Tower Mill Research Articles

タワーミル粉砕機の生まれと育ち

タワーミル粉砕機の生まれと育ち

タワーミル（ＫＷ‐１５００）による排煙脱硫用石灰石の微粉砕

タワーミル（ＫＷ‐１５００）による排煙脱硫用石灰石の微粉砕

タワーミルＫＤ‐３型粉砕機においてサイクロンの構造が粉砕産物に与える影響

The tower mill is a new type of pulverizer specially conceived for a fine grinding of minerals. Its efficiency of the fine grinding largely depends on the structure of the cyclones. In this paper, to investigate influence of the cyclone structure on fine grinding, the weight, particle diameter of the products as well as the electric consumption were examined using 10 different structures of the cyclone and a limestone sample. The experimental results are summarized as follows: (1) The different structure of the single and twin cyclones have no influence on the pulverized products. (2) In the case of cyclone with spiral ribbons, the weight of cyclone products increased, the maximum and 50% particle diameters of the products became smaller than the other cyclones. (3) In the case of cyclone with the spiral ribbons of every 44mm pitch, the weight of cyclone products increased, and the 50 % particle diameters of products were coarser than that for the other spiral cyclone, and the electric consumption of blower decreased. (4) The cyclone have no influence on the maximum size and the 50 % particle diameters of products in the classifying column. (5) The 50 % particle diameters was proportional to the maximum particle size of the tower mill products in any case of cyclone.

タワーミルＫＤ‐３型粉砕機において撹はんスクリューの回転速度が粉砕効果に与える影響

In the few studies devoted to increase the grinding efficiency of a Tower Mill Pulverizer, it has been possible to produce particles finer than 10μm. The problem now is to increase effectively the weight of fine particles in the products. To achieve this goal the weight and particle size distribution of products, and also the electric consumption of the Tower Mill KD-3 were investigated by varying the speed of the stirring screw from 1.08 s-1to 1.58 s-1.The results of the tests can be summerized as follows:(1) The weight of products in the classifying column and the cyclone, and the electric consumption of the stirring motor increase with the speed of the stirring screw, while the specific energy (J/kg) remains constant.(2) The particle size distribution of the products in the classifying column and the cyclone are not influenced by the stirring screw speed.

The Tower Mill: An archaeological excavation of Queensland's oldest extant building

The Tower Mill, Brisbane's oldest extant building, was excavated by the University of Queensland to determine for the Brisbane City Council the heritage potential of surrounding subsurface deposits. Following the employment of GPR, excavation revealed interesting stratifications, features and artefacts. Analysis permits an explanation for these deposits which augment an already fascinating history of the site's use over the past 170 years or so.

Use of grinding and liberation models to simulate tower mill circuit performance in a lead/zinc concentrator to increase flotation recovery

The paper presents findings from collaborative research on fine grinding, coordinated by the Australian Mineral Industries Research Association. The data reported here were collected from a tower mill circuit in the low grade mineral section of Mt. Isa Mines' Hilton Concentrator. Multi-component modelling, based on assays of size fractions, showed that the circuit was capable reducing the fresh feed from 110 to 15 μm at the desired throughout using about 22 kWh/t, provided classification at around 27 μm was installed. A benefit of about 3% recovery of both lead and zinc was indicated. A new simplified method of modelling grinding and liberation together is explained and verified by using parameters from the normal grind to predict, quite accurately, the size reduction and liberation achieved in a finer grind.

タワーミル粉砕機（ＫＤ−３型機）における微粒子実収率を高めるための捕集部と分級部の改良

In the previous studies on pulverization of limestone by a Tower Mill Pulverizer, a product containing particles finer than 10μm could be obtained using a newly developed Tower Mill KD-3. From now, the Tower Mill KD-3 needs a higher level of efficiency for its further development, that achieves a high recovery of fine particles from the pulverized products. With this purpose, a series of investigations have been carried out on different types of cyclones and classifiers to clarify the factors which could affect the recovery of pulverized particles: Single Cyclone with Spiral Ribbons (SCSR), Twin Cyclone (TC), Twin Cyclone with Spiral Ribbons (TCSR), Simple Classifying Part (SCP), Classifying Part with Inclined Sieves (CPIS).The results of these investigations can be summarized as follows:(1) An increase in the recovery of fine particles was recorded using a TCSR and a CPIS. In both cases the achieved performances are certainly due to the high air flow rate in the cyclone.(2) The relationships between the maximum particle diameters and the 50 % particle diameters of the products were approximately straight lines whatever cyclones and classifiers were used.

分級部を改良した新しいタワーミル粉砕機（ＫＤ‐３型）の開発

The authors have studied pulverization of limestone by the Tower Mill to develop more valuable uses of this resources. In the process of this study, the Tower Mill KD-3, a modified version of the Tower Mill KD-2, was used as equipment. As for the KD-2, this type is composed of three parts: comminuting, classifying and collecting part. But in the KD-3 classified coarse particles are settled in the bottom of the classifying part for another products. It is worth noticing that the air flow through the nets set improved classification of ground particles. In each experiment, to investigate the factors affecting the weight and the particles size of pulverized products, the weights of steel balls, limestone and the number of revolutions of screw were kept constant, while the grinding part and the air flow rate (Um) in the classifying part were varied.The results obtained are summarized as follows: 1) The fine particles classified in the classifying part flow into the cyclone smoothly with the air while the coarse particles are settled in the bottom of the classifying part for another products because of the modified structure of this classifying part and the set nets.2) The weight of products were affected by the dead space in the comminuting part, the inlet surface area and the number of spirals in the cyclone.3) The ratio of secondary particles influenced the weight of the-10μm particles and the 50% particles diameters in the product.4) The maximum values of the particle diameter (Dmax) in the product collected by the cyclone were found to be in accordance with the Stokes's law.5) The decrease and uniformity of the flow rate made the Dmax values smaller.6) The minimum value of Dmax was: 8.2μm for products collected by the cyclone; 14.7μm for another products settled in the bottom of classifying part.

タワーミルＫＤ‐２型粉砕機による石灰石の微粉化に関する研究

The Tower Mill KD-2 is a modified version of the Tower Mill KD-1 developed for grinding limestone. In comparison with KD-1, this new equipment is performed with three clearly defined parts: comminuting, classifying and collecting. Furthermore the inside diameter of the column classifier was enlarged (to 780mm) to regulate of ground particle velocity and the comminuting cell provided with two tapers (slope at the bottom of comminuting part) of different size.Experiments were carried out to investigate the taper effect on ground particle. As a result, weights of products and the 50% particle diameters were found higher using the small taper than the big one, but the maximum values of the diameter of the ground particles (Dmax) were similar.In regard to Dmax compared with the Tower Mill KD-1, the following have been established: 1) Pulverization of limestone under a flow rate lower than 0.06m/s is improved using the Tower Mill KD-2 and the minimum Dmax value is founded to be a 15.5μm.2) Dmax values distribution above the estimated curve assumed by stokes's law indicate that it will be possible to produce finer particles by improving the classifying part.

タワーミルの新用途例“活性水酸化マグネシウムの製造方法”

タワーミルの新用途例“活性水酸化マグネシウムの製造方法”

The Use of Power in the Early Industrial Development of Hull

Abstract Although never a major industrial town, Hull has a long history as one of the country's leading ports, having particular links with the Low Countries and the Baltic. During the eighteenth century the merchants had a need for power to process imported raw materials but due to the nature of the terrain, the town had no head of water to power wheels. Consequently some of the first ventures into rotary steam power occurred in the town, but this occurred, paradoxically, at the same time as the windmill was being transformed from the traditional wooden post mill into the sophisticated tower mill, using the latest technology and materials, and producing some of the country's finest windmills of the period. For most of the nineteenth century wind and steam power existed side by side, with wind power being used for a variety of industrial purposes in addition to flour production.

The Use of Power in the Early Industrial Development of Hull

Although never a major industrial town, Hull has a long history as one of the country's leading ports, having particular links with the Low Countries and the Baltic. During the eighteenth century the merchants had a need for power to process imported raw materials but due to the nature of the terrain, the town had no head of water to power wheels. Consequently some of the first ventures into rotary steam power occurred in the town, but this occurred, paradoxically, at the same time as the windmill was being transformed from the traditional wooden post mill into the sophisticated tower mill, using the latest technology and materials, and producing some of the country's finest windmills of the period. For most of the nineteenth century wind and steam power existed side by side, with wind power being used for a variety of industrial purposes in addition to flour production.

タワーミルＫＤ‐１型粉砕機による石灰石の微粉化に関する研究

タワーミルＫＤ‐１型粉砕機による石灰石の微粉化に関する研究

タワーミルによる石炭微粉砕

タワーミルによる石炭微粉砕

The Restoration of Jill Mill, Sussex

Jill is a post mill owned by Mid Sussex District Council and situated on the crest of the South Downs at Clayton, to the north of Brighton (Grid Reference TQ 303 134). Close by is neighbour Jack, a tower mill, completing a superb picture. Restoration of Jill from near dereliction to working condition has largely been undertaken by The Jack and Jill Windmills Society for the Preservation of Jill Mill, a charitable trust whose work led to grain being ground again in 1986 and to their gaining the Dorothea Award for that year.

Tower mill and its application to fine grinding

The Tower mill is a vertical stirred mill using steel balls or pebble grinding media. This device is designed for fine grinding at significant power savings when compared to conventional tumbling mills. This paper describes the machine and its operation, application, and performance for wet grinding.

タワーミルによる石灰石の微粉化

タワーミルによる石灰石の微粉化

タワーミルによる石灰石の微粉砕

Limestone was pulverized by the Tower Mill Pulverizer in dry batch and semi-continuous systems under various conditions in order to examine the characteristics of the pulverizing system. It was found that the system was characterized by an air flow rate which is induced by the blower mounted to the pulverizer for conveying the pulverized products, and the rate was affected by the number of revolutions (NR) of the blower and the weights of limestone (WL) and steel ball (WB) in the pulverizer. The increased value of NR and the decreased values more than the optimum ones of WL and WB respectively increased the weight of the pulverized product. The increased values of NR and WB and the decreased value of WL respectively decreased the weight percent of the -10μm particles in the product. While the increased value of NR caused an increase in the electricity consumption of the motor of the blower, it decreased that of the pulverizer, and the increased value of WB increased that of the pulverizer. The minimum values of the total electricity consumption per unit weight of the pulverized product and per unit weight of the -10μm product were 0.0494 and 0.527 kWh/kg with the respective capacities 23.6 and 2.25 kg/h, respectively.

石灰石の微粉化に関する研究

Most of the limestone produced is used as raw material for cement, iron and steel industries, and various civil engineering projects. Some of the limestone used which is of very high grade could be more profitably used for paper filler than for cement manufacture. The present paper was thus focused on problems related to limestone pulverization for paper filler production.1) Limestone of high grade purity and whiteness was pulverized by Tower Mill Pulverizer in a dry system.2) Tests were performed under various conditions in order to determine the one most suitable for the pulverization of limestone.3) The particle size distribution analysis was performed by the Sedimentation Balance.4) The most suitable pulverizing condition was as follows;The weight of the pulverizing medium (steel ball) was 40 kg, the number of revolution of blower was 1260 rum and the weight of feed (limestone) was 3.5 kg.

Report of Tower Mill's Operation (used at Tsuchikura Mine) Since 1953

Report of Tower Mill's Operation (used at Tsuchikura Mine) Since 1953