WO1994007658A1 - Blasting agent and a process for removing coatings - Google Patents

Blasting agent and a process for removing coatings Download PDF

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Publication number
WO1994007658A1
WO1994007658A1 PCT/NO1993/000137 NO9300137W WO9407658A1 WO 1994007658 A1 WO1994007658 A1 WO 1994007658A1 NO 9300137 W NO9300137 W NO 9300137W WO 9407658 A1 WO9407658 A1 WO 9407658A1
Authority
WO
WIPO (PCT)
Prior art keywords
blasting
blasting agent
agent
water
sulphate
Prior art date
Application number
PCT/NO1993/000137
Other languages
French (fr)
Inventor
Udo Müller
Oddbjørn Steen LARSEN
Original Assignee
Norsk Hydro A.S.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Norsk Hydro A.S. filed Critical Norsk Hydro A.S.
Priority to AU51196/93A priority Critical patent/AU5119693A/en
Publication of WO1994007658A1 publication Critical patent/WO1994007658A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
    • B24C1/08—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for polishing surfaces, e.g. smoothing a surface by making use of liquid-borne abrasives
    • B24C1/086—Descaling; Removing coating films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C11/00—Selection of abrasive materials or additives for abrasive blasts

Definitions

  • the present invention relates to a blasting agent comprising a water-insoluble compound and a process for removing coatings, like paints, oxides, scales and the like from metal, alloys, composites and similar coating substrates by means of blasting media.
  • Sand blasting and other abrasive techniques are quite applicable on hard, durable substrate like granite or hard steel, but requires special arrangements to meet the specification related to environment and working conditions.
  • the main object of the present invention was to select blasting agents for cleaning and removing coatings where the agents also should be environmentally acceptable and not possess the limitations and disadvantages of known agents.
  • Another object was to arrive at an improved process for cleaning substrate without damaging, mechanically or chemically, the substrate surface.
  • the inventors were first of all looking for those applicable for removing coatings without damaging the surface of the substrate. It should also be possible to clean completely structures and equipment having complex geometrical configurations such as valves, bridges etc. having parts which were difficult to arrive at with the cleaning equipment or blasting jets. After having cleaned the substrate it should be easy to remove the cleaning agent together with the removed coating and the cleaning agent itself should be environmentally acceptable.
  • CaC0 3 is a precipitate or more precisely an agglomerate of small par ⁇ ticles.
  • the agglomerates were found to be predominantly of spherical shape and having a particle size range of 10-200 ⁇ m, the main fraction being in the range 40-80 ⁇ m.
  • the Mohs hardness of these agglomerates was in the same range as for dolomite, but in spite of that they proved to be far less damaging to the substrate surface when used as blasting agent.
  • the cleaning effect was surprisingly similar to that of crushed dolomite. The reason for this is not quite clear.
  • One possible explanation could be that the spherical shape of the particles results in less scratching of the surface.
  • Another explanation might be that the agglomerates partly disintegrate during the treatment and are less rough on the surface as it thereby is treated with rather small particles also.
  • Precipitated water-insoluble carbonates or mixtures thereof can easily be produced with various known methods. Also other types of precipitated water-insoluble carbonates than the so-called convertation lime were tested and found equally applicable as blasting agent.
  • the caking properties and flow characteristics of the precipi ⁇ tated carbonates were also tested and compared to those of sodium bicarbonate. These tests proved that the precipitated carbonates were free-flowing and no special anticaking agent was necessary for the conditions in question. This new blasting agent could easily be removed by flushing with water after treatment for removing the coating from the substrate.
  • the additional agent should be of a more crystalline nature and alkali sulphate, and/or magnesium sulphate were found to be suitable for this purpose. Magnesium sulphate in the form of kieserite was found to be particularly useful. The amount of the sulphate agent should not be too high as the sulphate tends to absorb water which may result in plugging of valves of the blasting equipment.
  • Applicable working pressures were found to be in the range of 25- 800 kPa, preferably 300-400 kPa.
  • the amount of agent should be in the range of 0.5-5 kg/min. from a 6 mm blasting nozzle, depending on the type of coating to be removed and the substrate. Blasting nozzles of 6-11 mm will be applicable.
  • the blasting media comprising a slurry of 200-1000 g/1 of particles in water.
  • the agent's particle size and its distribution were not found to be critical. For difficult coatings like rust it was preferred to use relatively large particles and high blasting pressure. The limitations were mainly in the blasting equipment, especially the nozzles, used.
  • the particle size should preferably be below 500 ⁇ m, preferably below lOO ⁇ m. Most advantageous particles are substantially spherical in shape and being agglomerates of particles of a size of less than 5 ⁇ m.
  • Figs. la,b show SEM pictures of unpurified crushed dolomite.
  • Figs. 2a,b show SEM pictures of unpurified precipi ⁇ tated CaC0 3 .
  • Figs, la and lb show SEM (scanning electromicroscope) pictures of crushed dolomite in which 1 cm represents lOO ⁇ m and l ⁇ m, respectively. The crystalline structure of the dolomite particles can clearly be seen from these SEM pictures, especially from Fig. lb.
  • Figs. 2a and 2b show similar SEM pictures of precipitated CaC0 3 , derived from the conversion of calcium nitrate from a nitrophos- phate process.
  • Fig. 2a 1 cm corresponds to lOO ⁇ m
  • Fig. 2b 1 cm corresponds to lO ⁇ m.
  • the particle shown in Fig. 2b is about 60 ⁇ m, and it can clearly be seen that it is an agglomerate of tiny particles. Further, the predominantly spherical shape of the precipitated calcium carbonate is clearly demonstrated by these pictures.
  • a galvanized metal sheet and a substrate of brass were treated by blasting with precipitated calcium CaC0 3 suspended in water.
  • the treatment was performed at a blasting pressure of 340 kPa and a water pressure of 4000 kPa.
  • the average particle size of the CaC0 3 particles was 60 ⁇ m and the Mohs hardness was 3.0.
  • the smoothness i.e. the average depth (Ra-value)
  • the Ra-value (DIN 4768/1) is the arithmetical mean for the depth of the grooves and is an expression for the roughness of the surface.
  • High Ra-values means deep grooves.
  • a painted metal sheet having a paint layer of 40 ⁇ m was treated as described in Example 1.
  • the paint layer was removed completely. No damage of the metal surface could be observed.
  • This example shows removal of graphite paint from stone (Mexi- stone) under the same conditions as in Example 1, except that the blasting pressure was 260 kPa.
  • This example shows removal of graphite paint from glazed roof tiles.
  • the treatment conditions were as stated in Example 1, except that the water pressure now was 4500 kPa.
  • the graphite was completely removed without any damage to the substrate surface.
  • This example shows removal of painting from a steel surface.
  • the treatment conditions were as stated in Example 1 except for the applied blasting agent.
  • the blasting agent consisted of 75 weight% CaC0 3 and 25 weight% magnesium sulphate in the form of kieserite having an average particle size of 300 ⁇ m and a Mohs hardness of 3 1/2.
  • the paint coating was easily stripped off and removed from the steel surface together with the blasting agent by flashing with a water jet leaving a very smooth surface on the substrate. No damage of the substrate surface due to the treatment was observed.
  • the investigations and examples disclosed in the preceding description show that the inventors have succeeded in providing an improved process by applying a new blasting agent.
  • the process is most flexible with regard to removing various types of coatings from substrates having hardness from that of steel to wood without causing damage to the substrate surface.
  • the blasting agent can easily be removed by flushing with water. The person carrying out the cleaning process is not exposed to any harm and the agent is acceptable from an environmental point of view.
  • the agent is also available in desired qualities, particle size etc. and is relatively cheap.

Abstract

The present invention relates to a blasting agent for removing coatings like paint, oxides, scales and the like from metals, alloys, composites and similar substrates, and a process for removing said coatings. The blasting agent comprises a precipitate or agglomerate thereof of water-insoluble calcium carbonate, magnesium carbonate or mixtures thereof and 0-30 weight % alkali sulphate and/or magnesium sulphate. Preferred blasting agent is precipitated calcium carbonate or agglomerates thereof having particle size of 10-200 νm and consisting of precipitated CaCO3 particles larger than 5 νm. For hard surfaces 20-30 weight % of the blasting agent should comprise the sulphate agent. The process is performed at a blasting pressure of 50-800 kPa, preferably 200-400 kPa.

Description

Blasting agent and a process for removing coatings
The present invention relates to a blasting agent comprising a water-insoluble compound and a process for removing coatings, like paints, oxides, scales and the like from metal, alloys, composites and similar coating substrates by means of blasting media.
Cleaning of the surfaces of various types of equipment and structures is often desirable. Numerous processes and cleaning agents are known in the art. Choice of process and agent will to a great extent depend on the coating to be removed, but also on the substrate. Working conditions and environmental effects of the process and agent used are becoming increasingly important factors when selecting the optimal technique.
Sand blasting and other abrasive techniques are quite applicable on hard, durable substrate like granite or hard steel, but requires special arrangements to meet the specification related to environment and working conditions.
Less hard and durable substrate like aluminium, wood, composites etc. require processes and cleaning agents which do not cause mechanical or chemical damage to the surface of the substrate.
In Journal of Protective Coatings & Linings, Oct. 1990, pages 50- 58 Janet Rex gives "an evaluation of several techniques including sand blasting, wet blasting with soluble abrasives, cryogenic cleaning with dry ice". Known water-soluble abrasives are considered to be best suited for maintenance painting rather than new constructions. Bicarbonate of soda is for instance not considered applicable for removal of scale or rust.
In the patent application WO 90/11163 there is described a cleaning process comprising application of water-soluble bicarbonate particles having particle sizes within the range of 10-500μm, in a mixture with 0.2-3% by weight of the carbonate of a hydrofobic silica flow/anticaking agent. Though this process seems to be suitable for removal of paints without causing grooves or profiles in the substrate surface, it is limited to application of particles smaller than 500μm and an anticaking agent which is insoluble in water. A further disadvantage of this process is the risk for stress corrosion on carbon steel treated with carbonates.
It is further known to use water-insoluble agents like crushed dolomite having particle size in the range of l-100μm or larger. This has especially been used for cleaning substrates or structures of natural stone such as granite or marble. However, this agent having a Mohs hardness of about 3.0 tends to leave profiles or grooves in the treated surface. Even more dominant was this when the surface to be treated was softer as in the case of wood substrates.
The main object of the present invention was to select blasting agents for cleaning and removing coatings where the agents also should be environmentally acceptable and not possess the limitations and disadvantages of known agents.
Another object was to arrive at an improved process for cleaning substrate without damaging, mechanically or chemically, the substrate surface. In the evaluation of possible new processes and agents for removing coatings, the inventors were first of all looking for those applicable for removing coatings without damaging the surface of the substrate. It should also be possible to clean completely structures and equipment having complex geometrical configurations such as valves, bridges etc. having parts which were difficult to arrive at with the cleaning equipment or blasting jets. After having cleaned the substrate it should be easy to remove the cleaning agent together with the removed coating and the cleaning agent itself should be environmentally acceptable.
In view of the above considerations it was decided to investigate further the processes based on application of water-insoluble agents which in spite of being insoluble in water could clean the substrate without damaging its surface.
Various possible compounds, including carbonates, were evaluated and tested. Though water-insoluble carbonates like dolomite have been found to possess some disadvantages, such carbonates were further investigated because of their availability and low price. Closer studies of such particles revealed that their structure was predominantly crystalline. This fact could explain its tendency to leave profiles or grooves in the treated surface. The inventors then started looking for other types of carbonates, and during this search they obtained precipitated calcium carbonates of various particle size and qualities and started testing these as blasting agents. One such precipitate is a by-product from the nitrophosphate fertilizer process. Calcium nitrate from this process is treated with ammonia and carbon dioxide, whereby the calcium nitrate is converted into ammonium nitrate and calcium carbonate, also called convertation lime. Thus produced CaC03 is a precipitate or more precisely an agglomerate of small par¬ ticles. The agglomerates were found to be predominantly of spherical shape and having a particle size range of 10-200μm, the main fraction being in the range 40-80μm. The Mohs hardness of these agglomerates was in the same range as for dolomite, but in spite of that they proved to be far less damaging to the substrate surface when used as blasting agent. The cleaning effect, however, was surprisingly similar to that of crushed dolomite. The reason for this is not quite clear. One possible explanation could be that the spherical shape of the particles results in less scratching of the surface. Another explanation might be that the agglomerates partly disintegrate during the treatment and are less rough on the surface as it thereby is treated with rather small particles also.
Precipitated water-insoluble carbonates or mixtures thereof can easily be produced with various known methods. Also other types of precipitated water-insoluble carbonates than the so-called convertation lime were tested and found equally applicable as blasting agent.
The caking properties and flow characteristics of the precipi¬ tated carbonates were also tested and compared to those of sodium bicarbonate. These tests proved that the precipitated carbonates were free-flowing and no special anticaking agent was necessary for the conditions in question. This new blasting agent could easily be removed by flushing with water after treatment for removing the coating from the substrate.
Though the experience with this new blasting agent was most positive, it was found that for rather hard surfaces and coatings that were difficult to remove the results of the treatment were not quite satisfactory. In these cases it was found that excellent results could be achieved and the advantages of the precipitated blasting agent retained if minor amounts of another blasting agent were mixed with the precipitated agent. The additional agent should be of a more crystalline nature and alkali sulphate, and/or magnesium sulphate were found to be suitable for this purpose. Magnesium sulphate in the form of kieserite was found to be particularly useful. The amount of the sulphate agent should not be too high as the sulphate tends to absorb water which may result in plugging of valves of the blasting equipment. Removal of the agent subsequent to the treatment could also be a problem if too much of the sulphate was applied. Up to 30 weight%, preferably 20-30 weight%, proved to be optimal amounts of the sulphate agent together with the precipi¬ tated agent. Then the precipitated agent seemed to neutralize the negative effects of the sulphate agent and the total result of the blasting treatment was most satisfactory.
Applicable working pressures were found to be in the range of 25- 800 kPa, preferably 300-400 kPa. The amount of agent should be in the range of 0.5-5 kg/min. from a 6 mm blasting nozzle, depending on the type of coating to be removed and the substrate. Blasting nozzles of 6-11 mm will be applicable. The blasting media comprising a slurry of 200-1000 g/1 of particles in water. The agent's particle size and its distribution were not found to be critical. For difficult coatings like rust it was preferred to use relatively large particles and high blasting pressure. The limitations were mainly in the blasting equipment, especially the nozzles, used. The particle size should preferably be below 500μm, preferably below lOOμm. Most advantageous particles are substantially spherical in shape and being agglomerates of particles of a size of less than 5μm.
The scope of the invention is as defined in the attached claims.
The invention will be further explained in connection with the description of the figures and the following examples.
Figs. la,b show SEM pictures of unpurified crushed dolomite.
Figs. 2a,b show SEM pictures of unpurified precipi¬ tated CaC03. Figs, la and lb show SEM (scanning electromicroscope) pictures of crushed dolomite in which 1 cm represents lOOμm and lμm, respectively. The crystalline structure of the dolomite particles can clearly be seen from these SEM pictures, especially from Fig. lb.
Figs. 2a and 2b show similar SEM pictures of precipitated CaC03, derived from the conversion of calcium nitrate from a nitrophos- phate process. In Fig. 2a 1 cm corresponds to lOOμm, and in Fig. 2b 1 cm corresponds to lOμm. The particle shown in Fig. 2b is about 60μm, and it can clearly be seen that it is an agglomerate of tiny particles. Further, the predominantly spherical shape of the precipitated calcium carbonate is clearly demonstrated by these pictures.
Example 1
A galvanized metal sheet and a substrate of brass were treated by blasting with precipitated calcium CaC03 suspended in water. The treatment was performed at a blasting pressure of 340 kPa and a water pressure of 4000 kPa. The average particle size of the CaC03 particles was 60μm and the Mohs hardness was 3.0.
The smoothness, i.e. the average depth (Ra-value) , of ripples or grooves in the substrate surface was measured before and after treatment. The Ra-value (DIN 4768/1) is the arithmetical mean for the depth of the grooves and is an expression for the roughness of the surface. High Ra-values means deep grooves.
Before treatment the surface of the two substrates had Ra = 0.01- 0.02μm and after treatment corresponding measurement showed Ra = 1.3-1.5μm. Accordingly, the treatment did not result in any damage of the substrate surfaces. Example 2
A painted metal sheet having a paint layer of 40μm was treated as described in Example 1.
The paint layer was removed completely. No damage of the metal surface could be observed.
Example 3
This example shows removal of graphite paint from stone (Mexi- stone) under the same conditions as in Example 1, except that the blasting pressure was 260 kPa.
After treatment with the blasting agent the stone surface was flushed with water and no remaining paint could be observed, and the stone surface was not in any way damaged.
Example 4
This example shows removal of graphite paint from glazed roof tiles. The treatment conditions were as stated in Example 1, except that the water pressure now was 4500 kPa.
The graphite was completely removed without any damage to the substrate surface.
Example 5
This example shows removal of painting from a steel surface. The treatment conditions were as stated in Example 1 except for the applied blasting agent.
In this example the blasting agent consisted of 75 weight% CaC03 and 25 weight% magnesium sulphate in the form of kieserite having an average particle size of 300 μm and a Mohs hardness of 3 1/2. The paint coating was easily stripped off and removed from the steel surface together with the blasting agent by flashing with a water jet leaving a very smooth surface on the substrate. No damage of the substrate surface due to the treatment was observed.
The investigations and examples disclosed in the preceding description show that the inventors have succeeded in providing an improved process by applying a new blasting agent. The process is most flexible with regard to removing various types of coatings from substrates having hardness from that of steel to wood without causing damage to the substrate surface. The blasting agent can easily be removed by flushing with water. The person carrying out the cleaning process is not exposed to any harm and the agent is acceptable from an environmental point of view. The agent is also available in desired qualities, particle size etc. and is relatively cheap.

Claims

:HIClaims
1. Blasting agent having particle size less than 500μm for removing coatings like paint, oxides, scales and the like from metals, alloys, composites and similar substrates, c h a r a c t e r i z e d i n t h a t the blasting agent comprises a precipitate or agglomerate thereof of water-insoluble calcium carbonate, magnesium carbonate or mixtures thereof and 0-30 weight% of particles of alkali sulphate and/or magnesium sulphate.
2. Blasting agent according to claim 1, c h a r a c t e r i z e d i n t h a t it consists of precipitated calcium carbonate or agg¬ lomerates thereof.
3. Blasting agent according to claim 1, c h a r a c t e r i z e d i n t h a t the agent comprises agglomerates having particle size of 10-2OOμm and consisting of precipitated CaC03 particles larger than 5μm.
4. Blasting agent according to claim 1, c a r a c t e r i s e d i n t h' a t the blasting agent is a mixture of 80-70 weight% of a precipitate or agglomerate thereof of water-insoluble calcium carbonate, magnesium carbonate or their mixture and 20-30 weight% alkali sulphate and/or magnesium sul¬ phate.
5 Blasting agent according to claim 1, c h a r a c t e r i z e d i n t h a t the blasting agent comprises 20-30 weight% magnesium sulphate in the form of kieserite. 6. Process for removing coatings like paint, oxides, scales and the like from metals, alloys, composites and similar substrates comprising exposing such coatings to blasting treatment with air stream containing at least one water- insoluble blasting agent suspended in water, c h a r a c t e r i z e d i n t h a t it is applied an agent being a precipitate or agglomerate thereof of water-insoluble calcium carbonate, magnesium carbonate or mixtures thereof, and that the process if performed at a blasting pressure of 50-800 kPa, prefer¬ ably 200-400 kPa.
PCT/NO1993/000137 1992-09-25 1993-09-17 Blasting agent and a process for removing coatings WO1994007658A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU51196/93A AU5119693A (en) 1992-09-25 1993-09-17 Blasting agent and a process for removing coatings

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO923725 1992-09-25
NO923725A NO175807C (en) 1992-09-25 1992-09-25 Method of coating removal and blowing agent for coating removal

Publications (1)

Publication Number Publication Date
WO1994007658A1 true WO1994007658A1 (en) 1994-04-14

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2325000A (en) * 1997-05-09 1998-11-11 Stephen William Rudman Blast cleaning using calcium carbonate
WO1998051901A1 (en) * 1997-05-14 1998-11-19 Sofitech N.V. Conduit cleaning material and process
WO2003061908A1 (en) * 2002-01-24 2003-07-31 Exa Sa A process for treating a surface
WO2004084851A2 (en) * 2003-03-24 2004-10-07 Exa Sa A treatment composition
EP1607373A1 (en) * 2003-02-27 2005-12-21 Okutama Kogyo Co., Ltd. Spherical calcium carbonate and method for production thereof
FR2875719A1 (en) * 2004-09-28 2006-03-31 Appia Modification of layer of asphalt comprises pressurised spraying of suspension of abrasive particles in liquid suspension
EP1647363A1 (en) * 1998-12-04 2006-04-19 Farrow System Limited Method for removing surface coatings
EP2113339A1 (en) 2008-04-30 2009-11-04 Omya Development AG Alkaline earth carbonate containing mineral for surface cleaning
EP3045503A1 (en) 2015-01-15 2016-07-20 Omya International AG Surface-treated calcium carbonate with improved stability in environments with a pH of 4.5 to 7

Citations (4)

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Publication number Priority date Publication date Assignee Title
NL91624C (en) * 1900-01-01
SE371668B (en) * 1973-03-30 1974-11-25 Producem Ab
EP0374291A1 (en) * 1988-12-21 1990-06-27 JOS Verwaltungs-GmbH & Co. Gesellschaft für Reinigungsverfahren KG Method of cleaning surfaces, especially delicate surfaces
WO1990011163A2 (en) * 1989-03-14 1990-10-04 Church & Dwight Co., Inc. Process for removing coatings from sensitive substrates, and blasting media useful therein

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL91624C (en) * 1900-01-01
SE371668B (en) * 1973-03-30 1974-11-25 Producem Ab
EP0374291A1 (en) * 1988-12-21 1990-06-27 JOS Verwaltungs-GmbH & Co. Gesellschaft für Reinigungsverfahren KG Method of cleaning surfaces, especially delicate surfaces
WO1990011163A2 (en) * 1989-03-14 1990-10-04 Church & Dwight Co., Inc. Process for removing coatings from sensitive substrates, and blasting media useful therein

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2325000A (en) * 1997-05-09 1998-11-11 Stephen William Rudman Blast cleaning using calcium carbonate
GB2325000B (en) * 1997-05-09 2000-12-06 Stephen William Rudman Blast cleaning
WO1998051901A1 (en) * 1997-05-14 1998-11-19 Sofitech N.V. Conduit cleaning material and process
US6032741A (en) * 1997-05-14 2000-03-07 Schlumberger Technology Corporation Abrasives for well cleaning
GB2325260B (en) * 1997-05-14 2000-06-07 Sofitech Nv Abrasives for well cleaning
AU751473B2 (en) * 1997-05-14 2002-08-15 Schlumberger Technology B.V. Conduit cleaning material and process
EP1647363A1 (en) * 1998-12-04 2006-04-19 Farrow System Limited Method for removing surface coatings
WO2003061908A1 (en) * 2002-01-24 2003-07-31 Exa Sa A process for treating a surface
EP1666203A1 (en) * 2002-01-24 2006-06-07 Exa SA A process for removing a coating from a surface
EP1738872A1 (en) * 2002-01-24 2007-01-03 Exa SA Agent for exfoliating skin
EP1607373A1 (en) * 2003-02-27 2005-12-21 Okutama Kogyo Co., Ltd. Spherical calcium carbonate and method for production thereof
EP1607373A4 (en) * 2003-02-27 2011-10-26 Okutama Kogyo Co Ltd Spherical calcium carbonate and method for production thereof
WO2004084851A3 (en) * 2003-03-24 2004-11-11 Exa Sa A treatment composition
WO2004084851A2 (en) * 2003-03-24 2004-10-07 Exa Sa A treatment composition
FR2875719A1 (en) * 2004-09-28 2006-03-31 Appia Modification of layer of asphalt comprises pressurised spraying of suspension of abrasive particles in liquid suspension
WO2009133173A1 (en) * 2008-04-30 2009-11-05 Omya Development Ag Alkaline earth carbonate containing mineral for surface cleaning
EP2113339A1 (en) 2008-04-30 2009-11-04 Omya Development AG Alkaline earth carbonate containing mineral for surface cleaning
RU2498891C2 (en) * 2008-04-30 2013-11-20 Омиа Девелопмент Аг Mineral bearing alkaline metal carbonate for surface cleaning
US8597077B2 (en) 2008-04-30 2013-12-03 Omya International Ag Alkaline earth carbonate containing mineral for surface cleaning
CN102026776B (en) * 2008-04-30 2015-11-25 Omya国际股份公司 For the mineral comprising alkaline earth metal carbonate of removing surface
EP3045503A1 (en) 2015-01-15 2016-07-20 Omya International AG Surface-treated calcium carbonate with improved stability in environments with a pH of 4.5 to 7
WO2016113285A1 (en) 2015-01-15 2016-07-21 Omya International Ag Surface-treated calcium carbonate with improved stability in environments with a ph of 4.5 to 7

Also Published As

Publication number Publication date
NO175807C (en) 1994-12-14
NO923725D0 (en) 1992-09-25
NO923725L (en) 1994-03-28
NO175807B (en) 1994-09-05
AU5119693A (en) 1994-04-26

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