US2863739A - Process for the continuous production of crystalline substances - Google Patents

Process for the continuous production of crystalline substances Download PDF

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Publication number
US2863739A
US2863739A US521519A US52151955A US2863739A US 2863739 A US2863739 A US 2863739A US 521519 A US521519 A US 521519A US 52151955 A US52151955 A US 52151955A US 2863739 A US2863739 A US 2863739A
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United States
Prior art keywords
kneading
melt
crystallization
continuously
continuous production
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US521519A
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English (en)
Inventor
Erbe Friedrich
Maikowski Michael Alexander
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Hoechst AG
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Hoechst AG
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Publication date
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/32—Non-reciprocal transmission devices
    • H01P1/38—Circulators
    • H01P1/393—Circulators using Faraday rotators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0004—Crystallisation cooling by heat exchange
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0036—Crystallisation on to a bed of product crystals; Seeding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
    • B01J2/10—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic in stationary drums or troughs, provided with kneading or mixing appliances
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/02—Preparation of sulfur; Purification
    • C01B17/0205—Separation of sulfur from liquids, e.g. by coalescence
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/02—Preparation of sulfur; Purification
    • C01B17/0216—Solidification or cooling of liquid sulfur
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/02—Preparation of sulfur; Purification
    • C01B17/0237—Converting into particles, e.g. by granulation, milling
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/30—Alkali metal phosphates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/20—Silicates
    • C01B33/32—Alkali metal silicates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
    • C01C1/00—Ammonia; Compounds thereof
    • C01C1/24—Sulfates of ammonium
    • C01C1/248—Preventing coalescing or controlling form or size of the crystals
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/38—Separation; Purification; Stabilisation; Use of additives
    • C07C17/392—Separation; Purification; Stabilisation; Use of additives by crystallisation; Purification or separation of the crystals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
    • G01S7/034—Duplexers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps
    • H01J25/36—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field
    • H01J25/38—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field the forward travelling wave being utilised

Definitions

  • IIIIIIIIII I N VEN TORS FR/EDR/CH ERBE N/ CHAEL AZEXANDEA ///4/KOW5/(/ BY W NDWJMM ATTORNEYS.
  • the present invention relates to a process for the continuous production of crystalline substances.
  • the present invention relates to a process for the continuous production of crystalline substances.
  • I For the continuous production of crystalline substances in a powdery or granulated form from crystallizable melts two different methods have been developed, i.
  • the atomization in an air current involves the drawback that relatively large rooms are required to enable the atomized drops to pass a sufiiciently long way for depositing.
  • the solidification on a scraping drum first yields the desired product in the form of flakes or scales, so that it must further be comminuted by a special operation when a powdery or finely granulated product is desired.
  • Substances having a low speed of crystallization for example the hydrates of sodium meta-silicate containing at most 9 mols of water per 1 mol of N21 SiO can, however, be processed by these two methods only with difficulty, if at all.
  • the atomization carried out, While cooling, does not succeed since the rate of fall of the drops, even when prolonged by suitable measures, is smaller than the time required for crystallization.
  • the second method referred to, i. e. the solidification on a scraping drum may, in principle, be used; however, in view of the necessary long duration of the drops on the cooling surfaces the capacity of such apparatus is small or a disproportionately large apparatus is required to attain the desired effect.
  • the melts have been poured out into crystallizing containers, pans or dishes and allowed to solidify therein, an operation which takes many hours or even days.
  • the solidified melt has then been removed in the form of sheets, blocks or pieces which have then been comminuted to the desired fineness by means of a crusher or a mill.
  • This process involves the drawback of requiring a great expenditure of time and energy and manpower.
  • crystalline material of powdery or granulated form can be obtained continuously from crystallizable melts in a simple manner and by one single operation by kneading the melt with an' excess of already crystalline material of the same composition and formed by this process and, simultaneously, moving forward during the kneading process the entire material in Patented Dec. 9, 1958 a continuous flow.
  • the heat of crystallization evolved during the operation may be carried off the crystallizing material. It is of advantage to conduct this operation in a manner such that the heat evolved is dissipated to the walls of the apparatus, in which the process is effected.
  • the process of this invention is advantageously conducted in such a manner that the material is mixed only in small zones, while being conveyed and, simultaneously, kneaded. It is likewise advantageous to operate in a manner such that an intimate mixing takes place in every section vertical to the conveying direction. Every constituent of substance passing through the apparatus is mixed, advantageously, only with such constituents of substance as, compared with the duration of the first constituent in the apparatus, have been introduced within a short time before or after the introduction of the first mentioned constituent.
  • the process of this invention can be used for crystallizing any kinds of crystallizable melts, for instance melts of inorganic or organic substances.
  • the process according to this invention can suitably be used for treating rapidly crystallizing substances and can also be used with special advantage for treating slowly and even very slowly crystallizing substances part of which could hitherto not satisfactorily be processed for industrial purposes.
  • substances suitable for being processed by the process of this invention there may be named, tri-sodium phosphate, p-dichloro-benzene, sodium meta-silicate-9- hydrate, sodium meta-sllicate-4-hydrate, sulfur, calcium nitrate, the hydrates of sodium carbonate, or sodium sulfate, or mixtures of washing agents which contain active substances in association with sodium carbonate containing crystal water and/or with sodium sulfate and/or sodium phosphate and/or sodium silicate.
  • the process of this invention can be conducted using any type of apparatus adapted to the specific purposes intended.
  • the melt is introduced into the apparatus at inlet 6, and conveyed by the first spirals and kneaded in the main part of the apparatus with the mixture of melt and the crystals that have already been formed.
  • the ratio of said crystals to the melt increases the more, the more the mixture, while being constantly kneaded, approaches outlet 7.
  • the heat of crystallization and the frictional heat evolved by the kneading process may be dissipated to cooling agents 8 and 9 through the walls of easing 1 or through the walls of shaft 2 which may be tubular, or the heat may be dissipated by means of the walls of casing 1 and the walls of the shaft 2.
  • the product leaves the apparatus in a solid powdery or granulated form at the outlet 7 which may be larger or smaller as shown or even be dispensed with.
  • the process of this invention can be conducted with special advantage using an apparatus with dimensions essentially larger in the conveying direction than in the vertical direction, for example, as large as about to 20 times.
  • the apparatus may have, for example, a casing extended in the conveying direction with a shaft rotating in the longitudinal direction and equipped with kneading elements.
  • the casing may also be equipped with several shafts rotating with the same, a different or a periodically changing speed; the kneading elements, such as endless screws, interrupted screws, wings and teeth may intermesh and clean themselves reciprocally.
  • the rotating movement of the shaft may be combined with to-and-fro motion in the axial direction; the interior of the casing may also be fitted with stationary kneading elements which interact with the movable elements.
  • the proportion of kneading to conveying effect is advantageously selected in this case in such a Way that the kneading effect varies inversely with the crystallization speed of the substance to be crystallized.
  • This may be attained, for example, by changing the form and/or the position of the kneading elements; such regulation, if desired, in association with a regulation of the number of revolutions of the kneading shaft enables to obtain the best output, regardless whether rapidly or slowly crystallizing melts are to be processed.
  • the processing of especially slowly crystallizing substances may be facilitated by leading oiT-the heat of crystallization evolved, at a temperature of maximum crystallization speed, and by taking care to avoid an undercooling below that temperature.
  • melt If the melt is passed continuously through an apparatus operating on these principles and otherwise being provided with any kind of equipment, a steady state is reached, i. e. the melt is constantly supplied at the inlet and the same amount of powdery or granulated solid substance constantly leaves the apparatus at the outlet.
  • the proportion of crystalline substance to melt may remain temporarily constant in every section of the apparatus, whereas it varies locally and increases towards the conveying'direction. Such increase may extend over the entire length of the apparatus or it may be limited to part of the apparatus.
  • the process of this invention may, for example, be conducted as follows: Three zones are arranged, i. e. a first zone in which the melt is cooled to the temperature of crystallization, a second zone containing a mixture of melt and crystals in which mixture the content of solid substance locally increases towards the conveying direction from zero to 100 percent'and, finally, a third zone which serves to give the crystalline mass the desired final temperature and/ or the desired fineness.
  • the first and/ or the third zone may, if desired, be dispensed with.
  • the crystals which have just been formed are constantly mixed with new melt. As seed crystals they favor the crystallization of the fresh melt introduced without it being necessary to reintroduce solid substance into the apparatus.
  • the substance to be processed spontaneously forms a sufficient number of nuclei no crystals need be introduced into the apparatus when putting it into operation; if no nuclei or not enough nuclei are formed a crystalline substance of the same composition alone or in admixture with the melt is once introduced into the apparatus at the beginning of the operation. Thereby the steady state is more rapidly attained at which state agglomerated crystalline material in the end part of the kneader causes the resistance necessary to produce the kneading effect. Generally, it is sufiicient to feed about one fourth to about one half of the kneading device with crystalline substance.
  • the heat exchange between the product within the apparatus and a cooling agent can, advantageously, be effected by dissipating the heat to the walls of the casing.
  • the shaft provided with the kneading element either alone or in combination with the walls of the casing provided said shaft is suitably constructed, for example of tubular construction, enabling the cooling agent to stream through.
  • the cooling agent may be of gaseous nature; air may, for example, be used. It is, however, of advantage to use a liquid cooling agent, for example water, in order to effect a good heat transmission.
  • cooling jacket For conducting the cooling agent, it is often advisable to use an apparatus equipped with a cooling jacket, it being particularly advantageous if said cooling jacket can be subdivided into single zones so that the substance passing through the apparatus may come into contact, on its way, with cooling walls of difierent temperature.
  • a reduction of the length of the first and/or the third zone is thus reached, so that the apparatus can be used more advantageously for its specific purpose, i. e. the kneading of the melt and crystals, and its capacity is increased thereby.
  • Example 1 A melt of trisodium phosphate heated to about C. and containing 10.6 mole of water per 1 mol of Na PO is introduced continuously into a kneading apparatus at a rate of 4.2 kilograms per hour.
  • Said apparatus has a rotating shaft performing simultaneously periodic axial displacements and on which shaft spirals interrupted by interstices are arranged; on the inner side of the casing kneading teeth are arranged which correspond to said interstices.
  • the terminal part of the casing having an internal diameter of 4.7 cm. and the tubular kneading shaft of 35 cm. length are cooled With cooling water of 20 C., and the inlet of the casing is cooled with cooling water of 50 C.
  • the crystalline product continuously leaves the open outlet of the kneading apparatus in the form of a fine powder.
  • Example 2 The kneading apparatus described in Example 1 is continuously fed at a rate of 2.4 kilograms per hour with a melt of p-dichlorobenzene heated to 56 C., all parts of the apparatus that can be cooled being cooled with water of 25 C. p-Dichlorobenzene is produced continuously in the form of a fine powder.
  • Example 3 Into the kneading apparatus described in Example 1 molten sodium-meta-silicate-9-hydrate of 50 C. is introduced continuously at a rate of 4.1 kilograms per hour. The casing and the tubular kneading shaft are cooled with Water of 25 C. At the beginning of the kneading operation about grams of crystallized sodium metasilicate 9-hydrate are once added to the melt; from that time there is only added the melt. At the open outlet of the kneading apparatus crystallized meta-silicate continuously leaves the kneadcr in a powdery or finely granulated form.
  • Example 4 Molten sodium-meta-silicate-4-hydrate of about 80 C. is processed continuously at a rate of 2.7 kilograms per hour under the conditions described in Example 1. The temperatures of the cooling water amount at the inlet of the casing to 50 C., at the terminal part and at the tubular kneading shaft to 40 C. At the beginning of the kneading operation about 50 grams of a mixture of equal parts of melt and already crystalline substance are added; from that time there is only added the melt. The product is obtained continuously in a powdery to granulated form.
  • Example 5 Molten sulfur of 120-130 C. is introduced continuously into the apparatus described in Example 1.
  • the kneading shaft and the part of the casing near the inlet are cooled with water of 50 C., and the terminal part of the casing is cooled with water of 20 C.
  • the output amounts to 3 kilograms per hour.
  • Sulfur is obtained in the form of a fine powder with a small portion of a gritty constituent.
  • the output may be increased to 10 kilograms per hour.
  • a process for the continuous production of crystalline material ranging from powdered to granulated form from crystallizable melts which comprises continuously and intimately kneading the melt with an excess of crystals of said material which have already formed and with the crystals forming, While dissipating the liberated heat of crystallization.
  • a process for the continuous production of crystalline material ranging from powdered to granulated form from crystallizable melts which comprises continuously and intimately intensively kneading the melt with an excess of crystals of said material, whereby the melt is incorporated into said excess of crystallized material by intimate trituration, while dissipating the liberated heat of crystallization.
  • a process for the continuous production of crystalline material in ground form from crystallizable melts which comprises continuously and intimately intensively kneading the melt with an excess of crystals of said material at one zone, simultaneously continuously advancing the kneaded mass to a second zone, the proportion of melt decreasing during said advancing until only dry solid material remains, continuously dissipating the liberated heat of crystallization from said zones, and continuously withdrawing the dry ground crystalline material from said second zone.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Analytical Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Thermal Sciences (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Glanulating (AREA)
US521519A 1954-07-16 1955-07-12 Process for the continuous production of crystalline substances Expired - Lifetime US2863739A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE334298X 1954-07-16

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US2863739A true US2863739A (en) 1958-12-09

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US (1) US2863739A (Direct)
BE (1) BE539879A (Direct)
CH (1) CH334298A (Direct)
FR (1) FR1134127A (Direct)
GB (1) GB812082A (Direct)
NL (1) NL110768C (Direct)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3057677A (en) * 1960-10-06 1962-10-09 Bell Telephone Labor Inc Yttrium and rare earth borates
US3162556A (en) * 1953-01-07 1964-12-22 Hupp Corp Introduction of disturbance points in a cadmium sulfide transistor
WO1985002781A1 (en) * 1983-12-27 1985-07-04 Cheng Sing Wang A fractional solidification process and apparatuses for use therein

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1327743A (en) * 1920-01-13 Process for making powdered or granulated aluminum
US1911860A (en) * 1932-06-09 1933-05-30 Grasselli Chemical Co Granulation of zinc chloride
US1999873A (en) * 1932-06-09 1935-04-30 Grasselli Chemical Co Process of preparing zinc chloride melts for granulation

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1327743A (en) * 1920-01-13 Process for making powdered or granulated aluminum
US1911860A (en) * 1932-06-09 1933-05-30 Grasselli Chemical Co Granulation of zinc chloride
US1999873A (en) * 1932-06-09 1935-04-30 Grasselli Chemical Co Process of preparing zinc chloride melts for granulation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3162556A (en) * 1953-01-07 1964-12-22 Hupp Corp Introduction of disturbance points in a cadmium sulfide transistor
US3057677A (en) * 1960-10-06 1962-10-09 Bell Telephone Labor Inc Yttrium and rare earth borates
WO1985002781A1 (en) * 1983-12-27 1985-07-04 Cheng Sing Wang A fractional solidification process and apparatuses for use therein

Also Published As

Publication number Publication date
GB812082A (en) 1959-04-15
CH334298A (de) 1958-11-30
FR1134127A (fr) 1957-04-08
NL110768C (Direct)
BE539879A (Direct)

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