Sukeyuki Mori

Zeta potential of coal fine-particles in aqueous suspension

Abstract The relation between the zeta potential of coal fine-particles and pH value of suspension in aqueous suspension for different kinds of coal samples was determined by using a rectangular micro-electrophoresis cell. The empirical equation of the relation between the zeta potential of the particles and the chemical components of coal samples was determined in aqueous suspension of different pH values. The equation is represented as follows: Z = B C × (C) + B H × (H) + B O × (O) + B N X × (N) + B S × (S) + B A × (A) where Z is the zeta potential of the particles, (C), (H), (O), (N), (S) and (Ash) are weight percent of carbon, hydrogen, oxygen, nitrogen, sulphur and ash, respectively, and B C , B H , B O , B N , B S and B A are coefficients of each of the respective components of coal samples. The above coefficients were calculated numerically by the least-square method in suspensions with different pH values. The values of the coefficients, B C , B H , etc., (mV/%), indicate the zeta potential of each respective single component; viz. carbon, hydrogen, etc., of the coal samples. When the chemical components of a coal sample are known, the zeta potential of the coal fine-particles can be determined by the equation with the coefficients obtained in suspensions with different pH values.

Flocculation and dispersion properties of quartz and fluorite particles in suspension

Abstract An improved sedimentation balance was developed that has a maximum weighing load of 200 g and weight detection sensitivity of 0.1 mg for the particle size distribution analysis of mineral particles in suspension. The sedimentation balance was used to determine the falling velocity distribution curve (which corresponds to the particle size distribution curve) of suspended particles in aqueous suspensions in order to investigate the flocculation and dispersion properties of quartz, fluorite and a mixture of equal weights of both particles in relation to the zeta potential of mineral particles. Whereas quartz and fluorite particles dispersed in separate acid suspensions of about pH 7 or less, a mixture of equal weights of both quartz and fluorite particles flocculated in a third suspension of about pH 10 or less. This phenomenon is possibly explained by the heteroflocculation of quartz and fluorite particles, which are negatively and positively charged, respectively, in the suspension of about pH 10 or less.

Relationship between Bond's work index (Wi) and uniformity constant (n) of grinding kinetics on Tower mill milling limestone

Abstract In the theory of grinding kinetics, the grindability of a material is the only factor used to determine the required size of a grinding machine. So for users of the Tower mill, this grindability is expressed through Bonds work index (Wi). However, the uniformity constant (n), which is found empirically by using a small Tower mill and is expressed also as the grindability of material, can be of great help to designers in the determination of the real parameters of a Tower mill. The present study is an approach to establish a relationship between the Bonds third theory of comminution and the above-mentioned constant of grinding kinetics. The validity of the obtained relationship, [n]=1.47−0.309 ln [W i ], has been confirmed with a correlation coefficient of 0.855** through a regression analysis of 22 samples of limestone.

Studies on comminution mechanism of the dry tower mill KD-3

Abstract In order to obtain economically lot of fine particles, a dry tower mill KD-3, composed of a comminuting section, a classifying column and a collecting section, has been developed through this study. Grinding tests were carried out on limestone to clarify the comminution mechanism in the KD-3. A particular attention was paid to important factors such as the size of the grinding media (steel balls of10 mm,13 mm,16 mm,20 mm), the speed of the stirring screw (from 1.08 s −1 to 1.58 s −1 ) and the role of the net in the classifying column. The study has revealed an optimum efficiency for steel balls of20 mm size and a stirring screw rotating at 1.58 s −1 . Besides, a series of nets settled in the classifying column have improved the efficiency of the classifying operation by reducing the buoyancy of the materials and regulating the maximum size of products collected in the cyclone (d max is about 10 μm). The air flow rate in the duct and the pressure of drops in the column were approximately quadratic curves, but the d max of products collected in the cyclone was proportional to the pressure of drops in the classifying column.

Recovery of Non-Ferrous Metals from Car Scrap using the Jig Separator (ECHO Metal Jig, Type-SP).

Today, the non ferrous metals such as copper, brass, lead and zinc in car scrap are not systematically recovered, although the iron and the aluminum contained in car scrap are recovered. Therefore, for the recycling of resources and the preservation of natural environment, we started to make a study of recovery system of the non ferrous metals from the car scrap. In this paper, we conducted the separation experiments by using the ECHO Metal Jig (Type-SP) with jig box having the dimension of 250mm in width, 250mm in length and 300 mm in height, which is particularly made for an experimental purpose. And -10mm shredder dust abandoned in the scrap factory is treated with this jig and separated into three products (non metal dust, middling and non ferrous metal concentrate). The effect of gate height, feed speed and pulsation time for middling separation has been investigated.The results obtained through the experiments are summarized as follows;(1) The gate height at middling separation; Most effective factor is the gate height at middling separation.When the gate height is higher, the weight and the recovery of concentrate increase and the grade of that decreases, and vice versa.(2) The feed speed; Throughout this test, 0.54kg/s of feed speed gives maximum concentrate recovery and the best separation performance.(3) The Pulsation time for middling separation; The pulsation time for middling separation has no effect on the grade, recovery of the concentrate and the separation performance.(4) The best operating condition of this jig is as follows; 200mm of gate height at middling separation, 20s of pulsation time for middling separation and 0.54kg/s of feed speed.(5) This jig is very effective for -10mm shredder dust, since over 90% of valuable metals having over 7.0 of specific gravity is recoverable with this jig separator.

Treatment of Suspended Solids in Waste Water by Hetero Flocculation Phenomena with Fluorite

In waste water, impurities are present as suspended solids or dissolved substances Usually for the treatment of fine suspended solids and microorganisms residues after biological processing, organic or inorganic flocculants are added to fasten the settling velocity of particles through the formation of large flocs. However the sediments obtained with organic flocculants have a high moisture content, and the use of inorganic floc-culants is restricted because of the tendency of flocculant ions to remain into the clarified water. To overcome these problems, authors have been studying the development of a new method of waste water treatment by the hetero-flocculation with fluorite. In the present study, the effect of fluorite as solid flocculant has been investigated using waste water containing clay, organic matters and microorganisms. A suspension of fluorite was more effective for the treatment of clay waste water. In the cases of waste water containing organic mat-ters and microorganisms, a remarkable hetero-flocculation was observed when these waste waters were diluted to 8000 and 3500 mg/l, respectively. The dehydration can be easily carried out for each waste water

The Flocculation Phenomena of the Mixed Quartz and Fluorite Particles with a Definite Particle Size Fraction.

It is important to clarify the flocculation phenomena for the mineral processing such as waste water treatment. For this object, experiments on the flocculation phenomena have been carried out using quartz and fluorite particles which are negatively and positively charged in distilled water, respectively. In the present study, suspensions containing the particles smaller than 4.6μm (fine particle suspension) and larger than 9.3μm (coarse particle suspension) are prepared to understand the flocculation phenomena of the mixture of fine quartz-fine fluorite particles, fine quartz-coarse fluorite particles, fine fluorite-coarse quartz particles and coarse quartz-coarse fluorite particles in the different pH values. It is found that fine quartz and fluorite particles homo-flocculate at pH about 2 and pH over 11, while coarse quartz and fluorite particles do not homo-flocculate at all pH range. In the experiments conducted with the mixture of fine quartz and fluorite particles in equal proportion, the electric gravitation between them has led to the hetero-flocculation at all pH range. When fine quartz and coarse fluorite particles are mixed, it is considered that the hetero-flocculation such as coarse particles are coated with fine particles would occur at all pH values. Besides, homo-flocculation of fine quartz particles can be also observed at pH about 2. In case of the mixture of fine fluorite and coarse quartz particles, the hetero-flocculation such as coarse particles are coated with fine particles and homo-flocculation of fine fluorite particles are supposed to occur at all pH values and at all pH values, respectively. Remarkable flocculation phenomena can not be seen in mixing coarse quartz and coarse fluorite particles at all pH values.

A Study on the Stabilization of Shredded Automobile Residues

The number of scrapped cars amounts to about 5 million a year in Japan and the increase in shredded automobile residues from scrapped car processing causes social problems such as the shortage of disposal places and soil pollution. The research on the characterization of shredded automobile residues was performed to overcome these problems. It was found that lead in the residues but existed as fine particles and adhered to cotton and sponge. The stabilization of the lead after mixing with additives was investigated by lead contamination analysis. The additives used was cement, sodium carbonate and K-20. It is worth noticing that the addition of 5 weight percentage of cement powder without water followed by 3 minutes stirring and 4 hour aging is effective to suppress lead inclusions.

Hetero-flocculation Phenomena in Waste Water Treatment with Artificial Fluorite Suspension.

Waste water from mineral processing factories and organic chemical factories usually includes fine solids such as minerals, organic particles and microorganisms which can be removed fastening their settling velocities through flocculation. Generally organic flocculants have been used to treat the fine solids, but it is hard to deal with the obtained sediment because of the moisture including in it. The use of inorganic flocculants is limited because of the tendency of flocculant ions to remain into the clarified water. To cope with these problems, authors have been studying the development of a new method of waste water treatment by hetero-flocculation with fluorite. From the previous study on the treatment of two types of waste water (fluorite flotation tailing and bauxite residue from an alumina refining factory), it is found that artificial fluorite suspension in small quantity is more effective. In this study, the effect of artificial fluorite suspension as flocculant has been investigated using fluorite flotation tailing, organic matter after processing acrylic resin and microorganism after C. O. D treatment. It is noticed that the supernatant concentration of fluorite flotation tailing (height of 32 mm) reduces by hetero-flocculation for a few minutes when a small quantity of artificial fluorite suspension is added. The diluted waste water of organic maters and microorganism on the other hand are flocculated by the addition of a little of an artificial fluorite suspension and each supernatant concentration decreases.

Characterization of Shredded Automobile Residues

The increasing amount of shredded automobile residues has generated a new policy to their disposal and treatment. Accordingly, a complete knowledge of the residues characteristics is of great importance to cope with the soil pollution and the shortage of land filling space.Following this goal, the present study is also a first step in the process of reducing the shredded automobile residues and stabilizing hazardous substances. It was then found that the shredder residues are composed of cottons and sponges like metals, plastics, rubbers, glasses and small stones, metals, and electric wires. In addition the weight percentage of organic materials is about 70%. It is worth noticing that in small and large particle size fractions the lead contamination is relatively low but cotton and sponge like materials include more lead inclusions than any other components. These inclusions do not have an ion origin. There are fine particles, mainly in the range of 0.1-1.0 μm, as shown in the lead determination analysis using different filters.