Water Clarification by Flocculation
The chemicals involved in the work of this paper utilize a combination of mechanisms: charge effect neutralization and polymer bridging. There are a number of trends in the results that support this dual mechanism. The slow settling rate and insensitivity of changes in coagulant concentration are the typical effects of compounds used for charge neutralization. […]
Acidic Mine Tailing Neutralisation – Vegetation
Field tests on 20-year-old acidic copper tailing showed that after treatment with combinations of dolomitic lime, limerock, fertilizers, and/or sewage sludge, vegetation can be successfully established. Plant coverages, 4 years after seeding, ranged from 30 to 80 percent, even though neutralization of the acidic tailing with either lime or limerock was only partially effective. Chemical […]
Zinc Electrowinning & Zinc Cathodes
Commercial production of zinc by electrolysis began in 1881 following a patent by Letrange of France. The process has come down to the present day essentially unchanged and consists of three basic steps: Leaching of roasted zinc concentrates in dilute H2SO4; for example, ZnO + H2SO4 → ZnSO4 + H2O. Purification of the resulting zinc sulfate […]
Titanium Oxide or Titania Pigment by Ilmenite
Titanium dioxide or titania pigment is prepared commercially from ilmenite, an iron-titanium oxide mineral, by the sulfate process. Ilmenite is digested with H2SO4 to yield a titanium sulfate solution. Subsequently, the solution is hydrolyzed to yield a hydrous titania precipitate that is calcined to produce pigment. A major problem associated with the process is the […]
Structural Analysis of Grinding Mill Shells
Accurate modeling of structures by finite elements requires not only that the user estimate the load paths, and areas of stress concentrations or rapid variations, in a structure, but also that he realize the modeling idiosyncracies of each element he is working with. He needs to know limitations in displacement function assumptions, aspect ratios, angles, […]
Inert Gas Generator
Belt Conveyor Reclaim Tunnels
Whenever the material and soil conditions permit its use, a belt conveyor in a reclaim tunnel is the most economical reclaim device due to its very limited manpower requirements and utilization of gravity to make the ore flow to the feeder opening. This dependence on material flow limits the belt conveyor in a reclaim tunnel […]
Aluminum Chloride Solubility
A research program was conducted to improve processing technology for extracting alumina from nonbauxitic. The success of this program had provided the technology necessary for producing an adequate supply of high-grade alumina from domestic sources, thus meeting national economic and strategic needs relative to aluminum production. The hydrochloric acid process for recovering alumina from low-grade ores is one […]
Sizing and Operating Thickeners
This paper presents a development of thickening theory which provides a reliable and easy-to-use method for determining the size of continuous thickeners from batch settling tests. It also offers a description of thickener operation performance based upon the proposed method. Thickener Operation Figure 13 shows a log-log relationship between underflow concentration and unit area at […]
Accuracy Determination for Conveyor Belt Scales
Increasing capacity of bulk material handling systems creates difficult problems for accurate in-line material weight measurements. At the same time increasing system complexity and growing user demands call for more measurements. Precision in-line weight measurements for bulk materials are usually accomplished by application of conveyor belt scales. Belt scale accuracies listed by scale vendors are […]