When the ore is magnetically selected, the production capacity of the magnetic separator can be divided into two concepts of maximum production capacity and actual production capacity. The so-called maximum achievable capacity refers to the maximum separation indexes ore production capacity magnetic separator under satisfactory conditions; refers to the actual capacity is determined by the capacity beneficiation plant specific conditions. When selecting the type and quantity of the magnetic separator, the necessary reserves must be considered, so the actual production capacity parameters of the magnetic separator must be used. Where K g ——— the coefficient associated with the pulp giving the work area; Where g o ———free fall acceleration, m/s 2 ; Deoxidizing Agent,Desulfurizer for Mill Rolls,Desulfurizer for Steel Casting,Desulfurizer for Steel Shijiazhuang BeiKeDeRui Metallurgical Science & Technology Co.,Ltd , https://www.bkdrtech.com
The maximum production capacity that a magnetic separator can achieve is determined by the following three points:
(1) The recovery capacity of the magnetic separator, that is, the ability to recover magnetic particles from the layer or stream during the time that the ore passes through the recovery zone;
(2) The transport capacity of the magnetic separator, that is, the ability to transport the magnetic product from the recovery zone to the discharge zone;
(3) The ability of the magnetic separator to pass, that is, the maximum amount of material that the magnetic separator can pass per unit time.
The magnetic separator production capacity criteria listed above are closely related to each other and are affected by factors such as the physical and mineralogical properties of the selected ore and the structural parameters of the magnetic separator.
(1) Production capacity of dry upper ore magnetic separation maple The maximum achievable production capacity of dry upper ore mining magnetic separator Q (ton/hour is calculated by the following formula Q=3.6a m υ o υ o δ o nd' b (1)
Where a m ———the coefficient related to the content of magnetic particles in the ore (am=0.7 when the magnetic particle content a m >70%; a m ≈
50%, a m ≈1; a m ≤ 30%, a m = 1.3);
V o ———Ore filling coefficient [for ungraded material υ o =π(d'-d′′); for graded material d' and lower limit d′′ of graded material υ o =π(d′-d′′)/ 6 d'In (d'/d");
υ o ———The conveying speed of the ore through the recovery zone, m/s;
δ o ———ore density, kg/m 3 ;
n———the number of layers related to the ore particle size (for strong magnetic ore when d'>2.5cm, n=1; when 2.5≥d'≥
n = 1 to 3 at 0.8 cm; n = 3 to 5 when 0.8 ≥ d' ≥ 0.2 cm; n = 5 to 10 when d' < 0.2 cm. For weak magnetic ore m = 1 ~ having a particle size of less than 0.3 cm 3);
b———feed layer width, m.
(II) Production capacity of the lower-feeding wet-type cylinder magnetic separator The maximum achievable production capacity Q (ton/hour) of the lower-feeding wet-type cylindrical magnetic separator is determined by the following formula: 
K w ——— the ratio of the volume flow of the non-magnetic part of the slurry to the volume flow of the ore;
b———the width of the mining area, m;
p Æ’ --- the solid content in the ore, %;
ι a ———The length of the effective part of the recovery area, m;
d m ———magnetic particle (agglomerate) particle size, m;
χ bs ——— magnetic particle (aggregate) object specific magnetic susceptibility, m 3 /kg;
H———the magnetic field strength of the surface of the feed trough, A/m;
g o ——— free fall initial acceleration, m/s 2 ;
Δƒ—feeding density, kg/m 3 ;
η w ———Medium viscosity, pa•s.[next]
For downstream and semi-reverse flow magnetic separator K g ≈1; for countercurrent magnetic separator K g ≈ 0.6. For downstream flow separator K w =1; for countercurrent and semi-reverse flow magnetic separator K w is determined by:
K w =1-γ m (R m +1/δ m )/(R ƒ +1/δ ƒ ) (3)
Where γ m ———the yield of magnetic products, %;
R ƒ and R m — the mass-to-liquid ratio of the ore and magnetic products, %;
δ ƒ ———The density of solids in the ore, kg/m 3 .
(III) Production capacity of wet induction roller strong magnetic separator The maximum achievable production capacity (ton/hour) of wet induction roller strong magnetic separator is determined by the following formula:
Q=2.10 -3 K g ι a d 2 m δ m bΔ ƒ p ƒ (μ o χbsHgradH-g o )η w (4)
Equations (2) and (4) are correct only when the magnetic separator delivers sufficient magnetic product and slurry throughput.
(IV) Influence of molecular force The role of molecular force between fine particles in dry magnetic separation is particularly obvious. Calculated F = 2Aπd 1 d 2 σ s (d 1 + d 2) (5) between the two spherical gold particles Jie Liya available molecular force F (ДepЯrNH) Formula
Where F———molecular force, N;
A—the coefficient related to particle contact area, humidity and other factors;
d 1 and d 2 ———particle diameter, m;
σ s — surface tension at the interface between the particles and the surrounding medium (air), N/m.
When the contact particles are of equal diameter,
F=Aπdσ s (6)
When the particle adhesion is equal to the gravity, the particle diameter is:
δ———particle density, kg/m 3 .
Magnetic and non-magnetic particles smaller than d will form a combination. If the magnetic susceptibility of the combination is large enough, it will enter the magnetic product; otherwise the combination enters the non-magnetic product. This phenomenon will destroy the dry selection process and reduce its efficiency. Therefore, in order to improve the sorting index, dust is generally pre-dusted. When the fine material is dry-selected, additives are also commonly used to promote particle dispersion.
(V) Effect of solid content in the ore on the wet magnetic separation results The magnetic component content β m (%) in the magnetic product is approximately determined by the following formula:
β m =a m (a m +K t γ m a n R m /R f ) (8)
Where a m and a n — the content of magnetic and non-magnetic components in the ore (a n =1-a m )%;
K t ≈ 1.0~1.2———Non-magnetic particles are brought into the magnetic product coefficient;
γ m ———the yield of magnetic products, %;
R m and R f — the mass-to-solid ratio of the magnetic product to the ore.
Equation 8 shows that the quality of the magnetic product increases as the slurry is diluted (R f is increased).
It is important to keep the feed of the magnetic separator stable during magnetic separation, not only the weight but also the solid content. Doing this must stabilize the grinding and grading equipment , which can be achieved using automatic adjustment techniques.
In the first stage of magnetic separation (derived magnetic products and tailings), the feedstock solids content is about 40%; in the subsequent magnetic separation section (selected final concentrate), the feed concentration is about 30%.
Magnetic separator production capacity and factors affecting the magnetic separation process