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By W. A. Bates, R. J. Miller

Although cresylic acids have been standard frothers in flotation for many years, there has been little discussion of their nature in the metallurgical literature. Aside from references in the patent literature, the paper by Landolt, Hill, and Lowyl in 1930, which resented a study of the frothing and collecting properties of some of the constituents of crude cresylic acids, represents the only contribution of this type. The close froth control required in the delicate selective separations of present-day flotation operations have required the flotation metallurgist to choose his frothers with care, and have caused him to require of the manufacturer a closely controlled, uniform product. A background of knowledge of the chemical composition and physical and chemical properties of the frothers, by which their action may be correlated, should aid in selecting frothers for particular flotation requirements. Further, the recent almost complete replacement in flotation of coal-tar cresylic acids by those derived from petroleum makes it especially desirable to review the flotation behavior of the acids from the old and the new sources. In view of these facts the Milling Methods Committee of the A.I.M.E. suggested to the Oronite Chemical Co. of San Francisco the preparation of a paper on the subject, and this paper has accordingly been prepared as a contribution by the California Research Corporation, the research affiliate of the Oronite Chemical Co. The discussion is from the following aspects: (I) constitution and properties; (2) sources; (3) comparison of coal-tar and petroleum cresylic acids; (4) characteristics as frothers, with particular reference to the effect of the substitution of petroleum acids for coal-tar acids. Constitution and Properties Cresylic acids are commonly regarded as mixtures of orthocresol, metacresol and paracresol. This was, indeed, the former meaning of the term, but in recent years it has been loosely applied to any mixture of alkyl phenols boiling above 190°C.; that is, excluding only phenol itself. This means that cresylic acids, as they are known today, may consist of mixtures, not only of the three isomeric cresols, but of six xylenols and of a variety of higher boiling homologues. Generically the constituents of cresylic acids are alkyl phenols, and they are often so designated in the literature to avoid the more indefinite term, "cresylic acids." They form an homologous series starting with phenol, which has the familiar benzene ring, with an hydroxyl group in place of one of the hydrogen atoms. The series of alkyl phenols is formed by the substitution of alkyl side chains, such as methyl, ethyl, propyl, butyl, etc., for hydrogen atoms of the benzene ring of phenol. Some

Jan 1, 1947

By R. J. Miller, W. A. Bates

Although cresylic acids have been standard frothers in flotation for many years, there has been little discussion of their nature in the metallurgical literature. Aside from references in the patent literature, the paper by Landolt, Hill, and Lowyl in 1930, which resented a study of the frothing and collecting properties of some of the constituents of crude cresylic acids, represents the only contribution of this type. The close froth control required in the delicate selective separations of present-day flotation operations have required the flotation metallurgist to choose his frothers with care, and have caused him to require of the manufacturer a closely controlled, uniform product. A background of knowledge of the chemical composition and physical and chemical properties of the frothers, by which their action may be correlated, should aid in selecting frothers for particular flotation requirements. Further, the recent almost complete replacement in flotation of coal-tar cresylic acids by those derived from petroleum makes it especially desirable to review the flotation behavior of the acids from the old and the new sources. In view of these facts the Milling Methods Committee of the A.I.M.E. suggested to the Oronite Chemical Co. of San Francisco the preparation of a paper on the subject, and this paper has accordingly been prepared as a contribution by the California Research Corporation, the research affiliate of the Oronite Chemical Co. The discussion is from the following aspects: (I) constitution and properties; (2) sources; (3) comparison of coal-tar and petroleum cresylic acids; (4) characteristics as frothers, with particular reference to the effect of the substitution of petroleum acids for coal-tar acids. Constitution and Properties Cresylic acids are commonly regarded as mixtures of orthocresol, metacresol and paracresol. This was, indeed, the former meaning of the term, but in recent years it has been loosely applied to any mixture of alkyl phenols boiling above 190°C.; that is, excluding only phenol itself. This means that cresylic acids, as they are known today, may consist of mixtures, not only of the three isomeric cresols, but of six xylenols and of a variety of higher boiling homologues. Generically the constituents of cresylic acids are alkyl phenols, and they are often so designated in the literature to avoid the more indefinite term, "cresylic acids." They form an homologous series starting with phenol, which has the familiar benzene ring, with an hydroxyl group in place of one of the hydrogen atoms. The series of alkyl phenols is formed by the substitution of alkyl side chains, such as methyl, ethyl, propyl, butyl, etc., for hydrogen atoms of the benzene ring of phenol. Some

Jan 1, 1947

By P. Carlone, A. Astarita, F. Rubino

Cold gas dynamic spray is an innovative technology allowing the deposition of thin metallic layers on a bulk or sheet substrate. Titanium on aluminum deposition is very attractive to the aeronautic industry, due to the enhanced corrosion resistance and wear properties of titanium coating as well as its improved compatibility with CFRP, preserving the reduced cost of aluminum substrate. One main drawback, however, is related to the micro-porosity of the deposed layer, negatively affecting the corrosion barrier performance. In this paper, the effect of selective laser post-treatment on pure grade 2 titanium coatings on AA2020-T3 sheets was experimentally and numerically investigated. Morphological features, microstructure and chemical composition of the treated zone were assessed by means of optical microscopy, scanning electron microscopy and energy dispersive X-ray spectrometry. Microhardness measurements were also carried out to evaluate the mechanical properties of the treated coating. A numerical model of the laser treatment, based on a finite volume scheme, was implemented and solved to simulate the process and discuss the experimental outcomes. Obtained results highlighted the key role played by heat input and dimensional features on the effectiveness of the treatment.

Jan 1, 2015

By R. J. Miller, W. A. Bates

ALTHOUGH cresylic acids have been standard frothers in flotation for many years, there has been little discussion of their nature in the metallurgical literature. Aside from references in the patent literature, the paper by Landolt, Hill, and Lowy1 in 1930, which presented a study of the frothing and collecting properties of some of the constituents of crude cresylic acids, represents the only contribution of this type. The close froth control required in the delicate selective separations of present-day flotation operations have required the flotation metallurgist to choose his frothers with care, and have caused him to require of the manufacturer a closely controlled, uniform product. A background of knowledge of the chemical composition and physical and chemical properties of the frothers, by which their action may be correlated, should aid in selecting frothers for particular flotation requirements. Further, the recent almost complete replacement in flotation of coal-tar cresylic acids by those derived from petroleum makes it especially desirable to review the flotation behavior of the acids from the old and the new sources. In view of these facts the Milling Methods Committee of the A.I.M.E. suggested to the Oronite Chemical Co. of San Francisco the preparation of a paper on the subject, and this paper has accordingly been prepared as a contribution by the California Research Corporation, the research affiliate of the Oronite Chemical Co. The discussion is from the following aspects: (I) constitution and properties; (2) sources; (3) comparison of coal-tar and petroleum cresylic acids ; (4) characteristics as frothers, with particular reference to the effect of the substitution of petroleum acids for coal-tar acids. CONSTITUTION AND PROPERTIES Cresylic acids are commonly regarded as mixtures of orthocresol, metacresol and paracresol. This was, indeed, the former meaning of the term, but in recent years it has been loosely applied to any mixture of alkyl phenols boiling above 190°C.; that is, excluding only phenol itself. This means that cresylic acids, as they are known today, may consist of mixtures, not only of the three isomeric cresols, but of six xylenols and of a variety of higher boiling homologues. Generically the constituents of cresylic acids are alkyl phenols, and they are often so designated in the literature to avoid the more indefinite term, "cresylic acids." They form an homologous series starting with phenol, which has the familiar benzene ring, with an hydroxyl group in place of one of the hydrogen atoms. The series of alkyl phenols is formed by the substitution of alkyl side chains, such as methyl, ethyl, propyl, butyl, etc., for hydrogen

Jan 1, 1946

By A. V. Rasskazova

"The oxidized and mixed ores are processed by heap leaching. Primary ores with high gold content are floated. In recent years mining of primary ores with the low gold content (up to 4 ppm) has increased. Extraction of gold from these ores by floatation is technologically ineffective. Gravity concentration is ineffective for fine gold particles because of their floatability. The research objective was assessment of the viability of processing gold-bearing ore with combined gravitational and hydrometallurgical methods and testing of recovery of metals from a gold-copper oxidized ore chloride-hypochlorite leaching solution. The advantage of chloride-hypochlorite lixiviant is the low cost of reagents which is produced by the electrochemical synthesis of NaCl solution with the addition of HCl. The adsorption of chlorine compounds by a mineral matrix and its ability to oxidize the refractory ore components and allows for the application of chloride-hypochlorite systems for gold recovery for both oxidized and primary ores. The complexity and problem in using a gold–chloride system is the strong adsorption of gold–chloride complexes onto mineral surfaces, such as goethite, quartz, and alumina. In preliminary testing, gold recovery from gravity circuit gold bearing concentrates processed by agitation leaching in chloride-hypochlorite solution, gold recovery has reached up 82% after 4 hours of leaching. Chloride-hypochlorite leaching of copper-gold oxidized ore with preliminary processing by sulfuric acid provided for 94 % gold recovery to solution. Understanding of ecological hazard of cyanides is the motive power of researches in the field of search non-cyanic chemistries to provide for technologically and economically effective solvents of gold. Soluble compounds of chlorine with a suitable oxidizer are one of the alternatives to cyanides. Basic researches of gold extraction by chloride-hypochlorite solution have shown high rates of gold recovery.INTRODUCTION Because of the continued and growing environmental concern for the use of cyanide for gold processing, interest for the use of non-cyanide lixiviants, especially with halides has renewed recently (Tran et al., 2001; Ferron et al., 2003; Bhaghalha, 2007). Leaching solutions based on halides (chloride, bromide and iodide) are viable alternative to cyanide (Kwang et al., 2008). The major disadvantage of the chlorine–chloride system is the high reactivity of chlorine in reaction with sulfide and gangue carbonate minerals. It is believed that only high grade materials may be treated by chlorine–chloride systems economically (Baghalha, 2007). Another important problem of the application of gold–chloride complex is that it tends to be rather unstable and may re-precipitate upon contact with a reductant, such as sulfidic minerals of ore. It is well known that Au(III)–chloride hydrolysis species are strongly adsorbed by goethite, quartz, and alumina (Machfsky et al., 1991). To minimize adsorption of gold–chloro complexes, it works best to minimize the adsorption time."

Jan 1, 2018

By C. E. Johnson, R. L. Bauer, E. M. Johnson

In industry, the strength of a blasting cap is often equated to the type of explosive it can detonate. Comparable cap strength is becoming less important as nearly all caps manufactured today can initiate high explosives, such as primasheet, with ease. Previous studies were conducted to assess the quantity of energy released by various detonators into the directional propulsion of the detonator’s casing. However, the question of how much of this propulsion energy is needed to initiate an explosive remains unanswered. This study will assess the fragmentation size and velocity needed to initiate a high explosive when they are not in direct contact. For this study, primasheet was used as the main charge as it is relatively insensitive and can be situated in different positions relative to the detonator. Electric, non-electric and electronic detonators were used to evaluate initiation potential. The primasheet is observed in response to being in contact with a detonator, and not in contact with the detonator at various distances and angles. This allowed the quantity of energy transferred into the primasheet to be observed and for the initiation of the sheet to be recorded using high-speed video. This study will report the energy necessary to initiate the primasheet at various distances and angles from the charge from a number of widely used, commercial, hot wire blasting caps.

Feb 6, 2023

By Charles Baskerville

Shales containing "kerogen," or bituminous matter, which on destructive distillation yield oily and tarry matters resembling petroleum are here designated as oil-shales. They differ from oil-bearing shales from which petroleum may be obtained by so-called mechanical means. The educts obtained by the destructive distillation resemble some or all the varieties of petroleum, depending on the character of the shale and the mode of treatment. Some shale oils have a paraffin base, some an asphaltic base, or a combination; some run high in sulfur compounds. The methods of refining and cracking, therefore, are essentially the same as are used in refining petroleums. In 1860, in this country, over fifty companies were successfully distilling various natural bituminous materials for the production of " coal oil," used for illuminating purposes. The discovery of petroleum and the failure of these companies to save and utilize the valuable byproduct, ammonia, brought about their inevitable doom. Prior to that time, more or less successful efforts were made to produce from the shales of Scotland oils for illuminating and heating purposes. Competition of native petroleum from the United States early eliminated some of these companies and with the entrance of oil from the Russian and other fields into the world's markets, the Scottish oil-shale industry underwent serious and trying experiences until, in 1916, only four (Scottish) were paying concerns. These survived only through energy and the application of skill in saving valuable byproducts. A few companies have successfully operated in France and New Zealand. The Canadian Government showed active interest in the New Brunswick shales, which exist in quantity and are more valuable than the Scottish shales. The retarded development of that valuable asset of the Province of New Brunswick was most unfortunate, especially when the product was so much needed in the prosecution of the war. The economic success of a shale-oil industry depends on the following factors:

Jan 1, 1921

By Samyguin VD, Filippov LO

The aim of this paper is to emphasise the importance of knowing of the rate of the elementary flotation acts (EFA) - attachment and detachment. By studying the simplest linear model notion of the column flotation, the results of the nonlinear simulaton of flotation separation in the column with lengthwise upward mixing show two principal different types of separative mass-transfer in the column. The first is, the case of a small EFA intensity, almost without the detachment. The second is, the case of a big EFA rate, when the process is close to a local attachment-detachment equilibrium. There is also an attempt to estimate the EFA rate for three different kinds of quartz particles, floated by cation collector in the laboratory column apparatus.

Jan 1, 1993

By Robert Fernie

Demographics and Infrastructure demands have led to a significant increase in construction of: deep basements for buildings and, trough structures for Highway and Rail/Metro. Concrete embedded walls used for temporary works can be incorporated into permanent works and because of this (and geological conditions) tend to be favoured in UK. This paper considers British practice in the provision of diaphragm (slurry) walls secant (true and pseudo) piled walls contiguous piled walls Plant utilisation, construction techniques, reinforcement placement, connections, propping, water tightness, tolerances, general UK practices and their relation to design practices are discussed. [ ]

Jan 1, 2000

By R. H. Winn

A method for the selection of the most suitable corrosion inhibitor for a particular system is given. The method involves the evaluation of surface passivity by means of copper ion displacement after the metal surface has been subjected to the corrosive atmosphere. The application of the method to the selection of suitable inhibitors for use in producing wells is described. Correlation with recognized laboratory tests has beet1 found to be good within the limitations of the test. The use of the test to evaluate inhibitor persistencc is described. INTRODUCTION Corrosion as it is associated with the industry shows wide variations in its qualitative as well as its quantitative aspects. This complicates the work of the corrosion engineer. In the past few years the efforts of the corrosion engineer have been further taxed by the large numbers of products being marketed as corrosion inhibitors by various manufacturers. These products are submitted to him together with a limited amount of data to support their use as inhibitors. The data are usually authentic and reliable yet all too often when these products are applied to an actual corrosive system the results are disappointing due to the ineffectiveness of the inhibitor and the corrosive system. The corrosion engineer must select a comparatively limited number of inhibitors for field trial from the large number available. The selection is usually made on the basis of a standardized laboratory test such as that adopted by the National Association of Corrosion Engineers or by field experience in an area; however, testing of this type is discouraging on large numbers of compounds, particularly in view of the specificity of environment. It has been an object of this work to devise a method which will allow the corrosion engineer to select the best inhibitor for a specific environment under field conditions. The test would of necessity be rapid and inexpensive. It would preferably eliminate the need for expensive and delicate instruments. STATEMENT OF THEORY The test as developed makes use of the fact that metal ions will be displaced from solution by metals having a more positive electrode potential. Thus, if an active iron surface is exposed to a solution of a copper salt, free copper will plate spontaneously on the iron surface as it is displaced from the salt solution by iron ions. If the iron surface is passified, as by coating with an insulating-type organic corrosion inhibitor, it is no longer capable of displacing the copper ions due to its own limited ionization. The result will be a change in the amount of copper plated upon exposure to a neutral copper salt solution. In practice it has been found possible to measure the magnitude of the alteration of the cell potential by determining the copper deposited on a standard iron surface under controlled conditions. This means that, as the film builds up, the resulting shift in the electrode potential tends to cause the iron surface to act more like a noble metal, resulting in a reduction in the cell potential to a point that copper will no longer plate spontaneously. Obviously, the salts of other metals such as silver, gold or platinum might be used for this operation; however, copper was selected because of the color difference of the plate, the comparatively low cost of copper salts and the ease of evaluation of the plated copper. Furthermore, its high cell potential provides a substantial driving energy. The determination of the copper is readily done colorimetrically by dissolving it in 5 per cent ammonium hydroxide solution containing 2 per cent potassium per-sulfate. The blue color of the copper ammonic complex ion so developed may be compared with standards prepared by dissolving known quantities of copper powder in the same reagent. In routine screening it is seldom desirable to determine the amount of copper plated. It is usually more important to determine the concentration of inhibitor required to prevent the plating of copper.

By A. J. W. Law

"This paper deals with the organization of the central office technical areas and the role played during the feasibility studies, construction and operating phases of Les Mines Selbaie.HistoryThe Engineering Department was originally formed as a part of the Exploration Department, to examine the feasibility of advanced exploration prospects being brought to the company. In 1968, with the discovery of the South Bay property in northwestern Ontario, the department became part of a Mining Division and was expanded, so that it could provide more advanced mine feasibility studies, control of construction engineering and procurement and initial mine design. As is generally the case, the mine design function was handled with in-house capability, while plant, mill and const ruction functions used outside consultants.The 1974 discovery of the Selbaie deposits, started a period o f growth in the capabilities o f the department. The complex nature of these deposits, required that skills were added in the mining, metallurgical and plant areas. During the early feasibility study period these skills were provided by the engineering company of the parent group, but when it was realized that production from the deposits was likely, permanent staff was added."

Jan 1, 1990

No. 526.-At liberty about Mar. 1, 1919. Just returned from France, a Captain of Engineers. Member A. I. M. E., A. I. E. E., 35 years old, technical education. Last six years of civil life as electrical engineer, master mechanic and superintendent of construction with large mining company. Salary expected, $3600 per year. No. 535.-Member, 'mining engineer, technical graduate, age 34 years, experience as engineer for coal companies. Three and one-half years with one company and five years with another. Have good recommendations. Recently honorably discharged, First Lieutenant, U. S. Army. Desires position, preferably in West. Salary last received, $175 per month. No. 555.-Metallurgical engineer having 18 years' experience in positions from chemist to manager, specializing in the smelting of copper, gold and silver ores, and now returning to the U. S. Available about May 15. No. 556.-Manager or superintendent, member, technical graduate, age 44, married, desires position. Good references, 18 years' experience in positions of responsibility and administration. Familiar with development, mining, milling, operation, construction and management. Available on short notice. , No. 557.-Member, technical education, married, age 30. Five. years' experience in construction work, four years superintendent of mining and milling operations. Looking for wider experience. Free Apr. 1.

Jan 4, 1919

By J. M. Wempen

Booster fans, large underground fans, can increase the volumetric efficiency of ventilation systems by helping to balance the pressure and quantity distribution throughout a mine, reducing leakage and reducing the total power requirement. However, in ventilation systems that use booster fans there is a potential for system recirculation, the leakage of return air to intake air, and also for localized recirculation near the fan through the bulkhead and airlock doors. Air that is recirculated locally decreases the system efficiency because the quantity of air flow through the fan increases without increasing the airflow throughout the system. To understand the detailed flow characteristics of a ventilation system with a booster fan, two-dimensional computational fluid dynamics (CFD) models were developed using the software Ansys-FLUENT. Though two-dimensional models do not represent the full complexity of the flow dynamics, they do provide a good representation of the flow characteristics and they allow for a qualitative analysis of how the flow dynamics are affected by the system characteristics. The CFD models were used to evaluate how the number of booster fans, the booster fan placement, the location and geometry of the fan installation and the construction of the airlock system affect the flow characteristics and the localized efficiency of the ventilation system.

Feb 27, 2013

By D. Altizer, E. Thompson, K. F. Unrug

Because of frequent sudden changes in the geologic composition of strata, the extrapolation of rock properties obtained from core samples to the surrounding areas can cause problems. To address this issue, a method of rapid strength testing in situ using a borehole penetrometer is being developed. This method, as opposed to conventional laboratory testing, does not require rock samples to be retrieved and handled/machined before testing. Rock strengths are determined di¬rectly on the drill-hole wall. The latest development is a borehole penetrometer that requires only a 38.1-mm- (1.5-in.-) diam hole. The small diameter of the penetrometer body allows for the drilling of test holes with production mine equipment such as a roof bolter. The new penetrometer allows for the possibility of a broad application in coal mines, as well as in hard rock mines and tunneling. The principles of the apparatus are described and are illustrated with examples of its applications.

Jan 1, 2002

By Luísa Maria Abrantes

Environmental control is becoming more and more stringent. As conventional processes for zinc production are pollutant routes, alternative methods have become an important subject of research. In this regard, the leaching processes have aroused a considerable interest, namely the electrochemically induced approach. The behaviour of zinc concentrate ore in the leaching processesses is influenced by several parameters. Chloride concentration and leaching solution pH, time and temperature of reaction were studied in order to evaluate their influence on the zinc recovery. The efficiency of the leaching process for zinc extraction is performed by factorial design. The experiments were carried out by 23 and 22 factorial designs of the factors. Results show that all factors, except for the time of reaction have a significant influence on the optimisation process, within each experimental region.

Jan 1, 2001

FREQUENTLY the Survey Department is caIled upon to estimate the quantity of material in various dumps, dams piles, etc... and in the carrying out of this work various methods may be employed.The method used will vary according to the particular case in hand, and factors such as accessibility of the top of the dump, steepness of its sides, height, and the condition of the material to be estimated. A certain amount of "give and take" must be adopted in the treatment of small local cavities and mounds.In all cases it is desirable that the surveys made should be tied on to the lease surveys for the purpose of location, and that all levels should be reduced to the mine datum. It is also desirable to obtain levels of the original surface before deposition of the material to be estimated. If these have not been obtained beforehand, levels and transfers round the top will be the next best. If space is availabIe, flat surface is chosen as a site for the dump, etc. This is of the utmost importance in those cases where the material will have to be...

Jan 1, 1925

By D. R. Brox, J. Levell

The Montana Tunnels Mine was mined out to a depth of 900 feet at the end of 1999. The first signs of instability were recognized in 1996 along the upper slope area of the northwest sector when the pit was mined out to a depth of approximately 500 feet. To extend the life of mining operations, it has been proposed to extend and steepen the northwest highwall to a depth of 1000 feet. Slope stability analyses were carried out using the UDEC software program to assess the stability and deformation of the proposed highwall design. Back analysis of an instability in 1997 along the upper slope section and highwall deformation to date has indicated reasonable agreement with the observed mode of failure and displacement monitoring results. The results of detailed analyses of the proposed highwall design have indicated very limited additional deformation, further development of tension cracks is unlikely and large-scale instability is not expected to occur. A total of 40% of additional mining has been completed and ongoing displacement monitoring to date has confirmed very limited additional movement and no further tension crack development.

Jan 1, 2001

By Charles E. Packard

Many coal producers have been faced recently with the problem of arranging their production facilities to accommodate recent trends in the transportation of their product. Each operator is normally faced with a different problem requiring a system to meet his specific needs. It may be that he would be required to load a seven or eight thousand ton integral train each day which would naturally call for a large storage pile, high loading rate, accomplished in a minimum of time On the other hand, it may be that he is faced with furnishing coal to make up one-half of a unit train that is to be assembled twice a week. Whether the problem is large or small, many considerations must be given to each specific problem to be certain that the proper scheme is applied. The operator actually has several choices as to what type of storage and loading facilities he may consider. The storage pile, for instance, may be open type, conical in shape, kidney-shaped, or long and wedge-shaped. It may also be enclosed by steel or concrete

Jan 8, 1964

By Gary F. Meenan

Continuous pi lot scale dewatering tests compared the performance of the vacuum disc filter with that of the screen bowl and the solid bowl centrifuges. The test results allow the a priori prediction of plant product moisture based on the feed particle size. This information is useful for selecting the best dewatering device for a given size material and for optimizing the dewatering performance of existing plant installations. Quantitative information was gathered on the ability of filter aids to improve the filtration rate of fine coal slurries. A polymeric flocculant and oil were added to the disc filter feed material at various dosage levels. Both filter aids increased the disc filter output. For the coal tested, the flocculant filter aid achieved higher filtration rates at a lower cost.

Jan 1, 1988

By J. S. Vanick

An extremely hard, tough, and strong, white or chilled cast iron has been applied for the past several years to industrial and mining services in which its unusual properties have been confirmed by its ability to deliver in many instances much better performance than plain chilled iron, or other wear-resistant materials. It is being produced regularly by alloying a good base composition of chilled or white cast iron with essentially 4 to 6 per cent of nickel and 1 to 2.5 per cent of chromium. Such a material can attain a hardness exceeding 600 to 750 Brinell as against 380 to 530 for corresponding grades of plain chilled iron. The strength is approximately doubled and the toughness significantly increased. These properties make it especially useful for many applications requiring a high hardness for resistance to wear, abrasion, attrition, deformation; to some extent to high compressive loading and to a lesser but important degree to corrosive action. A wide variety of commercial castings is being successfully produced from this iron, ranging in size from the small grain-grinding plates or burrs through medium-sized castings such as sand pumps up to large, heavy castings such as rolls for metal rolling or cement grinding. The composition of this white cast iron may be roughly bracketed within the range shown in Table 1.

Jan 1, 1933