Feasibility of recovering metals from associated slags
The associated mineral ore accompanying Valuable Metal Compounds (VMC) have been usually treated in a smelting furnace ,such as Blast Furnace, Reverberatory, Blowing Furnace, hence the VMC were mostly concentrated into the molten associated slags and separated from liquid metals. So the associated slags become an important man-made resources (Table I), in which the VMC exist dispersively in various mineral phases with fine grain size1–4. Due to complex mineralogy and very fine mineral dissemination of the associated slags, it is difficult to recovery the VMC from the slags by metallurgical or mineral process conventionally . Based on several case studies in laboratory and practices in pilot plant on the associated slags , there occur a feasibility to recovery the VMC from the slags by a new process-Selective Precipitation Technique (SPT) on which three continuous steps are involved (in Figure 1).
Thermodynamic Properties of the MgO-BO1.5-SiO2 System at 1723 K
To determine the thermodynamic properties of the MgO-BO1.5 binary system, the following reaction was used: MOn(in slag)+nC(gr.)=M(in liquid copper)+nCO (g) where MOn represents MgO or BO1.5. The activity coefficients of boron and magnesium in liquid copper were first determined by equilibrating pure liquid B2O3 or pure solid MgO with liquid copper under controlled CO partial pressure in a graphite crucible at 1723K: ln γB=0.82+2.81xB, ln γMg=-1.22 (xB≤0.106, xMg≤0.0013) The themodynamic properties of MgO and BO1.5 in MgO-BO1.5 binary slag at 1723K were determined as a function of composition by equilibrating the MgO-BO1.5 slag with liquid copper under CO atmosphere. In addition, the interaction parameter (eMgB) in the Cu-B-Mg alloy was determined to be -100 at 1723K.
Increasing pulp yield in kraft cooking of softwoods by high initial effective alkali concentration (HIEAC) during impregnation leading to decreasing secondary peeling of cellulose
Abstract Pulp yield can be improved by a more homogeneous delignification of the chips, achieved by improved impregnation prior to the cooking stage. Complete and efficient impregnation is obtained by increasing the diffusion rate by means of an impregnation liquor with a high initial effective alkali concentration (HIEAC). In the present study, the effect of HIEAC in the impregnation was evaluated and compared to a reference impregnation procedure and a prolonged impregnation. After the various impregnation scenarios, the alkali concentration was always adjusted to the same level in the beginning of the cooking stage. Impregnation with a HIEAC resulted in yield improvements by 1–1.5% units, due to a higher cellulose yield and possibly also to higher yield of glucomannan. The HIEAC with an even alkali distribution within the chips prior to the cooking stage resulted in a more uniform delignification carbohydrate degradation. Yield increase obtained by uniform delignification is due to both decreased shives content as well as less secondary peeling.