Standard Test Method for Laboratory Weathering of Solid Materials Using a Humidity Cell
适用范围：<p>The laboratory weathering procedure will generate data that can be used to: (<span class="italic">1</span>) determine whether a solid material will produce an acidic, alkaline, or neutral effluent, (<span class="italic">2</span>) identify solutes in the effluent that represent dissolved weathering products formed during a specified period of time, (<span class="italic">3</span>) determine the mass of solute release, and (<span class="italic">4</span>) determine the rate at which solutes are released (from the solids into the effluent) under the closely controlled conditions of the test.</p> <p>Data generated by the laboratory weathering procedure can be used to address the following objectives: (<span class="italic">1</span>) determine the variation of drainage quality as a function of compositional variations (for example, iron sulfide and calcium+magnesium carbonate contents) within individual mine-rock lithologies, (<span class="italic">2</span>) determine the amount of NP accessible in a mine-rock sample to neutralize acid and maintain drainage pH<span class=''unicode''>x2265;</span>6.0 under the conditions of the test, (<span class="italic">3</span>) estimate mine-rock weathering rates to aid in predicting the environmental behavior of mine rock, and (<span class="italic">4</span>) determine mine-rock weathering rates to aid in experimental design of site-specific kinetic tests.</p> <p>The laboratory-weathering procedure provides conditions conducive to oxidation of solid material constituents and enhances the transport of weathering reaction products contained in the resulting weekly effluent. This is accomplished by controlling the exposure of the solid material sample to such environmental parameters as reaction environment temperature and application rate of water and oxygen.</p> <p>Because efficient removal of reaction products is vital to track mineral dissolution rates during the procedure, laboratory leach volumes are large per unit mass of rock to promote the rinsing of weathering-reaction products from the mine-rock sample. A comparison of laboratory kinetic tests with field tests has shown that more reaction products from mineral dissolution are consistently released per unit weight and unit time in laboratory weathering tests <span class="bold">(9)</span>. For example, sulfate release rates observed in laboratory tests of metal-mine rock have been reported to be 3 to 8 times those for small-scale field test piles of Duluth Complex rock <span class="bold">(10)</span>, and from 2 to 20 times those for small-scale field test piles of Archean greenstone rock <span class="bold">(11)</span>. A greater increase is anticipated when laboratory rates are compared with field rates measured from operational waste-rock piles.</p> <p>Fundamental assumptions governing Options A and B of the procedure:</p><p id="s00002">1.1 This kinetic test method covers a laboratory weathering procedure that (<span class="italic">1</span>) enhances reaction-product transport in the aqueous leach of a solid material sample of specified mass, and (<span class="italic">2</span>) measures rates of weathering-product mass release. Soluble weathering products are mobilized by a fixed-volume aqueous leach that is performed and collected weekly. Leachate samples are analyzed for pH, alkalinity/acidity, specific conductance, sulfate, and other selected analytes.</p> <p id="s00003">1.1.1 This test method is intended for use to meet kinetic testing regulatory requirements for mining waste rock and ores sized to pass a 6.3-mm (0.25-in.) Tyler screen.</p> <p id="s00004">1.1.2 Interlaboratory testing of this method has been confined to mine waste rock. Application of this test method to metallurgical-processing waste (for example, mill tailings) is outside the scope of the test method.</p> <p id="s00005">1.2 This test method is a modification of a laboratory weathering procedure developed ori......
中标分类号： Q04 - 建材 - 基础标准与通用方法
ICS分类号： 19.040 - 试验 - 环境试验
标准组织： ASTM - 美国材料与试验协会标准
英文关键词： chemical weathering humidity cell laboratory weathering mill tailings ore oxidation solid material waste rock Accelerated weathering Humidity cells Metal-mine waste-rock weathering Oxidation testing Rock materials/properties/analysis Solid phase materials Waste materials/processing/analysis
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