Process for manufacturing white pigment containing products

Abstract

A process is described for manufacturing white pigment containing products. The white pigment containing products are obtained from at least one white pigment and impurities containing material via froth flotation.

Claims

1. A process for manufacturing white pigment containing products, the process comprising the following steps: a) providing at least one white pigment and impurities containing material; b) providing at least one collector agent selected from the group consisting of compounds of formula (1): ##STR00016## wherein; R.sup.1CO represents a saturated or unsaturated, linear or branched acyl group having from 8 to 24 carbon atoms; R.sup.2 is selected from the group consisting of a 1. Direct bond, 2. a C.sub.1-C.sub.20, linear or branched, saturated or unsaturated hydrocarbon chain optionally substituted by one or more OH group(s), one or more methyl and/or methylene groups, a cycloalkylene group, a cycloalkenylene group and/or an arylene group; R.sup.3 is selected from the group consisting of a hydrocarbyl group having from 8 to 24 carbon atoms or a group of formula R.sup.5O-(AO).sub.w-T-, wherein; R.sup.5 represents a hydrocarbyl group having from 8 to 24 carbon atoms; w is a number within the range from 0 to 20; AO is an alkyleneoxy group having from 2 to 4 carbon atoms; and T represents an alkylene group having from 1 to 6 carbon atoms; R.sup.4 is selected from the group consisting of a hydrocarbyl group or a benzyl group; AO represents an alkyleneoxy group having from 2 to 4 carbon atoms; X represents an anion derived from an alkylating agent R.sup.4X, wherein X represents halogen, sulphate or carbonate; x is a number within the range from 1 to 20; p is a number within the range from 1 to 15; t is 0 or 1; y is 0 or 1; and G represents a group of formula (2); ##STR00017## wherein; B represents an alkyl group having from 1 to 4 carbon atoms or represents a benzyl group; s is 1, 2 or 3; R.sup.4, X and t are as defined above; N.sup.+ in formula (2) is connected to R.sup.3 in formula (1); and (CH.sub.2), is connected to the quaternary nitrogen atom in formula (1); c) mixing the at least one white pigment and impurities containing material of step a) and the at least one collector agent of step b) in an aqueous environment to form an aqueous suspension; d) passing gas through the suspension formed in step c); and e) recovering the white pigment containing product by removing the white pigment bearing phase from the aqueous suspension obtained after step d).

2. The process according to claim 1, wherein the process comprises conducting an indirect flotation step that forms a froth containing the impurities and a white pigment bearing phase with the white pigment containing product.

3. The process according to claim 1, wherein the white pigment is a white mineral pigment.

4. The process according to claim 3, wherein the white mineral pigment is an alkaline earth metal carbonate.

5. The process according to claim 4, wherein the white mineral pigment is a calcium carbonate.

6. The process according to claim 5, wherein the calcium carbonate is ground calcium carbonate.

7. The process according to claim 3, wherein the white pigment is selected from the group consisting of natural calcium carbonate, ground calcium carbonate, calcium carbonate-comprising mineral material, dolomite, barite, aluminium oxide, titanium dioxide and mixtures of the foregoing.

8. The process according to claim 1, wherein the white pigment containing material comprises impurities selected from the group consisting of iron sulphides, iron oxides, graphite, silicates and mixtures thereof.

9. The process according to claim 8, wherein the silicate is selected from the group consisting of quartz, a mica, an amphibolite, a feldspar, a clay mineral and mixtures thereof.

10. The process according to claim 9, wherein the silicate is quartz.

11. The process according to claim 8, wherein the silicate is a white colored silicate selected from the group consisting of wollastonite, kaolin, kaolinitic clay, calcined kaolinitic clay, montmorillonite, talc, diatomaceous earth, sepiolite and mixtures thereof.

12. The process according to claim 1, wherein the amount of white pigment in the at least one white pigment and impurities containing material of step a) is from 0.1 wt.-% to 99.9 wt.-%, based on the dry weight.

13. The process according to claim 12, wherein the amount of white pigment in the at least one white pigment and impurities containing material of step a) is from 30 wt-% to 99.7 wt.-% based on the dry weight.

14. The process according to claim 12, wherein the amount of white pigment in the at least one white pigment and impurities containing material of step a) is from 60 wt.-% to 99.3 wt.-% based on the dry weight.

15. The process according to claim 12 wherein the amount of white pigment in the at least one white pigment and impurities containing material of step a) is from 80 wt.-% to 99 wt.-% based on the dry weight.

16. The process according to claim 1, wherein the ratio of white pigment: impurities in the at least one white pigment and impurities containing material of step a) is from 0.1:99.9 to 99.9:0.1, based on the dry weight.

17. The process according to claim 16, wherein the ratio is from 30:70 to 99.7:0.3.

18. The process according to claim 16, wherein the ratio is from 60:40 to 99.3:0.7.

19. The process according to claim 16, wherein the ratio is from 80:20 to 99:1.

20. The process according to claim 1, wherein the at least one white pigment and impurities containing material of step a) has a weight median grain diameter in the range of from 1 m to 1,000 m.

21. The process according to 20, wherein the diameter is from 3 m to 700 m.

22. The process according to claim 20, wherein the diameter is from 5 m to 500 m.

23. The process according to claim 20, wherein the diameter is from 10 m to 80 m.

24. The process according to claim 20, wherein the diameter is from 100 m to 400 m.

25. The process according to claim 1, wherein the wherein in the compound of formula (1): R.sup.1CO is selected from the group consisting of a saturated or unsaturated, linear or branched acyl group having 12 to 24 carbon atoms; R.sup.2 represents an alkylene radical having from 2 to 6 carbon atoms; R.sup.3 represents a hydrocarbyl group containing from 12 to 24 carbon atoms or a group of formula R.sup.5O-(AO).sub.w-T-; wherein R.sup.5 represents a hydrocarbyl group having from 12 to 24 carbon atoms; w is a number ranging from 0 to 10; AO represents an alkyleneoxy group having from 2 to 4 carbon atoms; and T represents an alkylene group having from 1 to 4 carbon atoms; R.sup.4 represents an alkyl group having from 1 to 4 carbon atoms; X represents halogen, sulphate or carbonate; AO represents an alkyleneoxy group having from 2 to 4 carbon atoms; x is a number within the range from 1 to 10; and p is a number within the range from 1 to 10.

26. The process according to claim 25, wherein the acyl group has 14 to 24 carbon atoms.

27. The process according to claim 25, wherein the acyl group has 16 to 24 carbon atoms.

28. The process according to claim 25, wherein R.sup.2 is an alkylene radical having 4 carbon atoms.

29. The process according to claim 25, wherein w represent a number from 0 to 3.

30. The process according to claim 25, wherein T is an alkylene group having from 2 to 3 carbon atoms.

31. The process according to claim 25, wherein AO is an alkyleneoxy group having 2 carbon atoms.

32. The process according to claim 25, wherein x is a number within the range from 1 to 6.

33. The process according to claim 25, wherein p is a number within the range from 1 to 5.

34. The process according to claim 1, wherein the compound as provided in step b) is selected from the group consisting of compounds of formula (1a): ##STR00018## wherein, AO, p, t, x, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and X are as defined in claim 1.

35. The process according to claim 34, wherein in the compound of formula (1a): R.sup.1CO is selected from the group consisting of a saturated or unsaturated, linear or branched acyl group having from 12 to 24 carbon atoms; R.sup.2 represents an alkylene radical having from 1 to 20 carbon atoms; R.sup.3 represents a hydrocarbyl group having from 8 to 24 carbon atoms; R.sup.4 represents a hydrocarbyl group having from 1 to 4 carbon atoms; AO is an alkyleneoxy group having 2 to 4 carbon atoms; X is an anion derived from an alkylating agent R.sup.4X, wherein X represents halogen, sulphate or carbonate; x is a number within the range from 1 to 15; p is a number within the range from 1 to 15; and t is 0 or 1.

36. The process according to claim 35, wherein the acyl group has from 14 to 24 carbon atoms.

37. The process according to claim 35, wherein the acyl group has from 16 to 24 carbon atoms.

38. The process according to claim 35, wherein R.sup.2 is an alkylene radical having from 1 to 10 carbon atoms.

39. The process according to claim 35, wherein R.sup.2 is an alkylene radical having from 2 to 6 carbon atoms.

40. The process according to claim 35, wherein R.sup.2 is an alkylene radical having 4 carbon atoms.

41. The process according to claim 35, wherein R.sup.3 is a hydrocarbyl group having from 12 to 24 carbon atoms.

42. The process according to claim 35, wherein R.sup.4 is an alkyl group having 1 or 2 carbon atoms.

43. The process according to claim 35, wherein R.sup.4 is a methyl group.

44. The process according to claim 35, wherein AO is an ethoxy group.

45. The process according to claim 35, wherein X is derived from chloride or sulphate.

46. The process according to claim 35, wherein x is a number within the range from 2 to 10.

47. The process according to claim 35, wherein x is a number within the range from 1 to 6.

48. The process according to claim 35, wherein t is 1.

49. The process according to claim 34, wherein in the compound of formula (1a): R.sup.1 is derived from a fatty acid selected from the group consisting of 2-ethylhexanoic acid, n-octanoic acid, n-decanoic acid, n-dodecanoic acid, n-tetradecanoic acid, n-hexadecanoic acid, palmitoleic acid, n-octadecanoic acid, oleic acid, linoleic acid, eicosanoic acid, docosanoic acid, tetracosanoic acid, coco fatty acid, rape seed fatty acid, soya fatty acid, tallow fatty acid, palm oil fatty acid, tall oil fatty acid, gadoleic acid, erucic acid, hydrogenated forms of these acids and mixtures thereof; R.sup.2 is derived from a dicarboxylic acid, a dicarboxylic acid chloride, a diester of a dicarboxylic acid, an anhydride of a dicarboxylic acid; R.sup.3 is derived from a fatty amine selected from the group consisting of 2-ethylhexylamine, 2-propylheptylamine, n-octylamine, n-decylamine, n-dodecylamine, (coco alkyl)-amine, (palm oil alkyl) amine, n-tetradecylamine, n-hexadecylamine, n-octadecylamine, oleylamine, (tallow alkyl)-amine, (hydrogenated tallow alkyl)-amine, Grape seed alkyl)-amine, (soya alkyl)-amine, erucyl amine, N-(n-decyl)-N-methyl-trimethylene-diamine, N-(n-dodecyl)-N-methyl-trimethylene-diamine, N-(coco alkyl)-N-methyHrimethylene-diamine, N-(rape seed alkyl)-N-methyl-trimethylene-diamine, N-(soya alkyl)-N-methyl-trimethylene-diamine, N-(tallow alkyl)-N-methyl-trimethylene-diamine, N-(hydrogenated tallow alkyl}-N-methyl-trimethylene-diamine, N-(erucyl)-N-methyl-trimethylene-diamine, isotridecyloxypropylamine and mixtures thereof; and R.sup.4 is derived from an alkylating agent selected from the group consisting of dimethyl sulphate, diethyl sulphate, dimethyl carbonate, benzyl chloride, methyl bromide, methyl chloride, methyl iodide, preferably dimethyl sulphate or methyl chloride and mixtures thereof.

50. The process according to claim 49, wherein R.sup.1 is derived from tallow fatty acid.

51. The process according to claim 49, wherein R.sup.2 is derived from a compound selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, glutaconic acid, adipic acid, muconic acid, pimelic acid, phthalic acid, terephthalic acid, tetrahydrophthalic acid, malic acid, maleic acid, fumaric acid, suberic acid, mesaconic acid, sebacic acid, azelaic acid, tartaric acid, itaconic acid, glutinic acid, citraconic acid, brassylic acid, dodecanedioic acid, traumatic acid, thapsic acid, the corresponding acid chlorides, methyl or ethyl esters or anhydrides of these compounds and mixtures thereof.

52. The process according to claim 49, wherein R.sup.2 is derived from a compound selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, phthalic acid, tetrahydrophthalic acid, malic acid, tartaric acid, the corresponding acid chlorides, methyl or ethyl esters or anhydrides of these compounds and mixtures thereof.

53. The process according to claim 49, wherein R.sup.2 is derived from adipic acid.

54. The process according to claim 49, wherein R.sup.3 is derived from (coco alky)-amine or (tallow alkyl)-amine.

55. The process according to claim 34, wherein, the at least one collector agent of step b) comprises one or more compounds of formula (1) and/or formula (1a).

56. The process according to claim 34, wherein one or more additives are added to the aqueous suspension prior to, during or after step c), and wherein the one or more additives are selected from the group consisting of pH-adjusting agents, solvents, depressants, polyelectrolytes, frothers and collector agents other than the collector agents according to formula (1) or (1a).

57. The process according to claim 1, wherein the aqueous suspension obtained in step c) has a pH from 7 to 10.

58. The process according to claim 57, wherein the pH is from 7.5 to 9.5.

59. The process according to claim 57, wherein the pH is from 8.5 to 9.0.

60. The process according to claim 1, wherein the at least one collector agent is added in step c) in an amount of from 1 ppm to 5,000 ppm based on the total dry weight of the white pigment and impurities containing material of step a).

61. The process according to claim 60, wherein the amount is from 20 ppm to 2,000 ppm.

62. The process according to claim 60, wherein the amount is from 30 ppm to 1,000 ppm.

63. The process according to claim 60, wherein the amount is from 50 ppm to 800 ppm.

64. The process according to claim 1, wherein the aqueous suspension obtained in step c) has a solids content of from 5 wt-% to 80 wt.-% based on the total weight of the solids in the suspension.

65. The process according to claim 64, wherein the solids content is from 10 wt.-% to 70 wt.-%.

66. The process according to claim 64, wherein the solids content is from 20 wt.-% to 60 wt.-%.

67. The process according to claim 64, wherein the solids content is from 25 wt.-% to 55 wt.-%.

68. The process according to claim 1, wherein the aqueous suspension obtained in step c) is ground during and/or after step c).

69. The process according to claim 1, wherein the gas in step d) is air.

70. The process according to claim 1, wherein the suspension in step d) has a temperature of from 5 C. to 40 C.

71. The process according to claim 70, wherein the temperature is from 10 C. to 40 C.

72. The process according to claim 70, wherein the temperature is from 10 C. to 30 C.

73. The process according to claim 72, wherein the temperature is from 15 C. to 25 C.

74. The process according to claim 1, wherein the white pigment bearing phase obtained from step e) is dispersed and/or ground before and/or after step e).

75. The process according to claim 74, wherein the white pigment bearing phase is dispersed and/or ground in the presence of at least one dispersing agent and/or at least one grinding aid agent.

76. The process according to claim 1, wherein R.sup.2 is an alkylene radical having from 1 to 20 carbon atoms.

77. The process according to claim 76, wherein the alkylene radical has 1 to 10 carbon atoms.

78. The process according to claim 76, wherein the alkylene radical is a substituted alkylene radical.

79. The process according to claim 78, wherein the substituted alkylene radical is substituted by 1 or 2 OH groups, 1 or 2 methyl and/or methylene groups, a cycloalkylene group, a cycloalkenylene group and/or an arylene group.

80. The process according to claim 1, wherein R.sup.2 is an alkenylene radical having from 1 to 20 carbon atoms.

81. The process according to claim 80, wherein the alkenylene radical has from 1 to 10 carbon atoms.

82. The process according to claim 80, wherein the alkenylene is a substituted alkenylene radical.

83. The process according to claim 82, wherein the substituted alkenylene radical is substituted by 1 or 2 OH groups, 1 or 2 methyl and/or methylene groups, a cycloalkylene group, a cycloalkenylene group and/or an arylene group.

84. A method of preparing at least one of paper, plastic, paint, coatings, concrete, cement, cosmetics, water treatment, food, pharma, ink and/or agriculture applications, the method comprising the step of incorporating the white pigment containing product of claim 1 in at least one of the paper, plastic, paint, coatings, concrete, cement, cosmetics, water treatment, food, pharma, ink and/or agricultural applications, wherein the application optionally comprises a wet end process of a paper machine, cigarette paper, paper board, and/or coating applications, or in a support for rotogravure and/or offset and/or ink jet printing and/or continuous ink jet printing and/or flexography and/or electrophotography and/or decoration surfaces.

Description

EXAMPLES

(1) 1 Measurement Methods

(2) pH Measurement

(3) The pH was measured at 25 C. using a Mettler Toledo Seven Easy pH meter and a Mettler Toledo InLab Expert Pro pH electrode. A three point calibration (according to the segment method) of the instrument was first made using commercially available buffer solutions having pH values of 4, 7 and 10 at 20 C. (from Aldrich). The reported pH values were the endpoint values detected by the instrument (the endpoint was when the measured signal differs by less than 0.1 mV from the average over the last 6 seconds).

(4) Particle Size Distribution (Mass % Particles with a Diameter <X) and Weight Median Grain Diameter (do) of Particulate Material

(5) The Particle Size Distribution (PSD) and the correlating median grain diameter d.sub.50 were measured by Laser Diffraction Analyzers; either by Malvern Mastersizer 2000 in case of a d.sub.50 above 5 m or by a Micromeritics Sedigraph 5120 in case of finer materials (<5 m). The measurement was carried out in an aqueous solution of 0.1% by weight of Na.sub.4P.sub.2O.sub.7 and the samples were dispersed using a high speed stirrer and ultrasonic before. While the Sedigraph works via the sedimentation method, i.e. an analysis of sedimentation behaviour in a gravimetric field, the Mastersizer runs in a circulation mode.

(6) Weight Solids (Wt.-%) of a Material in Suspension

(7) The weight solids were determined by dividing the weight of the solid material by the total weight of the aqueous suspension. The weight of the solid material is determined by weighing the solid material obtained by evaporating the aqueous phase of suspension and drying the obtained material to a constant weight.

(8) Specific Surface (BET) Measurement

(9) The specific surface area (in m.sup.2/g) of the white pigment or of the impurities was determined using nitrogen and the BET method, which is well known to the skilled man (ISO 9277:2010). The total surface area (in m.sup.2) of the white pigment or of the impurities was then obtained by multiplication of the specific surface area and the mass (in g) of the white pigment or of the impurities. The method and the instrument are known to the skilled person and are commonly used to determine specific surface of white pigments or of the impurities.

(10) Brightness Measurement and Yellow Index (=YI)

(11) The samples from the flotation process were dried by use of microwave. The obtained dry powders were prepared in a powder press to get a flat surface and Tappi brightness (R457 ISO brightness) is measured according to ISO 2469 using an ELREPHO 3000 from the company Datacolor. The results for the Tappi brightness are given as percentage in comparison to a calibration standard.

(12) The yellow index has been calculated by the following formula:
YI=100*(R.sub.xR.sub.z)/R.sub.y)
Determination of the HCl Insoluble Content

(13) 10 g crude material (dry product or slurry under consideration of the solid content) were weighted into a 400 ml beaker, suspended in 50 ml demineralized (demin.) water and mixed with 40 ml HCl (8N=25%). After the formation of carbon dioxide has been finished the mixture was boiled for 5 minutes, cooled to room temperature and subsequently strained over a previously weighed membrane filter. The beaker wall was rinsed 3 times with 20 ml demin. water and afterwards the filter was dried at 105 C. in the microwave until weight constancy is reached. After the filter cooled down in the desiccator it was weighed back and the HCl insoluble (insoL) content was calculated according to following equation:

(14) $\mathrm{HCl}-\mathrm{insol}.\mathrm{content}\left[\%\mathrm{by}\mathrm{weight}\right]=\frac{\mathrm{filter}\mathrm{gross}\left[g\right]-\mathrm{filter}\mathrm{tare}\left[g\right]}{\mathrm{weighed}\mathrm{sample}\left[g\right]\left(\mathrm{dry}\mathrm{mass}\mathrm{of}\mathrm{slurry}\right)}100\%$
Determination of Load Capacity (Surface Charge)

(15) The surface charge of the collector agent bearing particles in the slurry was measured by a Mtek Particle Charge Detector (PCD04 from BTG) using titration with sodium polyethylenesulphonate (Na-PES) in [Val/Kg].

(16) Determination of the Acid Value

(17) The acid value has been measured by potentiometric titration using potassium hydroxide solution as the reagent and isopropyl alcohol as a solvent.

(18) In a 250 mL beaker, about 10 g of sample to analyze is precisely weighed (Sw, precision to the mg) and 70 mL of isopropyl alcohol are added. The mixture has been agitated and heated gently if necessary to get a homogeneous sample. The titrator combined glass reference electrode has been introduced into the solution, which has been then agitated with a magnetic stirrer. The acid-base titration of the sample has been performed using 0.1 N aqueous potassium hydroxide (KOH) solution and the pH evolution has been recorded on the titrator. The equivalent point has been graphically determined using methods known to the skilled in the art, and the volume (V.sub.KOH, in mL) of potassium hydroxide solution used to reach this point has been determined. The acid value (AV) has then been obtained according to the following calculation:

(19) $\mathrm{AV}=\frac{\left[\mathrm{Normality}\mathrm{of}\mathrm{KOH}\mathrm{solution}\left(\mathrm{mol}/L\right)\right]56.1V_{\mathrm{KOH}}}{\mathrm{Sw}}$
2 Collector Agents

(20) Synthesis of collector agent 1 (CA1)

(21) 567 g of hydrogenated tallow fatty acid and 0.3 g of hypophosphorous acid (50%) were introduced in a 4 litres round bottom flask. The mixture was heated to 80 C. with nitrogen bubbling, afterwards the bubbling was stopped and 219 g of adipic acid were added under agitation. After 15 minutes 1 872 g of ethoxylated coco alkyl amine (Noramox C5, supplied by CECA, France, contains 5 moles of ethoxy groups) where added while increasing the temperature to 120 C. Afterwards the temperature of the mixture was raised to 160 C. over a period of 1 hour and the pressure in the vessel was lowered progressively until a pressure of 6.67 kPa (50 mm Hg) was reached. After one hour at 160 C. and 6.67 kPa the mixture was heated to 200 C. and the mixture was kept at that temperature for 4 hours. Afterwards, the temperature was raised to 190 C. and maintained until almost all acid is consumed (acid value<5 meq/g). The mixture was cooled down to 60 C. and the resulting esteramine (3) was recovered without any further treatment.

(22) 2 000 g of esteramine (3) were charged in a 6 litres glass reactor and 300 g iso-propanol were added. Methyl chloride was added until the pressure in the glass reactor reached 2.9 bars, then the temperature was raised to 85 C. and the mixture was kept between 80 to 85 C. until complete reaction has occurred (complete reaction is achieved when the total amount of basic nitrogen is less or equal to 0.2 mmol.Math.g1 as measured by titration with 0.2 N hydrochloric acid in iso-propanol). Afterwards the mixture was allowed to cool down to 65 C. and the pressure was reduced to atmospheric pressure. After 2 hours of nitrogen bubbling through the mixture the obtained collector agent 1 (CA1) was recovered and diluted with iso-propanol to reach an iso-propanol-content of 30 wt.-% as determined by proper gas chromatography analysis. The collector agent (CA) is also known as polymer of adipic acid and hydrogenated tallow fatty acid with ethoxylated coco alkyl amine (also known as (coco alkyl)-amine) (5OE) which is totally quaternised with methyl chloride.

(23) Collector Agent 2 (CA2) (Comparative)

(24) Reagent Lupromin FP 18 AS, polymeric esterquat, commercially available from BASF

(25) Collector Agents 3 to 9 (CA3 to CA9)

(26) The following other collector agents (CA3 to CA9) have been prepared following the same reaction conditions as in example 1 and are obtained by reacting the following compounds:

(27) TABLE-US-00001 TABLE 1 Collector agents CA3 to CA9. Alkylating Fatty Alkoxylated Dicarboxylic acid agent R.sup.4X for Collector acid fatty amine or a derivative Molar ratio Molar ratio quaternisation agents (I) (III) (II) (I)/(III) (II)/(III) reaction CA3 tallow ethoxylated adipic acid 0.5 0.75 methyl chloride fatty tallow alkyl acid amine (5OE) CA4 tallow ethoxylated adipic acid 0.5 0.75 methyl chloride fatty coco alkyl acid amine (2OE) CA5 coco ethoxylated sebacic acid 0.5 0.75 methyl chloride fatty tallow alkyl acid amine (2OE) CA6 tallow ethoxylated maleic 0.4 0.6 methyl chloride fatty tallow alkyl anhydride acid amine (5OE) CA7 palm ethoxylated adipic acid 0.4 0.6 methyl chloride oil fatty palm oil alkyl acid amine (5OE) CA8 tallow ethoxylated maleic 0.4 0.6 methyl chloride fatty coco alkyl anhydride acid amine (2OE) CA9 tallow ethoxylated adipic acid 0.4 0.6 methyl chloride fatty tallow alkyl add amine (11OE)

(28) In Table 1 the fatty acids of formula (1) and the alcoxylated fatty amine of formula (III) are described by the origin of the fatty alkyl chain. The number of ethylene oxide (OE) equivalents that have been reacted with the fatty alkyl amine are given in brackets. All collector agents CA3 to CA9 are totally quaternised.

(29) The collector agent CA3 to CA9 also shown good properties in the process for manufacturing white pigment containing products according to the present invention.

(30) 3 Flotation Trials

(31) All froth flotation trials were performed at room temperature (20+2 C.) in an Outotec laboratory flotation cell, equipped with a conical gassing agitator under agitation of 1 600 rpm under use of a 4 dm.sup.3 capacity glass cell. The solids content of the aqueous white pigment and impurities containing material suspension added to the flotation machine was of 33% by dry weight, said white pigment and impurities containing material being sourced from sedimentary marble rock deposits with different origins, running already a flotation process. The used water was original tab water from each local flotation process.

(32) 80% a typical practiced dosage of the flotation agent were given in the beginning of the trial and mixed within a 2 min conditioning time. A second dosage was added depending on the achieved froth product and visual seen impurities in the cell.

(33) A flotation gas, consisting of air, was then introduced via orifices situated along the axis of the agitator at a rate of approximately 2 dm.sup.3/min.

(34) The foam created at the surface of the suspension was separated from the suspension by overflow and skimming until no more foam could be collected, and both the remaining suspension and the collected foam were dewatered and dried in order to form two concentrates for mass balance and quality analyses like carbon fraction determination.

(35) Comparative Examples are marked with a C after the Example number.

Examples 1 to 3

(36) For Examples 1 to 3 a white pigment and impurities containing material from Gummern marble deposit in Austria is selected. The material contains 321 wt.-% of impurities determined by carbon fraction determination. The material is crushed and pre ground to a median grinding size d.sub.50 of 20 m. The material is treated according to the above mentioned process. The test data are summarized in the following Table 2.

(37) TABLE-US-00002 TABLE 2 Flotation trials. Flotation data White pigment comprising Amount of product Collector Flotation Tappi- Test Collector agent time Impurities bright- Yellow- No. agent [ppm] [minutes] [wt.-%].sup.a) ness index 1 CA1 400 15 0.06 93.16 2.62 2 CA1 500 20 0.04 93.93 2.26 3 CA1 600 25 0.02 94.37 2.05 4C CA2 400 20 0.95 90.70 1.94 5C CA2 500 20 0.08 93.58 2.22 6C CA2 600 25 0.06 93.90 2.09 .sup.a)Impurities expressed as compounds insoluble in 8N HCl.

(38) As can be gathered from Examples 1 to 3 the inventive process for manufacturing white pigment comprising products shows good results (low amount of impurities in the white pigment containing product, high values for Tappi-brightness and low values for yellow-indices) even at low amounts of collector agent (Example 1: 400 ppm) within the aqueous suspension. A process according to Comparative Examples 4C to 6C uses collector agents according to the prior art and yields a product comprising a higher amount of impurities and having particularly at lower collector agent amounts (cf. Example 1 with Comparative Example 4C) a lower brightness.

(39) 4 Stability Tests

(40) To investigate the stability of the reagent, it was stirred in parallel at 20 C. and at 40 C. for 24 h and the reduction of the positive Mytek charge was controlled for defined time periods by using Na-PES as anionic titration agent. The resulting products were used afterwards for lab flotation tests in comparison to the original ones. The flotation tests were done at natural pH of 8.5 to 9.

(41) TABLE-US-00003 TABLE 3 Stability tests. Temperature Time Load capacity Collector agent [ C.] [h:min] [Val/kg] CA1 (inventive) 20 0 8 624 CA1 (inventive) 20 1:41 8 673 CA1 (inventive) 20 5:00 8 201 CA1 (inventive) 20 24:47 7 155 CA1 (inventive) 40 0 8 624 CA1 (inventive) 40 1:12 8 692 CA1 (inventive) 40 5:29 8 182 CA1 (inventive) 40 22:52 7 252 CA2 (comparative) 20 0 12 051 CA2 (comparative) 20 1:38 11 075 CA2 (comparative) 20 4:58 90 53 CA2 (comparative) 20 23:30 61 63 CA2 (comparative) 40 0 12 051 CA2 (comparative) 40 1:12 8 805 CA2 (comparative) 40 5:29 6 320 CA2 (comparative) 40 22:52 5 101

(42) The load capacity of the collector agent according to the invention reduces by 17% at 20 C. and by 16% at 40 C. after approximately 24 h, whereas the collector agent according to the prior shows a reduction of the load capacity by 49% at 20 C. and 58% at 40 C. The results confirm that the collector agents according to the invention show a higher stability in comparison to prior art collector agents.

(43) Flotation trials according to the conditions as given in section 3 have been carried out with the original collector agents (test no. 10 and 12C) and with collector agents which have been stored for 24 h at 40 C. as a 1 wt.-% aqueous solution (test no. 11 and 13C).

(44) TABLE-US-00004 TABLE 4 Flotation trials. White pigment Flotation data comprising Amount of Flotation product Test Collector Collector time Impurities No. agent agent [ppm] [minutes] [wt.-%].sup.a) 7 CA1 600 25 0.02 8 CA1 600 25 0.05 9C CA2 600 30 0.06 10C CA2 600 30 1.49 .sup.a)Impurities expressed as compounds insoluble in 8N HCl.

(45) The results shown in Table 4 above confirm that the performance of the collector agents according to the invention after and before storage is higher than the performance of the prior art collector agents. Even after 24 h storage the performance of the collector agents according to the invention is higher than the performance of the original prior art collector agents (comparison of test no. 8 with test no. 9C).