GB/T 2007.6-1987 PDF in English
GB/T 2007.6-1987 (GB/T2007.6-1987, GBT 2007.6-1987, GBT2007.6-1987)
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| GB/T 2007.6-1987 | English | 80 |
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General rules for the sampling and sample preparation of minerals in bulk - Determination of moisture content - Heat drying method
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Standards related to (historical): GB/T 2007.6-1987
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GB/T 2007.6-1987: PDF in English (GBT 2007.6-1987) GB 2007.6-1987
GB
UDC 622-3. 543.05
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Replacing GB 2007-1980
General Rules for the Sampling and Sample
Preparation of Minerals in Bulk
Determination of Moisture Content –
Heat Drying Method
ISSUED ON. DECEMBER 15, 1987
IMPLEMENTED ON. OCTOBER 01, 1988
Issued by. National Standard Bureau
Table of Contents
1 Scope of application ... 3
2 Normative references ... 3
3 Instruments... 3
4 Sample ... 3
5 Determination ... 4
6 Calculation and result expression ... 5
Annex A Determination of Moisture Content of Sticky and Wet Ore
(Supplement) ... 7
Annex B Sprayed Water and Rain Water Correction (Supplement) ... 8
Additional information... 13
NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA
General Rules for the Sampling and Sample
Preparation of Minerals in Bulk
Determination of Moisture Content - Heat Drying Method
UDC 622-3.543.05
GB 2007.6-87
Replacing GB 2007-80
1 Scope of application
This standard applies to the determination of moisture content of ore described in GB
2007.1. However, it does not apply to some easily oxidized sulfide ore.
2 Normative references
GB 2007.1 General rules for the sampling and sample preparation of minerals in
bulk-Sampling by manual method
GB 2007.2 General rules for the sampling and sample preparation of minerals in
bulk-Manual method of sample preparation
3 Instruments
3.1 Drying plate. Stainless metal plate of which the surface is smooth and clean. It can
accommodate a specified number of samples of which the thickness of sample layer does
not exceed 31.5mm.
3.2 Drying oven. Air-blowing device that has adjustable temperature control device with
temperature error of less than ±5°C, and can make air flow inside the drying oven without
blowing away the samples.
3.3 Balance. Maximum weighing is not less than 3 000g. Sensitivity is 0.1g.
4 Sample
Take samples and prepare samples in accordance with relevant standards. For samples
that are too wet or sticky and thus hard to sift or crush or divide, samples can be pre-dried
until sample preparation is not difficult (see Annex A). Minimum mass of required aqueous
sample is shown in Table 1.
Table 1 Minimum mass of each aqueous sample
Maximum Particle Size, mm Minimum Mass, kg
22.4
10.0
5 Determination
5.1 Determination times
Conduct one-time moisture determination for each aqueous sample according to sample
preparation mode according to the test number specified in Table 2.
Table 2 Aqueous sample test number
Sample Preparation Test Number
Number of duplicate samples in
Each Delivery Lot
Each bulk sample
Each duplicate sample
Each increment
At least 1
At least 1
2~5
>6
Note. In addition to the special requirements agreed by the buyer and the seller through negotiation,
generally samples taken in each handling workday shall constitute at least one aqueous duplicate sample;
aqueous sample shall be weighed as soon as possible after it is received; long-time placement is not
allowed.
5.2 Determination procedures
Place aqueous sample into a drying plate with a known mass (m1) and pave according to
the mass specified in Table 1; control its thickness within 30mm; weigh (m2) and place into
the drying oven that has been preset to a specified temperature. Keep this temperature for
at least 2h; take out the drying plate that contains sample; immediately weigh it while it is
hot, or place into a dryer to cool to room temperature and weigh. When it is weighed while
being hot, weighing device shall adopt insulation measures to avoid heat.
Again put the drying plate that contains sample into drying oven to continue drying for 1h;
and then weigh. Repeat above procedure until it reaches a constant weight (m3), i.e. the
difference between last two weighings is less than 0.05 % of aqueous sample mass.
6 Calculation and result expression
6.1 Calculation of sample moisture
Moisture content W1 (%) of each aqueous content is calculated according to Formula (1).
It is reported to the second decimal.
1
mm
mmW ... (1)
Where,
m1 — Mass of drying place, g;
m2 — Mass of sample and plate before drying, g;
m3 — Mass of sample and plate after drying, g.
6.2 Calculation of moisture content of one lot of ore
6.2.1 When moisture content of aqueous sample from bulk sample is determined, mean
value W of moisture contents of whole lot of ore is calculated according to Formula (2);
it is reported to the first decimal;
21 WWW ... (2)
Where,
W1, W2 — Respectively referring to moisture determination results of two aqueous
samples, expressed in mass percentage.
6.2.2 When moisture content of duplicate sample is determined, calculate according to
Formula (3). Moisture content of duplicate sample is calculated to the first decimal;
moisture content W (%) of whole lot is reported to the first decimal.
k
WN
1 ... (3)
Where,
K — Number of duplicate samples;
Ni — Number of increments in i-th duplicate sample.
Wi — Moisture content of i-th duplicate sample, %;
i — 1, 2, ..., k.
6.2.3 When a lot of ore is divided into several parts with unequal mass, moisture content
of each part must be determined separately; moisture content of each part is accurate to
the second decimal in calculation; moisture content of the whole lot is reported to the first
decimal.
k
WM
1 ... (4)
Where,
K — Number of parts that whole lot of ore is divided into;
Mi — Mass of i-th portion;
Wi — Moisture content of i-th portion;
i — 1, 2, ..., k.
6.2.4 When each increment is used to measure moisture, moisture content W (%) of
whole lot of ore is calculated according to Formula (5). The result is reported to the first
decimal.
i
1 ... (5)
Where,
n — Number of increments.
Wi — Moisture content of i-th increment, %.
Annex A
Determination of Moisture Content of Sticky and Wet Ore
(Supplement)
When it is difficult to crush and divide the sample because the sample is too wet or sticky,
sample shall be pre-dried. In this case, determine the moisture content of whole lot of ore
according to the method specified in A1 to A3; and then calculate total moisture content
according to clause A4 to clause A7.
A1 Mass of sample weighed is accurate to 0.05% of sample mass.
A2 Pave the sample and place it into drying apparatus that is set to a specified temperature
or in air; dry to approximate equilibrium between ore moisture and air humidity; do not lose
fine powder during the drying process.
A3 After pre-drying of ore, weigh sample’s mass again; calculate pre-drying moisture
content Wp (%) of sample according to Formula (A1).
21
mmWp ... (A.1)
Where,
m1 — Mass of sample before pre-drying, kg;
m2 — Mass of sample after pre-drying, kg.
A4 Prepare samples for determination of heat drying moisture from pre-dried samples in
accordance with relevant standard.
A5 Determine loss on drying of sample according to clause 5.2; and calculate moisture
content Wd (%) of sample after pre-drying according to Formula 6.1.
A6 Calculate total moisture content Wpd (%) of sample according to Formula (A2).
ppd W
WW 100
100 ... (A.2)
Where,
Wd — Moisture content of sample after pre-drying, %.
A7 Calculate moisture content (%) of the whole lot according to clause 6.2.
Annex B
Sprayed Water and Rain Water Correction
(Supplement)
In order to prevent environmental pollution, it should spray water to ore during the handling
process, so as to suppress the dust flying. In this case, it is necessary to correct the mass
of sprayed water in moisture content of whole lot of ore according to the method specified
in this Annex.
This Annex also describes moisture content correction method of a lot of ore that contains
rainwater.
B1 Sprayed water correction
B1.1 Sprayed water
It refers to the water sprayed to cabin or the water sprayed to sampling points during ship
loading as well as the water sprayed to cabin at the time of shipment and (or) the water
sprayed to ore after aqueous sample is taken.
B1.2 Determination of sprayed water
Sprayed water may be determined through flow meter of which the degree of accuracy is
±5 %; multiply the volume measured by the density of sprayed water; then convert into
mass Mi, expressed in tons.
B1.3 Mass of delivery lot
Mass M4 of delivery lot refers to the mass measured through water gauge or other means,
expressed in tons.
B1.4 Calculation method of moisture content when aqueous sample is taken during ship
unloading.
Moisture content Ws (%) of a lot of ore for correction of sprayed water is calculated
according to Formula (B1). The result is reported to the first decimal.
MWWWs
3)100( ... (B.1)
Where,
W — Mean value of moisture contents (%) of samples that contain sprayed water,
calculated to the second decimal;
M3 — Mass of sprayed water, t;
M4 — Mass of whole...
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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