Mount Isa staff engineers. The final notice of site was dictated by the need for 'building the smelter near the existing Mount Isa power house to enable full use to be made of the steam from the waste heat boilers. Although much excavation work was necessary before concrete foundations could be poured, the location lends itself to further expansion should it become necessary. The plant is designed and constructed to involve straight line smelting operations which include the following major steps in the overall scheme.1. Charge make-up.2. Roasthig.3. Reverberatory smelting.4. Converting.5. Refining.6. Casting.CHARGE MAKE-UPA system of proportioning bins is provided for preparing the feed mixture for the roasters, Sulphide concentrate containing 24% copper wiil be delivered by belt conveyor from the filter plant to the smelter storage patio. This is a large roofed concrete floor that provides a maximum storage capacity of 8,000 tons of concentrate. Eight proportioning bins located below but adjacent to the south end of the patio will be used for actual charge make-up from which concentrate, ore and flux will be proportioned to the feed belt and conveyed to the roaster feed hoppers. Four of the proportioning bins, 80 tons capacity each, will receive...

Jan 1, 1953

By Frederick W. DeVries

The author was invited by "60 Minutes Australia" to provide on-site technical background on cyanide, mining, and the environment, in their investigation of the January 30, 2000, spill at the Aurul gold-recovery site in Baia Mare, Romania. Some remarks on the incident ?and its implications surround a showing of the fourteen-minute telecast. The thrust of the TV reporter was that aspects of the dam implied the owners' use of standards Jess than would have been met for installations in technologically more advanced locations (like Australia). As a result, the public-relations impact is one of embarrassment for the world mining industry.

Jan 1, 1998

By Floyd Kelley

THERE is an ever-increasing demand for furnaces with controlled atmosphere, due to the large quantities of steel being used in the automotive industry, such as the .high-chromium stainless irons, the 18 Cr, 8 Ni stainless iron and low-carbon steel sheets. The difficulties involved in the annealing of such materials, if they are to be kept absolutely free from oxidation, are many. It is possible to bright-anneal these steels in small laboratory hydrogen furnaces, using specially purified hydrogen and taking some additional precautions. In the first place, the insulation, usually of alumina or magnesia, holds small amounts of water vapor, which it is almost impossible to remove completely. Secondly, there is always condensation of water vapor in the cooling chambers of such furnaces, and with the continuous circulation of the hydrogen gas in the furnace, the water vapor is carried from the cooling chamber back into the heating chamber. This water vapor oxidizes the charge. Lastly, the supply of moisture is made sure by the diffusion of small amounts of air from the atmosphere into the furnace against the pressure of the hydrogen. The oxygen combines with the hydrogen and forms more water. Under such conditions there is, little gained by using specially purified gas, because it becomes contaminated after reaching the furnace.

Jan 1, 1931

By Arturo Ressi di Cervia

Construction of the drilled shafts for the Brightman Street Bridge Replacement Project were not only challenging due to working over the water but were also challenged by changed soil conditions, concurrent work being performed by an adjacent contractor on the same project, environmental restrictions and severe winter conditions. A total of 36 x 8 feet diameter drilled shafts with 7.5 feet rock sockets were installed for the East and West bascule piers. This project also included Osterberg Cell load testing on two production drilled shafts at each the East and West bascule piers. The results from the load test program were used to fine tune the design of the drilled shaft rock sockets. From a constructability standpoint the reverse circulation drilling method with a pile top drill rig proved to be an excellent choice for drilling the overburden and rock sockets of the large diameter deep drilled shafts.

Jan 1, 2003

By Jeffrey M. Taylor, Arturo Ressi di Cervia

"Construction of the drilled shafts for the Brightman Street Bridge Replacement Project were not only challenging due to working over the water but were also challenged by changed soil conditions, concurrent work being performed by an adjacent contractor on the same project, environmental restrictions and severe winter conditions. A total of 36 x 8 foot (2.44m) diameter drilled shafts with 7.5 foot (2.31m) rock sockets were installed for the East and West bascule piers. This project also included Osterberg Cell load testing on two production drilled shafts at both the East and West bascule piers. The results from the load test program were used to fine tune the design of the drilled shaft rock sockets. From a constructability standpoint the reverse circulation drilling method with a pile top drill rig proved to be an excellent choice for drilling the overburden and rock sockets of the large diameter deep drilled shafts. INTRODUCTIONThe replacement Brightman Street Bridge spans the Taunton River between Fall River and Somerset in Massachusetts.The new crossing is located approximately 1500 feet (450m) upstream from the existing Brightman Street Bridge, which was built in 1908. The new mainline bridge includes nine spans totaling 1725 feet (525m). A bascule type moveable span will be located in the middle of the Taunton River and provide a 200 foot (61m) open channel centered about the 400 foot (122m) navigational channel. The bascule span, which has a span length of 409 feet (124.7m), will be a trunnion-type four leaf structure with a solid deck. A site plan is shown in Figure 1 Contract 3, which includes construction of the foundations for the East and West bascule piers, was bid on December 19, 2000 and was awarded to Modern Continental Construction Company (MCC) on January 24, 2001. MCC in turn awarded the subcontract for the installation of the drilled shafts to TREVIICOS Corporation, which started mobilizing in June of 2001.The scope of work for the drilled shafts of Contract 3 consisted in installing 18 drilled shafts in three rows on each side of the river to support the bascule piers located in the middle of the Taunton River.The foundation plan for the bascule span is shown in Figure 2."

Jan 1, 2004

By L. W. Beckstead

In a conventional zinc refinery plant, zinc concentrates were roasted at 950°C. The calcine was ground and leached in a series of leaching vessels using sulfuric acid. The pH in the first leaching vessel was maintained at 2.5, while the pH of the solution exiting the last vessel was about 5.4. The leached residue typically contained (in percent) 0.1 Ag, 0.2 As, 0.7 Cd, 2 Cu, 15 Fe, 10 Pb, and 15 Zn, and it was classified as hazardous material according to the EP-toxicity test. In order to make the residue non-hazardous, and to recover most of the metal values from the residue, a brine leach process was developed. The process consisted of leaching the zinc leach residue in CaCI, brine solution at pH 2 for 1 hour at 90°C. Silver extraction was about 95 percent, while lead, copper, cadmium, zinc, and iron extractions were about 80, 50, 50, 30, and less than 0.5 percent, respectively. More extreme conditions of acidity could have been used in the leaching stage to increase zinc dissolution, but iron dissolution would have significantly increased which would have complicated subsequent recovery steps. The leached and washed residue passed the EP-toxicity leach test and could be disposed as non-hazardous. Silver, copper, and lead in the leach solution were recovered by zinc cementation, while zinc and cadmium were recovered by sulfide precipitation. The resulting solution can be recycled in the process after magnesium precipitation.

Jan 1, 1993

By Derrick Dasenbrock, Mary C. Nodine, Benjamin Rivers

Up to 50 percent of major infrastructure projects suffer impacts to schedule or cost due to geotechnical issues, many of which correspond to risks related directly or indirectly to the scope and quality of site characterization work. The Federal Highway Administration (FHWA) in coordination with industry organizations seeks to address this issue through Every Day Counts (EDC), a program that identifies and deploys proven, yet underutilized innovations at the project level to save time, money and resources. The A-GaME (Advanced Geotechnical Methods in Exploration) is one of the innovations supported under EDC.

By Delio Amorim

Industry 4.0 concepts is the new biggest challenge on the industry nowadays and every company in every industry in every part of the globe is looking to implement this somehow on their factories and machines. To do that on the newest long rolling mills, that brings already onboard state-of-the-art technologies, is for sure a challenge of machinery builder industry, but how to become the long rolling mills built on 70’s, 80’s or 90’s part of this innovation process and connected to the new trends? This is the main mission here, to show some examples of applications that goes in this direction.

Oct 1, 2019