RU2386947C2 - Method of estimating grain-size composition range of fine-dispersed particles in slime water - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method involves measurement of settling time and linear dimensions of a flask. The method involves pouring slime water into a transparent flask. Further, the slime water poured into the flask is stirred and time until settling begins i.e. appearance of a clear gap on the surface of the water and a dark thin strip of residue at the bottom of the flask is measured. The time up to the end of settling i.e. formation of clear water over the residue is also measured. Conditional end speeds are then determined by dividing the height of the liquid in the flask by the obtained time values. Further, the obtained time values are entered into a diagram of end speeds and the radii of particles 1 and 2 are determined as a function of the obtained conditional end speeds. The grain-size composition range is estimated taking into account 10% deviation of extreme values from the relationship 2r₁+10%≥d≥2r₂-10%, where d is the particle diametre in m; r₁ is the particle radius at the begging of settling in m; r₂ is the particle radius at the end of settling in m.

EFFECT: simplification of the method and increased accuracy of estimating the size of fine dispersed particles in slime water.

2 dwg, 1 ex

Description

The invention relates to gravitational sedimentation and can be applied in mines and concentration plants to analyze the range of particle sizes in sludge waters.

There are various methods [1] for assessing particle size, including sieve analysis, including analysis on microsieves.

The disadvantages of the analysis are the high complexity and sophisticated laboratory equipment.

Known methods for determining the final sedimentation rate of particles [2] in accordance with the laws of Rittinger, Allen, Stokes, Lyashchenko, valid in separate zones of the size of suspended particles.

The disadvantages of the methods is the inability to unequivocally solve the inverse problem: determining the final particle size velocity, because it is not known which law should be used.

The present invention solves this problem based on a unified law (combining the laws of Rittinger, Allen, Stokes), which takes into account the influence of the adhesion, cohesion and parachute effects of suspended particles in a unique dependence on the particle size [3, 4, 5, 6].

The solution of this problem is achieved by the fact that sludge water, poured into a transparent flask, is mixed and time is measured before the start of precipitation, i.e. the appearance of a light gap at the surface of the water and a dark thin strip of sediment at the bottom of the flask, and the time until the deposition ends: the formation of light water over the sediment, and then determine the conditional final velocities by dividing the height of the liquid in the flask by the obtained time values, which are plotted on the final velocity diagram and determine the particle radii r ₁ and r ₂ as a function of the received conditional finite velocity range wherein the particle size distribution is evaluated with the 10% deviation extreme values depending on 2r ₁ + 10% ≥d≥2r ₂ -10%, rD d - diameter of the particle, m; r ₁ - radius of particle precipitation onset, m; r ₂ is the radius of the particles of the end of the deposition, m

The implementation of the method is illustrated by drawings.

Figure 1 presents the successive state of sludge water in the flask.

Figure 2 shows a diagram of finite velocities for particles with different densities in accordance, constructed from mathematical dependences obtained by B. M. Stefanyuk, combining with the combined law the laws of Stokes, Allen and Ruttinger set forth in [3, 4, 5, 6 ].

An example implementation of the method.

Slurry water is poured into the flask. The height of the water in the flask h = 200 mm = 0.2 m.

The time to the beginning of deposition is τ ₁ = 7 min 45 s = 465 s, the time to the end of sedimentation is τ ₂ = 2 hours 25 min = 145 min = 8700 s.

Final speeds will be equal

V _k1 = 0.2 / 465 = 0.00043 = 4.3 · 10 ^-4 m / s;

V _k2 = 0.2 / 8700 = 0.000023 = 2.3 · 10 ^-5 m / s.

With an average density of solid particles ρ = 2000 kg / m ^3, points A and B in FIG. 1 correspond to radii r ₁ = 1.2 · 10 ^-5 m and r ₂ = 2.1 · 10 ^-6 m.

2r ₂ -10% ≤d≤2r ₁ + 10%;

3.78 · 10 ^-6 m≤d≤26.4 · 10 ^-6 m.

The proposed method does not require special laboratory equipment.

Literature

1. Perov V.A., Andreev E.E., bilenko L.F. Crushing, grinding and screening of minerals. - M .: Nedra, 1990. - P.19.

2. Handbook of coal preparation. - M .: Nedra, 1984. - S.170-171.

3. Senkus V.V., Stefanyuk B.M. Physical-electric clarification of sludge in the coal industry. - M.: Mountain Information and Analytical Bulletin No. 7, 2007. - S.79-84 / 80.

4. Stefanyuk B.M. Water structure and clarification of slurry water in mines. - Novokuznetsk // Sat. tr “Modern technology for the development of mineral deposits”: SibGIU, 1998. - P.104-109 (Fig. 1, formulas 14, 16).

5. Stefanyuk B.M. Reduced energy costs of hydraulic coal mining technology. Abstract. thesis for a job. student senior doctor of technical sciences for special. 05.15.11 - “Physical processes of mining”. - Kemerovo, Institute of Coal and Coal Chemistry SB RAS, 1998. - P.34 (Fig. 5, p. 372).

6. Stefanyuk B.M. Reduced energy costs of hydraulic coal mining technology. Dissert. for a job. student Art. Doct. tech. sciences for special. 05.15.11 - “Physical processes of mining”. - Kemerovo, Institute of Coal and Coal Chemistry SB RAS, 1998, Sec. 7.4. - S.295-305 (formulas 7.59, 7.72, fig. 7.15-7.17).

Claims (1)

A method for assessing the range of particle size distribution of finely dispersed particles in sludge water, comprising measuring the sedimentation time and the linear dimensions of the flask, characterized in that the sludge water poured into a transparent flask is mixed and time is measured before the deposition begins, i.e. the appearance of a light gap at the surface of the water and a dark thin strip of sediment at the bottom of the flask, and the time until the deposition ends: the formation of light water over the sediment, and then determine the conditional final velocities by dividing the height of the liquid in the flask by the obtained time values, which are plotted on the final velocity diagram , and determine the particle radii r ₁ and r ₂ as a function of the obtained conditional final speeds, while the range of particle size distribution is estimated taking into account 10% deviation of the extreme values according to the dependence 2r ₁ + 10% ≥d≥2r ₂ -10%, g de d is the particle diameter, m; r ₁ is the radius of the particles of the beginning of the deposition, m; r ₂ is the radius of the particles of the end of the deposition, m

Images