| The principle of "Shallow Layer Sediment" was discovered by Mr. Howatson of UK in 1886. Manufacture and utilization of relating various sediment devices with tilting plates and tubes in many countries have been over a period more than a half centuries. Prof. HedstrOm of Sweden put forward a new design of Elementary Separation Cell with shallow layer in 1967, and then Sala International AB etc. developed Lamella Clarifier/Thickener of which several sets were put into operation around 1970. Meanwhile systematically theoretical study on Tilting Shallow Layer process and equipment has been undertaken since some fifty years ago. Study reports published, however, have been lessened in the last ten years. The process and equipment of separation of solids settling in Tilting Narrow Upflow was newly developed in years around 2000. A breakthrough, therefore, has been made in which the experiments of Shallow Layer or Tilting Shallow Layer over a hundred years on two dimensional X-Y plane system have been lifted to a new phase of research/development on three dimensional X-Y-Z system. TNU is an abbreviation of tilting narrow upflow which is defined as "continuously upflowing inside a closed tilting passage with narrow cross section keeping constantly regular and even".An experimental laboratory setting of continuously running to simulate commercial operation was initiated and employed, involving a transparent TNU cell and auxiliary devices. Experiments illustrate that Re number can be a criterion of TNU's flowing state: laminar flow-Re<130, turbulent flow>00, and transitional flow-130< Re <200. Length calculation formula of transitional zone, in which turbulence at cross-directional feeding inlet changes into laminar flow, is derived. Laws of TNU velocity changing along its length and width are established: maximum Vmax = (3d pgsina) 8u, averaged Vo= (d pgsina) 3u, Vmax= (1.5 ~ 3.0) Vo when 60 < Re < 250, and cut-off size of settled particle depending mainly upon Vmax. Travel locus of settling quartz particles short-ranged in TNU can be expressed by a cubic equation with one unknown quantity: for locus;and their travel distance can be derived as lmax = (2Vo Vsc- sina) (d cosa) when Vmax = 2 Vo, and relative error between calculated distance and measured one is only +10 %. Settlingtest was conducted in a cylinder and TNU cell with static and running mineral pulp separately. Correlation between solid content in supernatant in the cylinder and in overflow from the TNU cell is of a quadratic equation with one unknown quantity; and correlation between the two cut-off particle's settling velocity (Vsc) is of an exponential equation. The law of TNU's percent of solids (X) changing along its length (y) can be quantified as follows under different Re number relating to different feed flowrate or TNU's velocity:y1 = 03662ln(x)+1.8027 ,Re=52.7;y2 = 1.0696X3-3.1012X2+3.6791X -0.0645,Re=72.6;y3 = 0.7305X3 -2.4917X2 +3.5477X-0.1932 ,Re=98.6Imported lamella design has been developed to a modern integrated components' design: three kinds of elementary components are integrated into TNU cell; and cells into assemblage and then assemblages into various types of TNU separator. Structural parameters and material quality of TNU separators are optimized with new breakthrough in: [1] lower limit of the length of TNU or tilting plate is shortened from 2.S m down to 1 m or less; [2] thickness of TNU or space between two plates can be reduced from SO to 20 mm; and [3] theoretical inclination of TNU or tilting plate is improved from 45 to the scope of 45 to 77.2 from which the best figure can be chosen based on separators' maximum capacity per unit floor area.Four types of separators have been commercialized. TNU solid/liquid separator-thickener and liquid/solid separator-clarifier have been applied in many provinces of China. Newly developed TNU solid/solid separator-hydro-classifier is used at great scale in ilmenate concentrators of Panzhihua Steel Group and Chengde Steel Work; and extended to tin ore plants in Hunan and Yun...
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