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By Long Meng, Kuiyuan Chen, Zhe Wang, Yiwei Zhong, Zhancheng Guo

Printed circuit boards (PCBs) contain plenty of toxic substances as well as valuable metals (e.g. Pb and Sn). In this study, supergravity as a novel technology was used to separate and recover different mass ratios (Pb/Sn) of Pb-Sn alloys from PCBs. In a supergravity field, liquid metal phase can permeate from the solid particles, and based on this, 200, 280 and 400 °C were selected to separate Pb and Sn from PCBs. The results showed that the gravity coefficient only affected the Pb-Sn alloy weight, and did not change the mass ratio of Pb/Sn. With the increase of gravity coefficient, the recovery values of Pb and Sn were increased. In the separation process, under the gravity coefficient of 1000 and separation time of 2 min, the recovery values of Pb were 33.13, 38.86 and 50.48% at the temperature of 200, 280 and 400 °C, respectively, and the recovery values of Sn were 23.31, 32.57, and 40.81%, respectively, and the mass ratios of Pb/Sn in the Pb-Sn alloys were 0.55, 0.40 and 0.64, respectively. This provided a new approach to recycle Pb and Sn from PCBs.

Mar 1, 2018

By Qingsheng Liu

A new method of recycling aluminum dross for preparation Al-Si-Ti alloy was studied in this paper. This was carried out in two processes. first the aluminum doss was pretreated by leaching and calcining process, the fine purity and phase of the intermediate oxide powder up to electrolysis demands, then, could be obtained when aluminum dross after washing have been leached for 2h at 100? in 20% hydrochloric acid and calcined for 2h at 1200?, which was treated by cryoite-based molten salt electrolysis. Finally, the Al-Si-Ti alloy was successfully obtained through electrochemical co-deposition in the cathode shows a typical as-cast microstructure. This new recycling method can produce high quality alloy and may bring remarkable economic and social benefits.

Jan 1, 2010

By AIME AIME

THE annual fall meeting of the Institute of Metals and the Iron and Steel divisions, in conjunction with the American .Society for Steel Treating and the Metal Congress and Show, at Boston was from many standpoints the most successful we have had to date. While many faces were missing from the various gatherings, the Institute registration reached the high mark of 324 members and guests. Cooperating with the Steel Treaters were also the American Society of Mechanical Engineers, the Society of Automotive Engineers and the American Welding Society. ,The meeting was, as usual, a three-ring circus with technical sessions 'galore, plant .trips, visits to the Exposition, social events such as lunch- eons and dinners as well as entertainment for the ladies present.

Jan 1, 1931

By Walter S. Bergholz, Michael L. Schreder

"Since Escondida began operations in fiscal 1991, a series of aggressive expansion projects have enabled market share to be increased and ever larger profits to be realized. This was possible due to the very large size of the ore body and its high grade - averaging 2.7% copper from startup through fiscal 1997. The situation has now changed: ore grade is falling rapidly and is projected to be only 1.55% by 2003. Since revenue is directly proportional to ore grade, while costs are proportional to quantity of ore processed, profits will begin to fall dramatically. The Phase IV Expansion Project is intended to forestall this drop in profits by increasing ore processing capacity by over 85%.The Phase IV concentrator is designed for a nominal capacity of 110,000 MTPD and the key to achieving this value is through the proper design of the grinding circuit. This paper presents the general design criteria for the grinding circuit, as well as a description of the facility.INTRODUCTIONThe Phase IV Expansion Project consists of a new copper concentrator located 8.5 km south of the existing operations, a new tailings disposal and water reclaim system, a new concentrate slurry pipeline to the coast, and added concentrate handling capacity at the port of Coloso. The new concentrator has a nominal capacity of 110,000 tonnes per day (MTPD), compared to the existing concentrator’s capacity of 127,500 MTPD. The Laguna Seca concentrator is based on using the largest and most efficient ore grinding mills now available.The concentrator has been designed for a 110,000 MTPD nominal capacity. The process design criteria for the Phase IV project were established from in-house operating information and from test work. Unlike a green field project, Escondida already had an operating plant and it processes ore from the same pit that feeds the Phase IV plant. It is expected that the current mineralization will be similar for the first 6 years of operation of the new project. Therefore, some of the current plant operating conditions were incorporated directly into the design criteria."

Jan 1, 2004

By Edward J. Sterne

Several shale-hosted Pb-Zn-Ag deposits have been discovered in the northwestern Brooks Range, Alaska. Best known among these are the Red Dog, Drenchwater Creek, Lik, Ferric Creek, Hot Dog Creek, and Competition Creek deposits. They occur in a tectonically disturbed sequence of of Mississippian to Triassic shales, argillites, and cherts, and most are spatially associated with volcanic rocks. The sulfides are hosted in shales as disseminations, banded layers, massive lenses, and crosscutting veins. Detailed geologic descriptions of sulfide prospects in the Brooks Range were given by Tailleur (1970), Nokleberg and Winkler (1978), and Plahuta and Robinson (1979). Lange et al. (1980) discussed the formation of the deposits, the nature of the mineralizing solutions, and the temperature of formation on the basis of sulfur isotope studies. More recently, Harrover et al. (1982) detected a correlation between sulfide mineralization and high-temperature formation of charts associated with the sulfides by oxygen Isotope and chert crystallite size determinations.

Jan 1, 2013

By Joseph L. Condon

High-speed movies were taken of crater experiments in two-dimensional plates of Tennessee marble to study craters being formed primarily by stress-wave action. The contribution of gas action to the cratering process was minimized because the two-dimensional models did not contain the expanding gases from the explosive. Four burdens were studied for solid plates and one burden for a segmented plate. After cratering, the plates were reassembled for dye penetrant studies of fracturing. Flyrock velocities were calculated and related to the degree of fracturing, and compared with those from quarry shots. In general, the smallest burdens produced the highest flyrock velocities and the least amount of fracturing. Flyrock velocities compared favorably with initial flyrock velocities in quarry blasts, but did not show step accelerations due to gas effects as did the quarry blasts. The test with a segmented plate was used to simulate cratering in a jointed material and showed that stress-wave effects can be important for crater formation in jointed rocks.

Jan 1, 1972

By Francois E. Heuze

The mined geologic burial of high-level nuclear waste is how the favored option for disposal. The underground repositories must keep the waste away from the biosphere for very long times - several thousands to tens of thousands of years. Also, access must be maintained to the vaults for several tens of years, so that the waste can be retrieved, if necessary. Both the excavation of the underground chambers, and the radiogenic heating will disturb the rock mass. The overall rock mechanics problem is to understand and predict the processes associated with these perturbations, and their impact oh the isolation and containment of the waste (3)**. The specific rock. mechanics issues which have been identified for the three candidate hard rocks (basalt, granite, and tuff), are summarized in Table 1. The table also indicates the level of adequacy of our knowledge in the areas of the various issues. Such an evaluation is consistent with the general consensus of the rock mechanics profession, as explained in several key reports and publications (1 to 11). The main shortcomings of today's rock mechanics for waste repositories can be summarized as: ? lack of resolution for remote mapping of fractures in rock masses ? great difficulty in testing large volumes of rocks to determine their mechanical properties.

Jan 1, 1981

By L. C. IlsLey

[The last previous Bureau of Mines publication relative to details of permissible methane detectors (Bulletin 331, published in 1930) describes detectors of four different types, namely flame, combustion, catalytic, and a combination Wheatstone-bridge axed catalytic type in which catalytic action at the surface of a platinum filament when in methane causes a change in the temperature and resistance of the filament, thus unbalancing the bridge circuit and giving a reading proportional to the methane concentration. Three detectors of the latter type have been approved since 1933. A brief description of each follows: U. C. C. Detector Approved No. 902, covering the U. C. C. indicating detector, as described in Bulletin 331, was entered January 27, 1330, to cover important chances in design that permit checking; the calibration of the detector at any time, whether in gas or fresh air. Essential features of the detector are shown in figure 1.]

Jan 1, 1937

By Don Welch

Pressures for change ?Land use constraints ?Project financing ?Local communities ?Environmental issues ?Sustainability requirements ?Stricter regulatory procedures ?Technical excellence ?Reduce risk ?Impacts of failure & non-compliance

May 1, 2010

By Tiezheng Li

Keywords: Laminate Composites; Mechanical Behavior; Damage Evolution The mechanical performance of Ti-6-4-Al3Ti metal-intermetallic laminate (MIL) composites synthesized by a reactive foil sintering technique was evaluated. Crack morphology of untested Ti-6-4-Al3Ti MIL composites has been characterized by optical microscopy. Mechanical tests were performed on Ti-Al3Ti metal-intermetallic laminate (MIL) composites and pure Al3Ti, and the principal mechanisms of damage initiation and accumulation were identified experimentally. The elastic properties and anisotropy of the laminates were calculated and successfully compared with Resonant Ultrasonic Spectroscopy (RUS) measurements. The effect of residual stress on the fracture toughness of the Ti-6-4-Al3Ti MIL composites was analyzed.

Jan 1, 2005

By S. T. L. Harrison, M. A. Fagan-Endres, M. D. Odidi

This paper investigated the ability of eight common hydrodynamic models – tanks in series (TIS); three compartmental model configurations (Comp-1, Comp-2 and Comp-3); advection dispersion (AD); piston exchange (PE); piston exchange-diffusion variant (PE-D) and piston dispersion exchange (PDE) – to simulate residence time distribution (RTD) data generated from tracer tests conducted on a packed bed composed of different size fractions of malachite ore. The chosen materials were packed into 0.1 m internal diameter columns to a depth of 0.155 m and drip irrigated at 5.11 L/ m2.h. The four size fractions tested were: 1 – 2 mm, 2 – 2.8 mm, 4.75 – 5.6 mm and 13.6 – 16 mm. Step-up tracer tests were conducted using potassium chloride. The results showed that an increase in the particle size of the malachite ore had little effect on overall bed porosity but resulted in significantly lower values of liquid holdup. Two of the monoporosity models tested, TIS and Comp-2, were the most affected by the changes in bed size fraction due to their inherent inability to cope with high degrees of non-ideal flow present in the larger particle systems. The dual porosity models performed relatively better with the dominant trend being a reduction in dynamic to total liquid holdup as particle size increased. Of all the models tested, the PDE and TIS models were the best and worst performers respectively, with R2 values averaging at 0.997 and 0.679 across all experiments respectively. Though the Comp-1, Comp-3 and PE-D models also performed well, the addition of the dispersion coefficient to take the axial spread of fluid molecules into account added a layer of complexity that allowed the PDE model to perform relatively better than the other dual porosity models. Keywords: Heap leaching, packing material, hydrodynamics, malachite, PSD, modelling

Jan 1, 2020

By James Barr

Geology and Mineralogy1 TENNESSEE phosphates are commercially divided into three varieties: Brown, blue and white. The first two only are now of commercial importance. The white phosphates of Perry county are not being mined at present owing to their pockety occurrence. The white phosphate is Fig. I.-DEPOSITS OF 75 PER CENT. BROWN PLATE ROCK UNDERLAIN BY SAND. the highest grade of the three varieties, running often more than 90 per cent. tricalcium phosphate. The brown rock is found in three varieties, grading from the dense almost vitreous gray rock, 76 to 82 per cent. tricalcium phosphate, down

Jan 9, 1914

By A. M. Brown, P. V. Straznicky

Dimpling as a means of flush countersinking rivets is an old process predominantly used in secondary structures. The introduction of GLARE as an aerospace material has renewed interest in dimpling and its possible application in primary structures. The dimpling process is able to prevent the creation of a machined knife-edge in the thin aluminum plies of the GLARE sheets. In addition, dimpling eliminates the need to use reduced height rivets, such as the NAS 1097 rivet style. This investigation expands on an earlier study into dimpling of GLARE by Rans and Straznicky. In order to tailor the dimpling process to GLARE, FEM simulations were developed. After verification, a study was performed to find the best parameters for dimpling GLARE3-2/l. Coupon fatigue tests were carried out and the dimpled joints demonstrated increased fatigue lives over the conventional machine countersunk joints. Future wide panel fatigue tests are planned to confirm the usefulness of dimpling thin GLARE laminates.

Jan 1, 2006

By M. K. Senicie

IN July, 1937, Asbestos Corporation, Limited, installed an automatic conveyor-belt scale at their King mine, Thetford Mines. The equipment was purchased 'on trial' and its performance has proved entirely satisfactory to the staff. The scale was manufactured by the Toledo Scale Company, of Toledo (Ohio) and Windsor (Ont.) and was installed by one of the Scale Company's engineers. The electrical recording equipment was installed by Keith Mercer, Reg'd, of Montreal, Canadian agents for the manufacturers, the Builders Iron Foundry, of Providence, Rhode Island. The recording equipment consists of a duplex weight-transmitter attached to the scale-head, a duplex totalizer with differential relays, a belt-speed compensator, a rate-of-delivery recorder, and a rate-of-delivery indicator. As it was desired to run the mill at maximum capacity, it was necessary to know the rate of feed at all times, so that any lessening of rate of feed or delays would be recorded and could be corrected. After having determined the rate of feed to the mill (100 per cent capacity), it was required to have weighing and recording instruments which would show: (1) The rate of feed per hour. (2) Any variations .in the load. (3) Any delays and the duration and time of the delays. Rate of tonnage recorders in the mill superintendent's office and at the point of feedi.ng were necessary, as was automatic control between the mill superintendent and the feed man. It was desired to have a permanent record of total tonnage fed per shift or day; weighing and recording mechanism had to have sensitivity to record all previously mentioned conditions. Mechanism had to be of rugged construction, and be so built that it would stay in good operating condition, with the minimum amount of adjustment and supervision.

Jan 1, 1938

By J. H. Holden

Operations involving the processing of coal, oxygen, and steam into synthesis gas by means of two pressure-type gasifiers have demonstrated the effect of heat loss and operating variables on carbon gasified and oxygen and coal requirements. Carbon gasified is the fraction of carbon in the coal that is converted to gas. Oxygen and coal requirement is the quantity of each that is needed to produce a unit volume (M std. c.f.) of carbon monoxide and hydrogen. Operating pressure of the gasifiers ranged from 150 to 300 p.s.i.g. and coal was fed at 200 to 500 lb./hr./cu.ft. of reaction-zone space. Oxygen-to-coal ratios were 8.5 to 10.5 std. c.f./lb. Heat loss and residence time have opposite effects on carbon gasified; increasing the heat loss decreases the carbon gasified, but increasing the residence time (by raising the operating pressure or reducing the coal-feed rate) increases the carbon gasified. The effects of these two factors are difficult to separate because they usually change simultaneously. A comparison of the results obtained from the operation of two gasifiers with different levels of heat loss, however, permitted the effect of heat loss to be separated from that of pressure and coal-feed rate. When the results were deter- mined on the basis of constant heat loss, increase of the residence time increased the carbon gasified until the reaction virtually had come to completion. For example, at 150 p.s.i.g., decreasing the coal-feed ratio from 500 lb./hr./cu.ft. to 200 lb./hr./cu.ft. substantially increased the carbon gasified. At 300 p.s.i.g., however, changing the coal-feed rate had little effect on the carbon gasified because the reaction had almost reached completion and further increase in residence time resulted only in a negligible change.

Jan 1, 1962

By S. Rivard

"This paper demonstrates the selection of grinding circuit technology for a number of recent projects including discussion of the key drivers and the role of energy efficiency. Decreasing head grades combined with a strong and sustained increase in operating costs has forced miners to examine increased project size, increased equipment capacity and efficiency improvements in order to reduce their unit operating costs and improve overall project economics. Comminution energy consumption, safety and capital cost considerations play a critical role in the success of projects. This paper presents some key guidelines for a successful and cost effective comminution circuit design and includes a case study on three projects, outlining the issues and the drivers which led to the ultimate circuit selection and the critical role that energy efficiency played.IntroductionComminution circuits for minerals processing are selected based on their suitability and efficiency in reducing run-of-mine ore to the desired feed size for the downstream process. The input material (ore) properties and downstream process requirements are the key determinants and there are standard approaches for each circumstance.The minerals processing industry has been a fast adaptor of efficiency improvements based on increasing capacity of equipment (e.g. trucks, crushers, mills, pumps) but less successful in adapting radically new technologies that disrupt incumbent flowsheets or processes.The installed power of grinding mills has increased linearly over the past 25 years (Meka & Lane, 2010) and pumps and classification equipment have kept pace. The autogenous grinding (AG) and semi- autogenous grinding (SAG) mills displaced stage crushing as a dominant method of coarse rock breakage in many applications causing crusher manufactures to increase the capacity of cone crushers to meet the competitive demand.Examples of new comminution technology in the 20th and 21st centuries are the development and adoption of cyclone classification in the 1940s (Newtech, 2016), AG milling in the late 1950s, vertical grinding mills in the 1980s, high pressure grinding rolls (HPGRs) also in the 1980s and ultrafine milling technology in the 1990s (Meka & Lane, 2010)."

Jan 1, 2017

By K. Law

"The Hatch Product Transport (HPT) system is a highly flexible and configurable route selection and sequencing system for controlling large bulk material handling facilities. The system has a generic control algorithm that can be configured to suit any material handling facility. It can also be easily reconfigured to cater to plant expansion or modifications without incurring significant disruption to the existing production, costs in testing, and re-commissioning, thus achieving cost savings throughout a facility’s lifecycle.This new material handling control system has been installed at BHP Billiton’s Port Hedland iron ore terminal to facilitate its expansion to beyond 100 Mt output capacity."

Jan 1, 2006

By L. A. Cisternas, A. Lopez-Valdivieso, Y. L. Botero, L. Cortes

In the processing of sulfidic ores, pyrite is usually depressed and ends up in the tailings. However, pyrite is the most common species responsible for acid mine drainage (AMD) due to its spontaneous oxidation. This AMD affects the tailing chemical stability by dissolving some toxic or heavy metals species such as As, Cd, Co, Pb, and Zn, which can migrate into the surrounding ecosystems. Therefore, the strategies to reduce pyrite’s environmental impacts are a crucial point to produce more chemically stable tailings. Consequently, numerous studies have been made to find procedures that could inhibit or restrain AMD. This work aims to develop a procedure for designing conceptual flotation circuits that can produce tailings with low content of pyrite and to assess this type of circuit with traditional flotation circuits. The method consists of applying optimal flotation design where three products are considered: metal concentrate, pyrite concentrate, and tailing with low content of pyrite. Two approaches are considered; in the first, a flotation circuit is designed to generate a concentrate rich in all sulfide minerals and to obtain a tail with low pyrite content. Then, a second flotation circuit is designed for the selective separation of the bulk into metal concentrate and pyrite concentrate. This is called fractional separation design. In the second approach, a flotation circuit design is realised that generate the three products simultaneously. This is called integrated separation design. Both fractional separation design and integrated separation design are assessed in this paper. This methodology is focused on cleaner production (waste prevention and resource minimisation) rather than end-of-pipe technology (treat existing waste). The methodology was applied to a copper sulfide ore from a local company in the Antofagasta region (Chile). This ore contains chalcocite, covellite, iron oxides, and pyrite. Keywords: Flotation, tailing, pyrite, cleaner production

Jan 1, 2020

By A. M. El Shafey, Ahmed W. Hussein, Ibrahim M. Gaafar, Mona M. Fawzy, Mohamed Diab, Mohamed S. Abu El Ghar

The Quaternary stream sediments of the Diit area, southern Red Sea coast, Egypt, were mineralogically studied for their content of economic heavy minerals. The study area covered approximately 450 km2 and included three main parts: Wadi and Delta Diit, as well as Diit lens. The mineralogical investigation revealed that these sediments contain considerable amounts of placer ilmenite, magnetite, zircon, sphene, apatite, garnet, and rutile. Also present, in minor or trace amounts, are uranothorite, monazite, xenotime, fergusonite, khatyrkite, and gold. The magnetic fractionation tests, supplemented with the XRD and SEM mineral analyses, indicated the presence of Fe-oxide minerals as wuestite, hematite, and maghemite accompanied with magnetite as products for hand magnet separation. Ilmenite separation was carried out using a high intensity magnetic separator at a current of 1 A, while the paramagnetic minerals (e.g., garnet, pyroxene, amphibole, epidote, monazite, xenotime, and fergusonite) were separated as magnetic fraction at a current of 3 A. The non-magnetic minerals (e.g., zircon, apatite and rutile, uranophane, uranothorite, gold, and khatyrkite) were obtained at 3 A current. On a mineralogical and geochemical basis, the present work suggests that Diit stream sediments should be considered as a potential source for Ti, Fe, Zr, Zn, and Cu after the physical upgrading processes for concentrating the minerals carrying the aforementioned economic elements.

Jan 21, 2022

By H. W. Reid

One of the outstanding features of the year was a further marked decline in the footage drilled. This is estimated at 169,000 ft., as against 218,000 ft. for the previous year, and 372,500 ft. in 1930. Owing to repair work and improved production methods, there was an increase of about 4.25 per cent in the amount of oil won, the production being estimated at 10,160,000 bbl., or an increase of 400,000 bbl. over 1931 and nearly 750,000 bbl. more than in 1930. (See Table 1.) At the end of November there were 28 rigs in operation. During the first 11 months of the year 54 new wells were started; the average depth of those completed was 2476 feet. Owing to the continued restriction of drilling programs there has been little of outstanding interest in the way of new plant or technique. The use of the acid bottle, for testing the verticality of wells while drilling, has increased considerably, and this is now in use in practically every well except the very shallowest. During the last six months of the year fairly extensive use has been made of electrical coring. The number of wells started in the Colony up to the end of November, 1932, was 1894. The average number of producing wells during the year was 789, or 41.7 per cent of the total. Of these, 214 were flowing wells, 473 pumping, 80 bailing or swabbing, and 22 were produced by air or gas-lift. Although the last category represents less than 3 per cent of the total, there has been a marked increase in the use of air or gas-lift as compared with 1931. During the year there were 16 companies engaged in producing oil, as compared with 14 in the two previous years. In addition to one small refinery which started to operate at the beginning of the year, the five existing refineries worked continuously. At the latter very little has taken place in the way of extensions, except at one in the Parry Lands—Pitch Lake—Point Fortin area, where extensive alterations and additions are in progress, including the building of a deep-water pipe-line pier. When this is completed there will be five loading terminals, all situated in the sheltered Gulf of Paria, or west, coast, capable of accommodating ocean-going tank steamers. There

Jan 1, 1933