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The Recovery Of Tin And Tungsten From Various Zones Of The Van Roois Vley Deposit Including Settling And Filtration
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Book Synopsis The Recovery of Tin and Tungsten from Various Zones of the Van Roois Vley Deposit, Including Settling and Filtration by : C. F. B. Coetzee
Download or read book The Recovery of Tin and Tungsten from Various Zones of the Van Roois Vley Deposit, Including Settling and Filtration written by C. F. B. Coetzee and published by . This book was released on 1988 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Recovery of Tin and Tungsten from Various Zones of the Van Roois Vley Deposit, Including Settling and Filtration by : Christiaan Frederick Beyers Coetzee
Download or read book The Recovery of Tin and Tungsten from Various Zones of the Van Roois Vley Deposit, Including Settling and Filtration written by Christiaan Frederick Beyers Coetzee and published by . This book was released on 1983 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Recovery of Tin and Tungsten from Various Zones of the Van Roois Vley Deposit, Including Settling and Filtration by :
Download or read book The Recovery of Tin and Tungsten from Various Zones of the Van Roois Vley Deposit, Including Settling and Filtration written by and published by . This book was released on 1983 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eight samples of tin-tungsten concentrates from various zones of the Van Roois Vley deposit were tested, by what was then regarded as a standard leach, in 10 M hydrochloric acid at 95 degrees C under atmospheric pressure for 4 hours. The samples were milled to smaller than 106 um before being leached. Some of these samples were of a more refractory nature than the others, and gave poor recoveries of tungsten (one as low as 34 per cent). However, when the samples were milled to finer than 38 um, all except sample VRC-2 gave optimum recoveries. An extended leach of up to 10 hours brought the recovery from VRC-2 to 99,9 per cent. Larger composite samples (of 1,5 kg each) were leached under a pressure of 200 to 300 kPa at 120 degrees C for 5 hours. The object was to produce some design parameters with regard to leaching, settling, filtration, and precipitation of synthetic scheelite. Leaching yielded extractions of 99 per cent. Leaching under pressure caused dissolution of the calcium fluoride impurity in the concentrate and severe attack of the glass lining of the leaching vessel by the hydrofluoric acid thus formed. The overall recovery of tungsten as calcium tungstate was 98,6 per cent at a grade of 94 to 97 per cent calcium tungstate, with impurity levels well below the limits set by industry.
Book Synopsis Use of Services for Family Planning and Infertility, United States, 1982 by : Gerry E. Hendershot
Download or read book Use of Services for Family Planning and Infertility, United States, 1982 written by Gerry E. Hendershot and published by . This book was released on 1988 with total page 982 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1982 statistics on the use of family planning and infertility services presented in this report are preliminary results from Cycle III of the National Survey of Family Growth (NSFG), conducted by the National Center for Health Statistics. Data were collected through personal interviews with a multistage area probability sample of 7969 women aged 15-44. A detailed series of questions was asked to obtain relatively complete estimates of the extent and type of family planning services received. Statistics on family planning services are limited to women who were able to conceive 3 years before the interview date. Overall, 79% of currently mrried nonsterile women reported using some type of family planning service during the previous 3 years. There were no statistically significant differences between white (79%), black (75%) or Hispanic (77%) wives, or between the 2 income groups. The 1982 survey questions were more comprehensive than those of earlier cycles of the survey. The annual rate of visits for family planning services in 1982 was 1077 visits /1000 women. Teenagers had the highest annual visit rate (1581/1000) of any age group for all sources of family planning services combined. Visit rates declined sharply with age from 1447 at ages 15-24 to 479 at ages 35-44. Similar declines with age also were found in the visit rates for white and black women separately. Nevertheless, the annual visit rate for black women (1334/1000) was significantly higher than that for white women (1033). The highest overall visit rate was for black women 15-19 years of age (1867/1000). Nearly 2/3 of all family planning visits were to private medical sources. Teenagers of all races had higher family planning service visit rates to clinics than to private medical sources, as did black women age 15-24. White women age 20 and older had higher visit rates to private medical services than to clinics. Never married women had higher visit rates to clinics than currently or formerly married women. Data were also collected in 1982 on use of medical services for infertility by women who had difficulty in conceiving or carrying a pregnancy to term. About 1 million ever married women had 1 or more infertility visits in the 12 months before the interview. During the 3 years before interview, about 1.9 million women had infertility visits. For all ever married women, as well as for white and black women separately, infertility services were more likely to be secured from private medical sources than from clinics. The survey design, reliability of the estimates and the terms used are explained in the technical notes.
Book Synopsis Unrestricted Mintek Publications by :
Download or read book Unrestricted Mintek Publications written by and published by . This book was released on 1987 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts written by and published by . This book was released on 1991 with total page 948 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Government Reports Announcements & Index by :
Download or read book Government Reports Announcements & Index written by and published by . This book was released on 1988 with total page 988 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Recovery of a Concentrate of Tin and Tungsten from Ore Mined at Van Roois Vley by : Robert Nelson Guest
Download or read book The Recovery of a Concentrate of Tin and Tungsten from Ore Mined at Van Roois Vley written by Robert Nelson Guest and published by . This book was released on 1983 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Application of a Standard Leaching Procedure to Tin-tungsten Concentrates from Van Roois Vley Deposit : Cross-cut Bulk Samples by :
Download or read book The Application of a Standard Leaching Procedure to Tin-tungsten Concentrates from Van Roois Vley Deposit : Cross-cut Bulk Samples written by and published by . This book was released on 1984 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shell South Africa (Pty) Limited, Metals Division, asked Mintek to investigate the feasibility of treating tin-tungsten concentrates from different areas of Van Roois Vley deposit by a standard leaching procedure. These concentrates were derived from bulk samples that had been taken from underground exploration operations. The tests showed that, at a particle size of 100 per cent smaller than 106 um, only five samples were readily digested with 10 M hydrochloric acid and had a tungsten recovery of more than 99 per cent. Extractions of more than 94 per cent were obtained from nine samples, whereas only 90,6 per cent was recovered from one sample (cross-cut 14). The tungsten extraction improved considerably when the standard leaching procedure was employed on samples ground to 100 per cent smaller than 38 um, a recovery of more than 99 per cent being obtained from eleven samples. For the remaining four samples, the tungsten yield amounted to more than 94 per cent. If all the samples were combined, tungsten trioxide in the cassiterite residue would average 3,07 per cent from feed material with a particle size of 100 per cent smaller than 106 um, and to 1,48 per cent from a feed of 100 per cent smaller than 38 um.
Book Synopsis The Recovery of a Concentrate of Tin and Tungsten from Ore Mined at Van Roois Vley by :
Download or read book The Recovery of a Concentrate of Tin and Tungsten from Ore Mined at Van Roois Vley written by and published by . This book was released on 1983 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concentration tests using gravity separation, flotation, and magnetic separation showed that it is possible for the high-grade ore mined at Van Roois Vley to be upgraded to a concentrate containing 61 per cent Sn-WO3 at a recovery of about 80 per cent, and for the low-grade ore to be upgraded to 53 per cent Sn-WO3 at the same recovery. However, it is suggested that, under normal mining conditions and with large-scale mining equipment, less fines would be produced and this should lead to an increase in grade and recovery. Mineralogical examinations showed that intermediate fractions produced by tabling contained very few locked particles, and that the grade of the final concentrate on a full-scale plant would probably be higher than that obtained with laboratory equipment. Molybdenite could be a valuable byproduct, but flotation tests of gravity concentrates for selective recovery of the mineral gave variable results. Flotation tests for the removal of fluorspar from the final concentrate were unsuccessful.
Book Synopsis Hydrochloric Acid Leaching and Low-temperature Roasting of Tin-tungsten Concentrates from Van Roois Vley by :
Download or read book Hydrochloric Acid Leaching and Low-temperature Roasting of Tin-tungsten Concentrates from Van Roois Vley written by and published by . This book was released on 1983 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Metals Division of Shell SA (Pty) Limited carried our exploratory work on a fairly large deposit in the north-western Cape referred to as the Van Roois Vley deposit, and the Council for Mineral Technology (Mintek) produced high-grade concentrates of the tin-tungsten minerals from this area. These concentrates were treated for the separation of tin and tungsten and for the production of synthetic scheelite of a purity acceptable to industry for further processing in the manufacture of rock-drill bits. The process steps were as follows: direct leaching in 10 M hydrochloric acid at 95 degress C for 3 to 4 hours, dissolution in caustic soda of the tungstic acid formed, and precipitation of the tungsten as synthetic scheelite by the addition of calcium chloride. This process yielded 99,5 per cent recovery of tungsten into a synthetic scheelite with a tungsten content of at least 61 per cent compared with the end-user's specification of 60 per cent as a minimum. The cassiterite residue had a tin content of 60 per cent or better. Concentrates from different zones of the deposit did not all respond well to the process. A patented process (no SA 78/6478) using a low-temperature roast with sodium carbonate as the reactant was tested. This process was partially optimized and yielded over 9 per cent extraction of tungsten from the most refractory concentrates produced from various zones of the deposit. However, precipitation of the tungsten from the carbonate mother liquor presented some problems. The recovery of tungsten from carbonate liquor requires detailed investigation.
Book Synopsis Government reports annual index by :
Download or read book Government reports annual index written by and published by . This book was released on 199? with total page 1590 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Recovery of Tin, Tungsten and Other Metals from Tin Smelter Wastes by : Aaron G. Starliper
Download or read book Recovery of Tin, Tungsten and Other Metals from Tin Smelter Wastes written by Aaron G. Starliper and published by . This book was released on 1962 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Government Reports Annual Index: Keyword A-L by :
Download or read book Government Reports Annual Index: Keyword A-L written by and published by . This book was released on 1988 with total page 1600 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Application of a Standard Leaching Procedure to Tin-tungsten Concentrates from Van Roois Vley Deposit by : Monika Maria Fieberg
Download or read book The Application of a Standard Leaching Procedure to Tin-tungsten Concentrates from Van Roois Vley Deposit written by Monika Maria Fieberg and published by . This book was released on 1984 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Recovery of Tungsten from a Hydrothermally Altered Deposit by :
Download or read book Recovery of Tungsten from a Hydrothermally Altered Deposit written by and published by . This book was released on 1982 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Tungsten Deposits of Vance County, North Carolina, and Mecklenburg County, Virginia by : Gilbert H. Espenshade
Download or read book Tungsten Deposits of Vance County, North Carolina, and Mecklenburg County, Virginia written by Gilbert H. Espenshade and published by . This book was released on 1947 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
