-
- دوشنبه تا شنبه: 10:00 - 16:00 / یکشنبه تعطیل است
Von Rittinger's law (1867): It states that the energy consumed in the size reduction is proportional to the area of new surface generated. putting p = −2, then integration gives: Writing C = KRfc. fc is the crushing strength of the material.L2 & L1 are the final and initial particle sizes.KR is the Rittinger's constant.
به خواندن ادامه دهید
Generally, grindability can be determined either based on "product constant fineness" method (Bond work index W i) or on "constant useful grinding work" method (HGI). The …
به خواندن ادامه دهید
The impact crushing strength of rocks so determined is used to calculate the Bond crushing work index using the expression (3.9) W i = C × I R e l a t i v e d e n s i t y o f s a m p l e kWh / t where. C = a constant which converts the impact crushing strength, numerically and dimensionally to the work index
به خواندن ادامه دهید
The product is then reduced further in a second crusher to 1.23 mm. If the work index is equal to 3.1, calculate the total power (kW) needed to crush the rock from its initial size using Bond's Law. 8. A ball mill grinds plastics to make a very fine powder. At the present time, 10000 kg of powder are produced per day.
به خواندن ادامه دهید
Bond's equation can be used in a number of useful ways: 1. Process and equipment design can use the equation by inputting the desired feed (F80) and product sizes (P80), measuring a work index value (Wi) in the laboratory and then calculating the specific energy consumption required of the process equipment (E). 1.
به خواندن ادامه دهید
mass of material is constant for the same reduction ratio, that is the ratio of the Volume surface mean diameter before and after crushing. W = P/m=K k * In (Ds1/Ds2) Where, K₁ = Kick's constant Bond's Crushing Law: A somewhat more realistic method of estimating the power required for crushing and grinding was proposed by Bond in 1952.
به خواندن ادامه دهید
E = K (P80 ⁿ – F80 ⁿ ) where K and n are empirical constants measured for your ore. One solution for this equation Bond's equation if K = (10·Wi) and n = –½. 1. Reference ore. Run a ...
به خواندن ادامه دهید
where E = crushing energy. K R = Rittinger's constant. F C = crushing strength of the material. 4.4. A Blake jaw crusher had the following dimensions: Gape = 160 cm, open …
به خواندن ادامه دهید
Contribute to lbsid/en development by creating an account on GitHub.
به خواندن ادامه دهید
dE/dL = KKfcL-1 which, on integration gives: = KKfc ln(L1/L2) (11.2) Equation (11.2) is a statement of Kick's Law. It implies that the specific energy required to crush a material, …
به خواندن ادامه دهید
The tested rock sample of a 500 g aggregate in the fraction 11.2–16.0 mm was inserted into the mortar.The friability value S 7 equals the percentage of undersized material, which passes through the 11.2 mm mesh after the aggregate test crushing in the mortar by weight-drops, the mean value for a minimum of three to four parallel tests being chosen …
به خواندن ادامه دهید
The formula for Hooke's law specifically relates the change in extension of the spring, x, to the restoring force, F, generated in it: F = −kx F = −kx. The extra term, k, is the spring constant. The value of this constant depends on the qualities of the specific spring, and this can be directly derived from the properties of the spring ...
به خواندن ادامه دهید
Hint: Rittinger's law may be written in the form E = K R f C 1 P 80 − F 80 kWh / t where E = crushing energy. K R = Rittinger's constant. F C = crushing strength of the material. 4.4. A Blake jaw crusher had the following dimensions: Gape = 160 cm, open set = 24.4 cm, close set = 5.0 cm. The width of the hopper was 1.5 times the gape.
به خواندن ادامه دهید
C and β are empirical constants This form is familiar, and it is reasonably easy to see Bond's Equation (Equation 1) is the special case where β = –0.5, and C = (10×Wi). The …
به خواندن ادامه دهید
A crushing mill reduces limestone from a mean particle size of 45 mm to a product: Size (mm) Percent. 12 0. 7 7. 5 45. 2 19. 1 16. 0 8. 0 3. 0 1. and …
به خواندن ادامه دهید
This law, named after Rittinger, is best suited for grinding rather than crushing. In case of crushing a classical law known as Kick's law is best suited: P = 𝑚̇𝐾 log 𝐴𝑤2 𝐴𝑤1 (4.4) A more useful relation that can be used for both crushing and grinding has been obtained by Bond (1952).
به خواندن ادامه دهید
Chemical processes are labeled as exothermic or endothermic based on whether they give off or absorb energy, respectively. 7.3: Exothermic and Endothermic Reactions is shared under a CC BY-NC-SA 3.0 license and was authored, remixed, and/or curated by LibreTexts. Atoms are held together by a certain amount of energy called bond energy.
به خواندن ادامه دهید
This is known as Hooke's law and commonly written: F = − k x. Where F is the force, x is the length of extension/compression and k is a constant of proportionality known as the spring constant which is usually given in N/m .
به خواندن ادامه دهید
work index approximate value is exactly the same as in the first two grinding cycles of. Prepare a sample, the same as for the standard Bond test (grind to . -3.327 mm). Determine the starting ...
به خواندن ادامه دهید
This paper investigates grinding of mineral mixtures with different grindabilities in the Bond ball mill. Understanding the ore mixture grinding is of great importance in mineral processing. The energy required for crushing and grinding is presented by the Bond work index and is determined by means of Bond grindability test. This paper presents the …
به خواندن ادامه دهید
Δ S univ = Δ S − Δ H T. Multiplying both sides of this equation by − T, and rearranging yields the following: − T Δ S univ = Δ H − T Δ S. Comparing this equation to the previous one for free energy change shows the following relation: Δ G = − T Δ S univ. The free energy change is therefore a reliable indicator of the ...
به خواندن ادامه دهید
Hooke's Law or the harmonic (i.e. quadratic) potential given by Equation (ref{5.1.3}) is an excellent approximation for the vibrational oscillations of molecules. The magnitude of the force constant (k) depends upon the nature of the chemical bond in molecular systems just as it depends on the nature of the spring in mechanical systems.
به خواندن ادامه دهید
The final form of Bond's equation can be written as [4]: (2) E = 10 C W i 1 P 80 − 1 F 80 kWh ton where C = a tabulated constant depending on type and condition (wet or dry) of comminution equipment, F 80 = 80% passing sieve size of the feed, μm, P 80 = 80% passing sieve size of the product, μm, W i = Bond work index: the work required to ...
به خواندن ادامه دهید
Where: E=Energy, K K =Kick's Constant, f c =crushing strength of the material, L 1 =initial length, and L 2 =reduced length. Bond's Law states that the total work input represented by a given weight of crushed product is inversely proportional to the square root of the diameter of the product particles. Bond's Law can be written as:
به خواندن ادامه دهید
Solution: Hess' Law for bond enthalpies is: ΔH rxn = Σ E reactant bonds broken − Σ E product bonds broken. The ΔH is given per mole of HF, so we need to use −269 x 2 = −538 kJ for the enthalpy of the reaction. −538 = [432 + x] − [ (2) (565)] x = 160 kJ. Example #6: Calculate the enthalpy change for the reaction of ethene and ...
به خواندن ادامه دهید
Confusion concerning the so-called general law of grinding proposed by Walker et al. is removed when it is realised that two forms of the law exist, quite different in physical meaning. The Kick and Rittinger laws are special cases of one form, and Bonds law is a special case of the other. Thus it is possible for Rittinger's and Bond's laws to ...
به خواندن ادامه دهید
Bond enthalpy (which is also known as bond-dissociation enthalpy, average bond energy, or bond strength) describes the amount of energy stored in a bond between atoms in a molecule. Specifically, it's the energy that needs to be added for the homolytic or …
به خواندن ادامه دهید
where e s is the surface energy per unit area, A p and A f are the surface areas per unit mass of the product and feed, respectively, and η c is a crushing efficiency. The later is likely to be very small, of the order of 1%. Using the definitions of specific surface and sphericity, the surface area per unit mass, for non-spherical particles ...
به خواندن ادامه دهید
S = k∑ 1n x M ; that is, the summation of the weights by the theoretical meshes, where k is a constant, six times the volume of unit weight of the rock.
به خواندن ادامه دهید
A. L. Coello-Valazquez. The Bond work index is one of the most useful and interesting parameters used in designing grinding equipment. However, it must be obtained under restrained conditions ...
به خواندن ادامه دهید