Stripping ratio

Seam thicknesses and depths vary tremendously. The most favorable deposits have shallow overburdens and thick seams that cover large areas. Acceptable stripping ratios, ie, overburden thickness to coal thickness, depend on the quaHty of the fuel. Ratios up to 10 1 have been used for bituminous coals, but lower ones are required for lignitic coals because of the lower heating value per unit weight. 

The Break Even Stripping Ratio (BESR) or the economic limit for surface operations in comparison with underground mining is therefore determined as ... 

Using Eqs. (2.12) and (2.17), the stripping section component balance line [Eq- (2.10)] can be expressed in terms of the stripping ratio... 

The condition where the reflux and stripping ratios approach infinity is termed total reflux. No feed enters the column and no product leaves. Both component balance lines coincide with the 45° diagonal line and are therefore furthest away from the equilibrium curve. Total reflux sets the minimum number of stages required for the separation. For Example 2,1, Fig. 3,lid shows that the minimum number of stages required for the separation is 6. 

The column operates at an arbitrarily fixed stripping ratio (i,e., all the operating lines on Fig. 7.12a to /"have the same slopes). 

Eor the cells of simple mode (Eig. 6A), feed is introduced into the liquid pool under the following three assumptions there is no appreciable bubble coalescence in the rising foam with the column foam leaving the liquid surface is in equilibrium with the completely mixed bulk solution and the bulk solute concentration is equal to the drain solute concentration. For a sufficiently long column, the separation ratio and the stripping ratio LJL. are given by Eqs. (15) and (16) ... 

Notes. AHLM module with initial conditions feed 40% H3PO4 WPA, containing 55.2 ppm Cd, 55.4 ppm Cu, and 290 ppm Zn carrier 0.5 mol/kg PVSH aqueous solution strip 2.0 mol/kg HCl. Membrane Tokayama Soda cation-exchange membrane CM-2. Feed carrier strip ratio = 2.5 1 2.5. Flow velocities (cm /min) feed = carrier = 90 and strip = 60. Soiiice From Ref. [6] with permission. 

Notes. (1) Feed/ earner/ strip ratio =4/1/3. (2) Fluxes data were averaged in the experimenting time ranges 24—72 h. (3) Source From Ref. [5] with permission. 

Effect of Feed to Strip Ratio. Further experiments were performed to Investigate the effect of feed-to-strlp (F S) ratio on americium transfer and to evaluate the possibility of concentrating the metal Ions simultaneously with removal. A linear relationship would be expected between the F S ratio and the concentration factor, the ratio of the final strip concentration divided by the Initial feed concentration assuming no complications arise. However, the results shown In Table IV Indicate the actual concentration factor Is much less than the F S ratio, possibly because a large fraction of the americium Is held In the membrane at the conclusion of the run. In addition, the relationship between the ratio and the percent transferred Is roughly Inverse because of the Increased amount of nitric acid transferred Into the strip solution with larger feed volumes. 

Americium, in nitric acid waste, 182 Americium transfer behavior cation exchange of strip solution, 186 effect of feed-to-strip ratio, 186 effect of nitric acid, 185 studied with hollow-fiber membrane, 183 Analytical models, to predict facilitation factors, 12... 

D approaches zero. Similarly, when the stripping ratio approaches infinity, the stripping section oon mnent balance line [Eq. (2.30)] reduces to... 

When the mining operation reaches a predetermined stripping ratio (tons of overburden/tons of coal), it is not profitable to continue and depending on the equipment available it may not be technically feasible to exceed a certain height of high wall. 

Stripping ratio The unit amount of spoil or waste (overburden) that must be removed to gain access to a similar unit amount of ore or mineral material. 

PolyMet Mining Corp. (PolyMet) is advancing the development of the NorthMet Project. The NorthMet deposit is located in northern Minnesota, adjacent to the historic Iron Range. The deposit was discovered in the 1960 s and consists of a large, magmatic, disseminated sulphide, polymetallic deposit with values in Cu, Ni, Co, Zn, Au, Ag and Platinum Group Metals (PGM). The shallow, tabular orebody may be mined by open-pit methods with minimal pre-strip and a low waste ore strip ratio. 

On the other hand, when HCl was employed as a stripping agent varying the acid concentration from 0.5 to 10 mol/dm a nil stripping ratio was found in all cases. Selective separation factors for Pd(ll), Pt(II), and Rh(III) at different HCl concentrations was observed when using XAD2/Alamine 336 resins, as can be seen in Figure 9.21. 

Driving torque values indicate the torque necessary to drive the screws into the pilot holes. Stripping torque values indicate the tightening torques which will strip the threads formed by the self-tapping screws. In many applications, a low driving torque with a substantial drive/strip ratio is of primary importance. 

Generally, the SLM technique offers many advantages over the more traditional solvent extraction for metal ion separations 27,28). A SLM system i) is dispersion-free ii) has a potential for use of a high feed to strip ratio to achieve a high... 

Several ionic liquid-based extraction systems for the separation of and recycling rare-earth elements (REEs) have been reviewed in this chapter. There is a great interest in applying ILs to the REE recycling process [14]. However, before IL-based extractions of REEs can be carried out on an industrial scale, there are certain IL factors that need to be considered comprehensively, such as cost, purity, acidity stability, viscosity solubility, density, electrical conductivity, electrochemical windows, extraction efficiency, selectivity, extraction mechanism, stripping ratio, and methods of recycling [14]. The continuing studies in the above areas are warranted. 

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