FR2517590A1 - PROCESS FOR THE PREPARATION OF A CERAMIC MATERIAL, IN PARTICULAR A MIXTURE FOR THE MANUFACTURE OF TILES AND INSTALLATION FOR THE IMPLEMENTATION OF THIS PROCESS - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS AND A PLANT FOR THE PREPARATION OF CERAMIC MATERIAL FOLLOWING WHICH, IN AN INITIAL STEP, A MIXTURE OF WATER AND SOLID MATERIAL IS INTRODUCED IN A CONSTANT RATIO IN A CONTINUOUS CYCLE MILL 6 UNTIL SLUDGE IS OBTAINED WHICH IS THEN FILTERED TO SEPARATE THE SOLID PART WHOSE SIZE IS GREATER THAN A PRESET VALUE; THIS SOLID PART THUS SEPARATED IS RECYCLED IN THE CRUSHER 6 WHILE A MEASURING DEVICE 14 CONTROLS THE DENSITY OF THE SLUDGE AND CONTROLS THE WATER SUPPLY 15 TO THE CRUSHER SO AS TO MAINTAIN THE PROPORTION OF WATER AND SOLID MATERIAL; THE SLUDGE IS THEN TRANSPORTED TO A HOMOGENEIZATION DEVICE 12.

Description

-1 2517590

  The present in Ten i on relates to a preparation process

  of ceramic material, in particular a mixture for the manufacture-

  tion of tiles, thus gu <m, Astalatiou for the implementation of this process The preparation of a ceramic diaper has consisted in the past, of introducing a basic ire (for example of coarsely pre-ground clay) 'ec addition of water, in a grinder where it is ground to N residual percentage desired to be

  then discharged at the fi-fluid or semi-fluid ft-k in reservoirs

storage storage.

  The resulting product, in sludge form, is then filtered and transported to stirring tanks, from which it is extracted in the street for further processing until some or all of it - ity of existing water is removed and a final product is obtained which may be present under the

in the form of a powder or a part.

  In particular, 1 r: qeion wishes to obtain a product in powder form, the mud is introduced into an apparatus, called an atomizer or a spray dryer, where it is atomized and brought into contact with a stream of hot air arranged to provide

  separation of the fluid part from the solid part.

  The conventional preparation processes have drawbacks which affect the quality of the final product and which

  involve high energy consumption.

  From the point of view of quality, it should be noted that the grinding process is p L} rsuii until a residual content pri: 1 e is obtained, which is periodically checked on sludge samples, Consequently , before the minimum residual content is reached we also submit to a

  advanced grinding of Ula particles which fall within the acceptable range

  gianulometry table This results in a proportional increase in the grinding time or else in a widening of the granulometry ranges while the residue of higher particle size cannot be eliminated r Ln same time The presence of this residue is disruptive in that it affects the following processing steps l In particular, when said residue contains, for example, certain properties resulting from the use of chips, such as copper granules, it occurs during

  the cooking stage a non-negligible formation of indefinite stains

Sirables and a Jor decclorate.

  -2- From an energy point of view, it should be noted that these

  known methods do not make it possible to establish op-

  timales for the grinding operation and for the following stages

  separating the fluid part from the solid part.

  In fact, taking into account that such treatment operations require a supply of heat, it is preferable that the water supply to the mill is reduced and that the flow rate of the mill is reduced from the maximum, in order thus to establish a situation of compromise In such conditions,

  material sorting is less efficient.

  The object of the invention is to provide a new method making it possible to substantially reduce the aforementioned drawbacks.

known methods.

  According to the invention, this object is achieved by the fact that this method comprises the stages consisting in grinding in a continuous cycle mill a mixture of water and a solid ceramic material of coarse particle size, until obtains a sludge having granulometry characteristics and a solid part / liquid part ratio approaching the desired values, recycling the sludge in a sorter so as to separate from the sludge a material having a granulometry exceeding a preset limit value, at reintroduce the separated material into the mill

  while transporting the mud to a homogenizing apparatus

  tion and storage, to measure said ratio in said sludge and to control the water supply to the mill according to

the measured value of said ratio.

  The invention also relates to an apparatus for implementing said method, this apparatus being characterized in that it comprises: a continuous cycle mill for grinding a mixture of water and solid ceramic material until that a slurry having density and particle size characteristics approaching the desired values is obtained, at least one sludge tank for receiving the sludge from the crusher, a pump for pumping said sludge from the container into a sorter acting so as to separating from the mud a material having a particle size exceeding a preset limit value, a means for transporting said separated material to the crusher

  and to transport the mud to a homogenizing machine

  tion and storage and up to a device for measuring the ratio between the solid part and the liquid part of the sludge, arranged

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  spur commander: 1 'a lint: atio in water dud it grinder for

  set the water / cerami matter ratio 3 eu.

  D'au Ltrest aanl-yges And features of the invention

  will appear on the screen: from the following description, given

  title of example noun limitative and on the appended drawing in which FIG. 2 is a sohematic street of an installation according to the invention,

  Figures 2 and 3 show variants of the app.

similar to Figure 1, and

  Figure 4 shows a variant of the grinder.

  Referring to Figure 1, the installation includes

  two hoppers 1, 2, ageno Vas to contain a material of granulo-

  coarse metrics, such as clay.

  From the hoppers, the material is recovered, for example by means of worm extractors 3 and 4, and it is transported to a belt conveyor 5 The conveyor transports the material to a continuous crusher 6 of design - Conventional tion, for example of the gravity type with balls in which a grinding is carried out by impact against steel balls contained in a tubular casing arranged so as to rotate about a horizontal axis under the action of a motor drive. In the crusher 6, water supplied by a supply unit 7 is added to said material. The material and the water are in a constant relationship with one another. For this purpose, continuous weighing is carried out on the conveyor 5 so as to bring a constant quantity of material The grinding in the crusher 6 results in the formation of a sludge having characteristics of grain size and density which

  largely correspond to the desired values.

  The sludge is gradually discharged into a tank 8 from which a pump 9 delivers the material to a sorter 10, for example a filter, which separates the coarse part

  mud The mud treated in this way is transported by llinter-

  medial of a conduit 11, up to 3 a 12 L storage and homogenization device, the separated part is on the contrary returned

  to the crusher 6 via a conduit 13.

  A device 14 is provided along the mud return pipe, which extends from the tank 8 to the filter 31, i L

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  used to measure the ratio between the solid part and the liquid part of the mud The device 14, which may include a hydrometer, controls an additional source 14 of power

in water from the crusher.

  The installation described above works as follows. The solid material transported on the conveyor 5 and the water supplied by the source 7 are introduced into the crusher 6 in a mutual relationship which corresponds to the maximum throughput of the crusher, regardless of any consideration in relation to the subsequent stages of homogenization in the 12 A device

  the outlet of the crusher, the mud has a density which provides an in-

  direct indication of the instantaneous performance of the Le crusher

  returning the mud to the filter 10 results in the recovery of

  immediate sludge with granular characteristics

  metrics required The coarse and substantially dry particles which, after separation by the filter 10, are returned to the crusher, causing a change in the overall proportion of material relative to the water, so that the mud leaving

  has a density greater than the input value.

  The device 14, upon detection of this difference

  density, controls the water source 15, which supplies an additional quantity of water until the desired proportion

recovers in the outgoing mud.

  The constant nature of this ratio allows the crusher 6 to operate at all times with maximum output with regard to output production and the properties of the sludge. The selection made in the filter 10 produces only recycling in the crusher of the material that deviates from the

  imposed grain size As a result, it becomes possible to

  hold a mud in which the solid part, such as that

  which comes out of the mill when the desired characteristics are reached

  rees, is not subjected to another grinding This also allows to obtain a final product whose particle size varies in a narrow range, which results, on the one hand, from the fact that material which prevents already in this size range to be subjected to prolonged grinding and, secondly, by the absence of a residue In this way, we can better manufacture

  articles with a more homogeneous structure.

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  The S ockac apparatus -: t d & homogenisation 12 can

  be of any known type a} proori to the final product to be obtained.

  When you want to get an end product in the form of a

  dre, the device includes Je N device 12 a, consisting for example of one or p slt: -rva 2 with suction or centrifugal separators, pa e ee: ssnsibly 1 l percentage of water contained in the hbou out of device 2 a, the sludge then passes through a tcmis zu cl ssique where O the eliaination of water is almost emageIus '' e that a powder having the desired properties sct cbtenue, According to a characteristic 6: the present invention, to reduce the percentage '-au "on w:, read filters of the type with mechanical action that e-zcess try no ilaportante supply of energy (heat) for their ontionne tl 5 Of course, the invention is not limited to the embodiments described above, which can be the subject of

  Numerous variants Thus, the method of carrying out the installation

  lation, which has been represented in FIG. 2, ensures the separation

  tion, from the base material, of the component having the necessary characteristics: bone particle size For this purpose, the material, instead of hearth introduced directly into the crusher 6, is previously disaggregated in a disaggregation device 16 or a other continuous mill operating by gravity and with

  balls, with addition of water supplied by the source 7.

  A sorting filter 17 (or a hydrocyclone) ensures the separation from the lance resulting from a sludge already having the desired particle size characteristics, this sludge being transferred via a conduit 18 directly into the apparatus for homogenization and storage 12 The remaining solid part is sent to the crusher 6 The installation in FIG. 2 also reduces the particle size range of the

final product.

  Figure 3 shows schematically another embodiment which, by oc_-psraison in the first mode, uses a single filter 19 which receives ià 'both the mud from the tank (8) and that from a disaggregation device 16, this which represents a construction mplification, although

  the filter must obviously have a larger capacity.

  To allow a variation in the level of the mud in the crusher 6, two boxes 20, 21 are provided (FIG. 4)

-6 22 517 590

  placed in superimposed relation to the input and to the

  outlet of the mill, with interposition of seals.

  The invention provides for the use of an auto control

  level of material in optimal conditions of operation of the mill For this purpose, a special control is provided which ensures, in accordance with the level of sludge in the mill, the control of the flow rates of material to be ground and of water. control may include, for example, speed motors

  variable to drive extractors 3, 4.

  In accordance with another embodiment of the

  vention, the two water supply units 7, 15 can be combined in the form of a single unit controlled by the

device 14.

Claims (11)

  1 Process for the preparation of a ceramic material 1 in particular a mixture for the manufacture of tiles characterized by the fact that it comprises: also the steps consisting in grinding in a grinder (; at continuous cycle a mixture of water and of a solid ceramic material of coarse grain size, until a sludge having the characteristics of grain size and   of ratio solid part J, / liquid part approaching the   their desired, to recycle the mud in a sorter (10) in a way E   to separate from the mud a mallow having a grain size exceeding   sant a pre-adjusted limit value, to reintroduce the separated material into the crusher (6) while transporting the sludge to a homogenization and storage device (12)> to measure said ratio in said sludge and to order food in   water from the boiler according to the measured value of said ratio.   2 Method according to claim 1, characterized in that it also includes the steps consisting in preparing: a mixture of ceramic material and water to pass said mixture through a sorting filter (10) to prepare a slurry,   to discharge the sludge d directly into the homogenization apparatus   tion (12) and grinding the remaining part of said mixture.   3 Method according to claim 1, characterized in that it comprises another step consisting in discharging into the filter (10) also the sludge from the step of grinding.   4 Installation for the implementation of the method according to claim i, characterized in that it comprises a continuous cycle mill (6) for grinding a mixture of water and solid ceramic material until one obtains mud with density and granular characteristics   metry approaching the desired values, at least a reservation   see mud (8) to receive the mud from the crusher (6), a pump (9) to pump said mud from the container (8) into a sorter (10) ag Issant so as to separate from the mud a material having a particle size exceeding a preset limit value, means for transporting said separated material to the crusher (6) and for transporting the sludge to a homogenization and storage apparatus (12) and to a device for measuring the ratio (14) between the solid part and   the liquid part of the mud, arranged to control the supply of 251 7590   water ration of said crusher (6) in order to adjust the ratio water / ceramic material.   Installation according to claim 4, characterized in that it comprises a disaggregation device (16) for forming a mixture of ceramic material and water and to which   is associated a sorting filter (17) connected to the homo-apparatus   generation (12) and to the crusher (6) to transport in these   apparatus the mud and respectively the separated matter.   6 Installation according to claim 5, characterized in that it comprises instead of said disaggregation device (16) a continuous ball mill operating by gravity.   7 Installation according to any of the claims   tions 4 and 6, characterized in that said mill (6) comprises two boxes (20, 21) superimposed in a sealed manner on the inlet port and the outlet port with interposition seals.   8 Installation according to any of the claims   tions 4, 5 and 7, characterized in that the homo-   generation and storage (12) includes an action device   mechanical to reduce the percentage of water in the mud.   9 Installation according to claim 8, characterized in that said device comprises one or more filters   with suction or centrifugal separators (17).   10 Installation according to any of the claims   cations 4 to 9, characterized in that it comprises a dis-   automatic control positive (3, 4) to control the level mud in said crusher.   11 Installation according to claim 10, characterized   by the fact that said control device (3, 4) controls the   the material to be ground and water. -8-