NSF-1 Stone Powder Content Tester (Methylene blue method)

Product details:

  1. Scope of application

This instrument is a special instrument designed according to T0349-2005 of Ministry of transportation, “fine aggregate methylene blue test”. Advanced frequency modulation, numerical control technology are adopted to improve the test accuracy and speed. It is a necessary instrument for the laboratory. This method is suitable for determining whether there are expansive clay minerals in fine aggregate and its content, so as to evaluate the cleanliness of aggregates, expressed as methylene blue value MBV. This method is suitable for fine aggregate less than 2.36mm or less than 0.15mm, and also can be used for quality inspection of mineral powder. If the passing rate of 0.075mm in fine aggregate is less than 3%, it can be regarded as qualified without this test.

  1. Technical parameters

Power supply voltage: 220V        Maximum speed: 600 rpm /±10 rpm

Minimum speed: 400 rpm±10rpm  Impeller diameter: 75mm±10 mm

Number of impellers: 3 beakers     Volume: 1000ml

  1. Operation method

The main machine of the instrument uses a constant speed powerful electric mixer, adopts advanced high-speed microcomputer chip to sample and control the motor speed, which is stable in speed, and the display is intuitive and clear. It can set the speed at any time by buttons, and also has the function of timing and data saving. And use double digital display, very intuitive and clear. The longest time is 999. Once the parameter is set, it can be saved for a long time.

For example, set up electric mixer to stop working after 500 times per minute for 30 minutes.

  1. Close the power switch, and the left is displayed as the original speed value(The last running speed) is displayed as the original timing value on the right;
  2. Press the fast and slow key to set the speed to 500;
  3. Press the ▲ or ▼ key to set the timing to 30 minuteS(setting 0 points indicates the non timing normally open state);
  4. Press the start key to start, the machine can start slowly until 500 rpm, and then the timer starts. Itwill stop after 30 minutes of stable operation and alarm for 10 seconds , indicating that the timing operation is completed;
  5. Press stop to stop operation at any time;
  6. Green is the start lamp, red is the stop lamp; If the corresponding indicator light is on, the instrument is in corresponding state.
  7. Test procedure
  8. Preparation of the he standard methylene blue solution (910.0 g / L ± 0.1 g / L standard concentration) ;

(1) The moisture content w in methylene blue was determined. Weigh about 5g methylene blue powder, record the mass MH, accurate to 0.01g. Dry it to constant weight at 100 ℃± 5 ℃ (some methylene blue powder will deteriorate when the temperature exceeds 105 ℃), cool it in a dryer, then weigh it, record the mass mg, accurate to 0.01g. The water content w of methylene blue is calculated according to the formula (t0349-1)

w = (mh-Mg)/mg × one hundred

Where: MH – mass of methylene blue powder (g);

Mg – mass of methylene blue after drying (g).

(2) Take methylene blue powder (100 + W) (10g ± 0.01g) / 100 (i.e. the mass of methylene blue dry powder is 10g), accurate to 0.01g.

(3) Heat the beaker containing about 600 ml clean water, and the water temperature shall not exceed 40 ℃.

(4) Add methylene blue powder while stirring, stirring for 45 min until all methylene blue powder is dissolved, and then cooling to 20 ℃.

(5) Pour the solution into a 1L volumetric flask, wash the beaker with clean water, etc., so that all methylene blue solutions are transferred into the volumetric flask. The temperature of the volumetric flask and solution should be kept at 20 ℃± 1 ℃, and add clean water to the 1L scale of the volumetric flask.

(6) Shake the volumetric flask to ensure that the methylene blue powder is completely dissolved. Transfer the standard solution into the dark storage bottle, and the shelf life of methylene blue standard solution should not exceed 28 days. The prepared solution should be marked with preparation date and expiration date, and stored away from light.

  1. Preparation of fine aggregate suspension

(1) Take a representative sample, cut it down to about 400g, and dry it in an oven at 105℃±5℃ to a constant weight. After cooling to room temperature, sieve out particles larger than 2.36mm and divide it into two parts for later use.

(2) Weigh 200g of sample to the nearest 0.1g. Pour the sample into a beaker containing 500 mL ± 5 mL of clean water, adjust the stirrer speed to 600 min, and the stirrer impeller is about 10 mm away from the bottom of the beaker. Stir for 5 minutes to form a suspension. Use a pipette to accurately add 5 mL of methylene blue solution, and then keep stirring at 400r/min±40r/min until the end of the test.

  1. Determination of the amount of methylene blue adsorption

(1) Place the filter paper overhead on the top of the open beaker so that it does not come into contact with any other objects.

(2) After adding the methylene blue solution to the fine aggregate suspension and stirring at 400r/min±40r/min for 1 min, perform the first color halo test on the filter paper. That is, use a glass rod to dip a drop of suspended liquid on the filter paper. The droplet forms a ring on the filter paper with aggregate sediment in the middle. The amount of solution should be such that the diameter of the sediment is between 8mm~12mm. Surrounded by a colorless water ring. The test becomes positive when a light blue halo with a width of about 1mm is radiated from the periphery of the sediment.

(3) If the first 5 mL of methylene blue does not cause color halo around the precipitate, add 5 mL of methylene blue solution to the suspension, continue to stir for 1 min, and then dip a drop of the suspension with a glass rod. Perform the second color halo test on the filter paper. If there is still no halo around the precipitate, repeat the above steps until a stable light blue halo of about 1 mm is emitted around the precipitate.

(4) Stop adding the methylene blue solution, but continue to stir the suspension, and perform a color halo test every 1 min. If the color halo disappears within the first 4 minutes, add 5 mL of methylene blue solution; if the color halo disappears in the 5th minute, add 2 mL of methylene blue solution. In both cases, continue to stir and perform the color halo test until the color halo can last for 5 minutes.

(5) Record the total volume of the methylene blue solution added when the color halo lasts for 5 minutes to the nearest 1 mL.

  1. Rapid evaluation test of methylene blue

(1) Prepare samples and stir according to the requirements of 3. 2. (1) and 3. 2. (2).

(2) Add 30 mL of methylene blue solution to the beaker at one time, keep stirring at 400r/min±40r/min for 8 minutes, then stick a drop of the suspension with a glass rod, drop it on the filter paper, and observe whether there is obvious color around the precipitate gosh.

  1. Determination of the methylene blue value MBVF of the part with a particle size less than 0.15mm

Accurate the sample according to the provisions of III.1 to III.3, carry out the methylene blue test, but the sample is the part of 0~0.15mm, take 30g±0.1g.

  1. Determine the mud content or stone powder content in the fine aggregate according to the T0333 sieve washing method.


  1. Calculation
  2. The methylene blue value MBV of fine aggregate is calculated according to formula (T0349-2), accurate to 0.1.


In the formula: MBV—methylene blue value (g/kg), which means the number of grams of methylene blue consumed per kilogram of 0~2.36mm sample size;

m—the mass of the sample (g);

V—the total amount of methylene blue solution added (mL);

  1. Evaluation of methylene blue rapid test results

If there is obvious color halo around the precipitate, the methylene blue rapid test is judged to be qualified. If there is no obvious color halo around the precipitate, then the methylene blue quick test is judged to be unqualified.

  1. The methylene blue value MBVF of the part less than 0.15mm or mineral powder is calculated according to formula (0349-3), accurate to 0.1.


In the formula: MBVF——methylene blue value (g/kg), which means the number of grams of methylene blue consumed per kilogram of 0~0.15mm particle size or mineral powder sample;

m1—the mass of the sample (g);

V1—The total amount of methylene blue solution added (mL)

  1. The calculation and evaluation of the mud content or mineral powder content in the fine aggregate shall be carried out according to the method of T0333.
  2. Matters needing attention

The power supply of this instrument is 220V 50Hz. When the user’s power supply voltage exceeds 240V or is lower than 180V, a regulated power supply must be considered, otherwise it will affect the speed.

  1. random accessories

1 speed agitator 1 power cord 1 4 impellers

1 certificate, 1 insurance tube, 1 manual

  1. Bring your own accessories

1000mL beaker*1;  2mL pipette *1;  5mL

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