ASTM WK46553

    Revision of C123 / C123M - 12 Standard Test Method for Lightweight Particles in Aggregate

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    Active Standard: C123 / C123M - 12

    Developed by Subcommittee: C09.20 | Committee C09 | Contact Staff Manager



    WK46553

    1. Rationale

    Currently, C123 cites the use of specific organic and inorganic liquids for use in aggregate particle separation by heavy liquid. The proposed change is to add information Section 6.1.5 and Note 3 concerning the use of other inorganic heavy liquids, such as lithium metatungstate (2.95) and lithium heteropolythungstate (2.85). These inorganic liquids are less hazardous and more effective than the liquids currently cited in C123. Solutions of tungstate metals provide much lower viscosities resulting in quicker and more succinct separations than that of zinc chloride or zinc bromide. The proposed change will include the following: 6.1.5 A mixture of water soluble heavy inorganic liquids proportioned to achieve desired densities. (See Note 3) Note 3 Suggested liquids (and their densities) include, but are not limited to, solutions of lithium metatungstate (2.95) and lithium heteropolytungstates (2.85). Supporting data and information regarding the health risks of inorganic liquids, such as lithium metatungstate and lithium heteropolytungstate are presented below: Solutions of water soluble lithium metatungstate and lithium heteropolytungstates are considerably less hazardous then the suggested heavy organic liquids or zinc bromide within C123. Based upon reported NFPA 704 (National Fire Protection Association) ratings in Materials Safety Data Sheets (MSDSs); the health hazard rankings of the listed organic heavy liquids and their solvents are a 3 or extreme danger. Skin exposure produces burns. Solutions of zinc bromide have also been reported to have a health hazard of 3. Solutions of water soluble lithium metatungstate and lithium heteropolytungstates are reported within their MSDSs to have a health hazard of 1 or slightly hazardous; the same rating as solutions of sodium chloride or table salt. The use of lithium tungstate salt solutions has an over 20 year history of use in palynology and sedimentary labs and the mining industry. Further, the generally lower viscosity of these solutions at 2.0 and 2.4 specific gravity, when compared to those solutions currently listed in C123, produce more succinct separations. Viscosity is typically measured in centipoise (cP). Water is 1 cP. Independent testing of the following solutions reveals the significant difference in viscosity between three types of inorganic heavy liquids: Zinc chloride2.0 spg95.6cP Zinc bromide2.4 spg25.0cP Lithium metatungstate 2.4 spg9.4 cP Lithium metatungstate2.0 spg4.1 cP


    Keywords

    aggregate; heavy liquid; lightweight particles; Coarse aggregate; Fine aggregate; Lightweight aggregate; Sieve analysis--aggregate; Sink-float method
    Citing ASTM Standards
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    Work Item Status

    Date Initiated:
    06-26-2014

    Technical Contact:
    Glenn Waite

    Item:
    002

    Ballot:
    C09.20 (14-05)

    Status:
    In Balloting