CN1010769B - Process for preparing pigmentary titanium dioxide - Google Patents

Abstract

The present invention relates to a preparation method of TiO2 pigment, which comprises the following steps: a material containing titanium, such as slag((sorelslag), is ground and mixed with an alkali metal compound, such as NaOH, and the mixture is roasted so as to be used the material for preparing TiO2 pigment; after being ground by sanding, the roasted material is washed and filtered; then solid residue is digested with HCl; after being filtered and washed to eliminate the acid, the solid residue is calcined for providing TiO2 pigment. The method of the present invention can produce granular and acicular TiO2 pigment by adopting proper technology conditions.

Description

Process for preparing pigmentary titanium dioxide

The present invention relates to a kind of method for preparing TiO 2 pigment in the titanic oxide material that is mixed with.More particularly, only providing a kind of easy and relatively cheap method with preparation TiO ₂Pigment, in view of the above, the raw material or the useful composition of the titanium in the ore that contain titanium dioxide be not dissolved or change into gasifiable fluid cpds, but separate from gangue and wear into the required particle of pigment with mechanical means by solid-liquid reaction.

Present method provides acquisition needle-like or granular TiO ₂The means of pigment.

Titanium dioxide (TiO ₂) be of great use Opacifying pigment in the paint of knowing, the filler of the coating composition of plastic material and paper and other material.Known have various production TiO ₂Method, for example, be commonly referred to the ordinary method of sulphate process and chloride process.

Sulphate process is with the titanium in the concentrated sulfuric acid dissolution low-grade titanium ore, as ilmenite or Sorel slag (Soreisiag), and removes carefully that institute's sulphur that generates arrives ferrous in the technological process.Then by precipitation, wash, calcining step makes and generates pigment TiO ₂

Chloride process is to make the higher-grade titanium ore, (contains about 95%TiO as Australian golden red stone ₂) or the higher-grade richness select the useful composition of titanium in the ilmenite to evaporate with the form of tetrahalide.And then through purifying and oxidation step.

Sulphate process and chloride process are very complicated, and this also is to cause with these two kinds of methods to produce TiO ₂The basic place that the pigment cost is higher.

Therefore, the objective of the invention is to prepare the method for TiO 2 pigment, the steps include:

(a) raw material that will contain titanium dioxide becomes the particle of diameter 0.5 to 3mm size in grinding machine for grinding;

(b) raw material that will contain titanium dioxide mixes with alkali metal compound, and alkali metal compound is selected from alkali-metal oxyhydroxide, carbonate and oxide compound; The raw material that wherein contains titanium dioxide is 100 with the ratio of alkali metal hydroxide: 30-100: 60(by weight).

(c) after step (a), the mixture that will contain the raw material of titanium dioxide and water grinds to form the particle less than 15 μ m, or after step (b), and the mixture that will contain the raw material of titanium dioxide and alkali metal compound and water grinds to form the particle less than 15 μ m.

(d) at 700 ℃ of-950 ℃ of these mixtures of roasting;

(e) this calcining matter of digestion 10-20 minute in hydrochloric acid; With

(f) solid that obtains in the digestion step is calcined down to generate TiO 2 pigment at 800 ℃-1000 ℃.

Fig. 1 is a schema of implementing method of the present invention.

The initiation material that is used for the inventive method is a titaniferous materials such as Sorel slag (Sorelslag). The Sorel slag of various grades all can be used for the present invention. As, a Typical Cable riel slag forms and is about 70%TiO by the oxide weight percentage₂, the assorted value of about 11%FeO and all the other impurity as, CaO, MgO, SiO₂，Al ₂O ^＊ ₃，MnO，V ₂O ₅，Cr ₂O ₃And other micro-oxide impurity. Another useful Sorel slag forms and is about 78%TiO in the method₂, 8%FeO impurity and as above-mentioned residual impurity.

Should be appreciated that the present invention is not limited to Sorel slag (Sorelslag). Therefore, other titanium-containing materials and ore are as initiation material also within the scope of the present invention. For example, chloride slag (Chloride Slag) also can be used for the present invention. Typical chloride slag contains 85%TiO approximately₂, about 10%FeO impurity and as above-mentioned residual impurity.

Another raw material that is suitable for the inventive method can be the intermediate product in the ilmenite refining process, as U.S. Patent No. 3,825, reaches described in 419. The typical feedstock that generates in above-mentioned refining process forms and is about 95%TiO₂, about 1%FeO impurity and above-mentioned remaining impurity.

The example that can be used for other titanium-containing materials of the inventive method is any titanium-containing materials, and this material is so processed, and when being heated to 700 ℃-950 ℃, its titanium oxide partly can react with alkali metal compound. Certain alkali metal compound used herein comprises, for example, and alkali metal hydroxide, alkali carbonate, or alkali metal oxide or its mixture.

Be used for to pulverize among the present invention, mix, roasting is filtered, calcining take and the equipment of all operations as being suitable for continuously or the conventional equipment of batch operation. For the titaniferous initial feed is ground to form micron particles, the most handy such as U.S. Patent No. 2,581, the sand mill (Sandmills) that reaches described in 414. Here sand milling technology refers to U.S. Patent No. 2,581, reaches the technical process that equipment grinds to form raw material micron particles described in 414. Yet the abrasive media that is used for this equipment is not limited to sand, can also be glass, steel, and pottery or other have the suitable abrasive media of sphere or pearl, and its diameter is in 0.5-3 millimeter scope in general.

Digestion step is finished in a container, and this container should have acidproof inner surface or a liner, under normal operating condition, and the corrosion of used acid in the anti-technology of energy. For example, be suitable for as inner lining material glass being arranged, the polymer that the FRP(glass fibre is strengthened), polyester, acrylic acid, epoxy resin and other suitable plastics, haas troy hastelloy (Ni/MO alloy), rubber, refractory metal (Ta, Zr, Cb) or acidproof brick.

The most preferred embodiment according to the present invention, the particle diameter of titaniferous materials should be enough little in order to react with alkali metal compound all or almost all. Referring to Fig. 1, the preliminary grinding of titaniferous materials elder generation is as being ground into the granular size that is suitable for sand milling with sledge mill. Below take the Sorel slag as titaniferous materials illustrates method of the present invention, as aforementioned, the raw materials used Sorel slag that is not limited to.

Behind the sledge mill, slag sand is worn into mean particle size less than 15 microns, granularity is then more desirable less than 10 microns.More can be what get is that raw material maximum particle size sand milling is become 10 microns or littler.Particle then can be mingled with some impurity greater than 15 microns, and these impurity are difficult for removing from raw material in post-processing step of the present invention.

After slag is ground into suitable particle, with alkali metal compound, as, alkali metal hydroxide, carbonate, oxide compound or its mixture, uniform mixing.Basic metal comprises, sodium, potassium, rubidium, caesium, or their mixture.The most desirable compound is an alkali metal hydroxide, and sodium hydroxide is then more desirable, because it is easy to react with the levigated slag material.Below be that example is illustrated method of the present invention as preferred alkali metal compound just with sodium hydroxide, but should be appreciated that and the invention is not restricted to this.

Sodium hydroxide can just mix with the Sorel raw material before roasting, was preferably in the sand grinding process, perhaps before the sand milling step.Mixture can contain 30 parts of weights (pbw) or be higher than the sodium hydroxide of 30 parts of weights, the Sorel slag of 100 parts of weights.Preferably the sodium hydroxide of 30～60pbw is to the slag of 100pbw.More preferably the weight ratio of slag and sodium hydroxide is from 100: 35 to 100: 45.The ratio of slag and sodium hydroxide is lower than 100: 30 or is higher than 100: 60 also is feasible, yet may can not get gratifying TiO ₂Product.TiO in raw materials used ₂Be higher than at 70% o'clock, amount of sodium hydroxide should corresponding increase in the mixture.

Behind the sand milling, the mixture of slag and sodium hydroxide is 700 ℃-950 ℃ down heating or roastings 1～3 hour.Maturing temperature is higher than 950 ℃ can form lump or molten slag, and then reaction is not exclusively between Sorel slag and the sodium hydroxide if be lower than 700 ℃.Therefore, preferably at 800 ℃ of-870 ℃ of following roasting 1.5-2 hours.Preferably the mixture after the roasting is ground to form the particle of 0.5-2 micron.As mentioned above, thin particle helps to remove impurity in follow-up processing.

In the calcination steps, should be sure of the TiO in the mixture ₂Generate sodium titanate with the sodium hydroxide reaction.Some impurity in the raw material also can generate an alkali metal salt can extractive form existing with the oxyhydroxide reaction.For example, when using sodium hydroxide, the impurity that exists with alkali metal salt has sodium vanadate, Sodium chromate, and sodium aluminate, and water glass, these salt are soluble in water.Therefore, preferably these impurity are soluble in water at least in part after the roasting by washing, to reduce, preferably remove these deleterious impurity basically fully.Other impurity such as ferric oxide in the raw material, magnesium oxide and calcium oxide are soluble in the example hydrochloric acid at mineral acid, and can remove in following digestion step.

After water-soluble impurity eccysis or is dissolved from calcining matter, remaining water-insoluble basic metal hydrochlorate and the digestion in hydrochloric acid of non-dissolubility oxide compound.The most handy about 6NHCl is because Ruo acid is effective unlike 6NHCl again.More effective with denseer acid meeting in a pressurizing vessel, but when container opened at atmosphere and boils, concentrated acid then was tending towards 6HNCl.Therefore, use be low to moderate the 5N height to the concentrated acid of 12N all fully within the scope of the invention.Yet, when used acid concentration surpasses 6N (the HCl azeotropic point is 108 ℃ during this concentration), need a pressurizing vessel.Therefore atmospheric operation is more practical.

Under a standard pressure, digestion step is finished under 80 ℃ or higher temperature, preferablely refluxes down at 90 ℃-110 ℃, and is more desirable under 108 ℃, and backflow 10-120 minute, preferably 10-40 minute.Yet higher temperature also can use, but needs pressure exerting device.More than above-mentioned digestion step can be carried out once, yet carry out at least twice for well.

Granular or needle-like TiO ₂Acquisition depend on that calcining matter (sodium titanate) is being lower than under about 90 ℃ hold-time length in 6NHCl.When the acid suspended substance of 6N in digestion step when slowly (less than 5 °/minute) are heated to 108 ℃ of its boiling temperatures, product is mainly granular TiO ₂When the digestion mixture heat up very fast or in heating steps acid concentration be lower than 4N and when temperature is tending towards 90 ℃ of acidity and is increased to 6N product be mainly needle-like shape.

In the preferred embodiment of the invention, baked material at room temperature (20～30 ℃) mixes with HCl.The mixture of baked material and acid slowly is heated to the boiling temperature of acid, and heating rate is 5 ℃/minute or lower, and best 2 ℃/assign to 3 ℃/minute, 2 ℃/minute or lower then more desirable.Be sure of in digestion step, to have generated granular sodium titanate.No matter obtaining the partical or the situation of spicule, with the outstanding absurd creature ebuillition of heated backflow certain hour of washed calcining matter in about 6N hydrochloric acid to finish digestion step.Boiling point changes with pressure, and its scope is at 90 ℃-111 ℃, and is the most desirable with 108 ℃.Digestion was finished in 10～15 minutes substantially.The digestion time can be grown to 120 minutes, but best with 10-40 minute.Also can use high heating rate and long-time heating, but need pressure exerting device.

In the digestion step, be sure of that alkali metal titanate is hydrolyzed into amorphous hydrate TiO ₂NH ₂O, and ferriferous oxide is dissolved into iron(ic) chloride and ferrous.The muriate of iron and other impurity in sour suspension for example, by centrifugal or remove by filter, or are done the better acid of further processing to retrieve to react.Undissolved amorphous titanium oxide water cleans with the further removal of impurity.From water, reclaim TiO with filtration or centrifuging then ₂After finishing, this step obtains white cake product.

Be sure of at TiO ₂Iron contamination in the pigment is the reason that causes non-white pigment.At TiO ₂Fe content should be less than 520ppm to be lower than 200ppm then better in the pigment.

Amorphous TiO ₂Calcined 30-60 minute down at 800 ℃-1000 ℃, make TiO ₂Change into the red metal and stone form of crystalline.Down heating 30-60 minute is more desirable at 875 ℃-925 ℃, because can reduce the undesirable variable color of product like this, and lower temperature can not be transformed into desirable crystallization shape to product effectively.

The red metal and stone of the crystallization that after calcining, obtains (rutile) product, though needle-like or granular, if serious caking can be pulverized or sand milling.For the last granularity of needle-like product is the 0.05-0.3 micron thickness, and the 0.1-1.0 micron is long, and about 0.2 micron thickness and 0.7 micron long are then more desirable.As opalizer, its quality depends on the optimum size scope that it is narrow.

When the red metal and stone of crystallization (rntile) product when being granular, its TiO ₂Mean particle size better less than about 1 micron and 0.3 micron.

TiO ₂Product can be used for just as an illustration, but not limiting to scope of the present invention in any typically used as Opacifying pigment, the TiO that obtains with the present invention ₂Pigment can be used as paint, the opalizer of paper and plastics (opacifier).The light shielding ability of product and whiteness decide by measuring diffusing coefficient of its light and reflectivity.Its light of product that obtains by the present invention looses coefficient greater than 2000cm ²/ g, the desirable 400cm that is higher than ²/ g, the preferable 9000cm that is higher than ²Its whiteness of/g records the result according to the method in example 1 and 12 and is higher than 80%, and preferable is 85-93%.

Following example is as explanation of the present invention, but the present invention is not limited thereto.

Example 1

With the breeze that the 600g sledge mill is crossed, the about 75 μ m of granularity contain the TiO of 70% weight ₂Impurity with 30% is scattered in the 450ml water.Breeze in the suspension is the shot sand milling 120 minutes of 1.5mm with the 800ml diameter, and rotating speed is that per minute 1000 changes.Used sand milling is a vertical water-cooled laboratory sand milling, and this mill has an internal diameter 11.5cm, and the tubular stainless-steel grinding container of high 19cm has axle and two alternate 4cm by the air turbo driving, the impeller of the poly-amino methyl ethyl ester of diameter 8.5cm.4.4 meters of the peripheral velocity per seconds of impeller.Speed is by a smooth rotating speed knotmeter control.After sand milling is finished, the about 10 μ m of mineral powder granular maximum particle size, the about 5 μ m of mean particle size.After with the filter screen of a perforate 0.5mm shot being told, in suspension, add 240 gram anhydrous Na OH from slag suspension, and thorough mixing.Breeze and NaOH ratio are mixture 120 ℃ of following air evaporation dryings in tray of 100: 40.After the drying, smash the caking and the thing that is uniformly mixed, with the fraternal laboratory of weber mill S-500(Weber Brothers Lab Mill S-500) the dried material of sledge mill.The fine powder that obtains in the porcelain crucible, in air ambient, 820 ℃ of following roastings 2 hours.The baked material of 150g grinds the caking that forms after the roasting to remove in mortar, be scattered in then in the 350ml water.Calcining matter and water are 1000rpm with 30 minutes rotating speeds of granulated glass sphere sand milling of 700ml diameter 1.2mm.In this sand milling step, replace shot to avoid drawing bad material variable color with granulated glass sphere.

Sieve remove granulated glass sphere after, the dispersion thing of roasting material that the centrifugation sand milling is crossed and water.Solid residue after centrifugal by the water redispersion and again centrifugal treating wash.Twice of repeated washing.

The gained solid dispersed is being filled about 100 ℃ of 1000ml() in the open cup of 6NHCl,, and stirred 90 minutes with magnetic stirrer about 100 ℃ of boilings.The centrifugal solid acid solution that contains.Solid washing twice is then at 120 ℃ of air dryings.The exsiccant solid was calcined 1 hour down at 900 ℃.

The density of the white product after the calcining is 4.14g/cm ³, X diffraction analysis result shows that calcinate has red metal and stone structure.Transmission electron microscope results proves pigmentary TiO ₂Particle has acicular structure.The granularity of acicular structure pigment is thick at 0.05 μ m-0.3 μ m, the scope that 0.1-1.0 μ m is long.

Smoke MgO with what luminous reflectance recorded ₂Surface albedo is 100% for standard, (the R of degree certainly of this pigment ^∞) be 88.4%, its scattering coefficient is 6,835 square centimeters of every gram (cm for (S) ²/ g).Fe content in the pigment is with the X-fluorescence spectrometry, and the result is 520ppm.

Scattering coefficient (S) and whiteness (R ^∞) mensuration.

TiO ₂The major function of pigment be for some material as: paint, paper and plastics etc. provides opaqueness, pigment is dispersed in this material.In much in order to the mode of describing the light tight ability of pigment, scattering coefficient has more practical significance and is the parameter of accurate easily and replication.

The principle of this method is that skim pigment is coated on the welding glass plate so that this film light transmission slightly, promptly have thick, the 80-90% of full black film reflectivity.Same dispersion thing film is coated on the white glass plate, and film will be coated with to such an extent that so thickly do not change its luminous reflectance factor so that increase film thickness again.(R and R behind the reflectivity of measuring this two film respectively ^∞), measure the weight (W) that is coated on the blackboard film, (every square centimeter of dry film is heavy, g/cm ²), can calculate optical scattering coefficient (S) according to the Kubelka-Munk light scattering theory.（Zeitschrift fur Tech，Physik，12，593，1931）。The reflectivity R of the film on the white glass plate ^∞Be commonly referred to whiteness.Can be according to the table that the Rubeka-Munk equation is formulated at article " New Graph for Conputing Scattening Coefficrenf and Hiding power " (the Official Digesf of Mitton-Jacobsen, Septemben, 1963, Pagco 871-913) finds in.Know R, R ^∞Behind W, the table of using above is easy to calculate S.Further specify the method for measuring S among the routine A down.

Example A

In water and add a little binder, this tackiness agent forms thing and prepares adhesive film as film in the time will disperseing thing to be coated onto to survey reflectivity on the sheet glass with colo(u)rant dispersion.Because the opaqueness of film is very responsive with the ratio of tackiness agent to pigment, thus this ratio should accurately be fixed, and remain on sufficiently high ratio so that obviously do not reduce the light shielding ability of pigment because of the existence of tackiness agent.Test is 70%(PVC in pigment volume concentration (PVC)) (pigment volume is 70% of a total solids volume, totally=pigment volume+tackiness agent volume) and enough low solids content under carry out, like this in the film that on welding glass, is coated with out with 37 μ m film spreaders light transmission slightly, (reflectivity only is the 80-90% of the complete black thick film of same dispersion thing).Solid volume about 4% is for TiO ₂Dispersion liquid is suitable, (pigment volume+tackiness agent volume=4% dispersion liquid cumulative volume).In order to measure S and R ^∞TiO ₂The example of the composition of pigment film illustrates in following table.(table is seen the literary composition back)

(1) a kind of anionic polyacrylamide dispersion agent, vending articles are called NalCO2324, and Nalco chemical company produces.

(2) carboxylic acid butadiene-styrene latex, commercially available " Dow Latex 620A " DOW chemical company produces.

In the above-mentioned composition, PVC=70.00%, the volume of dispersible solid=4.00%.

Pigment, water and dispersion agent mixed 5 minutes in the pressure-even pulp crusher of selling with " PT-45/80Brikmamm Homogeniger " trade(brand)name that Brikman instrument company produces, and speed places 4 grades.Add DOW Latex 620 glue then, under 2 grades speed, stirred this mixture 5 minutes.

With a wide 15cm, opening 0.037mm " bird formula film spreader (Bird Film Applicator) can obtain from Gardner laboratory commerce, (branch of Pacific Scientific Company).Place the top edge of piece 50 * 50cm welding glass plate (reflectivity=0), about 30ml dispersion liquid is placed on the front of spreader, spreader evenly is coated with on sheet glass with a steady speed.The film water placing flat is at room temperature dry.The bird formula spreader that with an opening is 75 μ m is coated in (reflectivity=85.6) on the white glass with same dispersion liquid.

Treat that film after dry about 2 hours, is 32cm with an area ², promptly the rectangle template of 5 * 6.25cm is put on the film of welding glass plate, and wipes off with the sword of the scraper coating that template is outer, stays on the black glass plate-32cm ²Rectangular membrane.Measure the reflectivity that is coated in film on welding glass and the white glass with a photoelectric reflection instrument then, reflectometer have an external digital voltmeter (DVM) and a wavelength be 457nm be the search unit of colour filter, these spectral filter commodity are called Wratten filter, and Eastman Kodak Company makes.Then the rectangle diaphragm on the welding glass plate is taken off with doctor edge, on analytical balance, weigh.

Following numerical value is represented an example:

R＝79.5

R ^∞＝92.0

W＝0.0186g/32cm ²or0.000577g/cm ²

Table 8 from 895 pages of above-mentioned Mitton-Jacobser article and above the R and the R that provide ^∞Value learns that scattering power (SW) is 4.09.Scattering coefficient (S) is calculated as follows:

S＝ (sw)/(w) = 4.09/(0.000577g/cm ²) =7088cm ²/g

Example 2

To contain the 70%TiO that has an appointment ₂As described in example 1, carry out sand milling with the Sorel slag 600g of 30% impurity.The suspension that this shot grinds contains 57% slag.Get above-mentioned suspension of 175g (containing the 100g solid slag approximately) and 67g anhydrous Na ₂CO ₃Mix drying, sledge mill and 1050 ℃ of following roastings 2 hours.In mortar hard calcining matter is ground into the 3.6mm size, sledge mill becomes fine powder then, makes further sand milling as example 1 way with granulated glass sphere at last.

As example 1 method, calcining matter is scattered in the water, centrifugation is cleaned, and with 1000ml 6N HCl digestion 90 minutes, next tells solid and cleaning.Calcining is after 1 hour down at 900 ℃, and obtaining having red metal and stone structure and density is 4.10g/cm ²White pigment.The whiteness of pigment is 78.3%, and S is 4.128cm ²/ g.

Example 3

As example 1 method, 70%TiO will be contained approximately ₂The slag of crossing with the sledge mill of about 30% impurity carries out sand milling with shot.The shot that leaches washes with water, and washing water and slag suspension merge, and add water and make suspension contain 45.9% solid.

327g slag suspension (=150g solid) is mixed with 52.5g anhydrous Na OH, and this moment, slag/NaOH ratio was 100: 35.Mixture is dry under 120 ℃, and sledge mill is then 800 ℃ of following roastings 2 hours.No longer further sand milling is in water, centrifugal with baked dispersion of materials.Isolated solid water disperses centrifugal treating twice repeatedly.The calcining matter of washing was boiled 1 hour with 1000ml 6N HCl in an open cup.After the acid solution digestion, tell twice of solid and centrifuge washing.With the solid redispersion in 300ml water and with 700ml granulated glass sphere sand milling 60 minutes under the 1000rpm rotating speed.After telling granulated glass sphere, white, opaque suspension mixes with isopyknic 12NHCl in an open cup and boils 10 minutes (about 108 ℃ of final boiling point).The solid of telling then washes with water twice and is dry down at 120 ℃.Solid was calcined 1 hour down at 900 ℃.Obtaining density at last is 4.0g/cm ³, iron level is the TiO of 150ppm ₂Pigment.The whiteness of this pigment is 88.9%, and S is 3.760cm ²/ g.

Example 4

Will be by the slag suspension 327g(=150g solid slag that grinds with shot of example 3 methods preparations) mix (slag/NaOH ratio is 100: 30) with 45g anhydrous Na OH.120 ℃ in mixture is dry down, presses the method sledge mill and the roasting of example 3 then.Two sour digestions of step and another are handled the step and are also finished by example 3 methods.This example is to join the influence of the amount of the NaOH in example 3 slags to last pigment products character in order to measure to reduce.

After the calcining, obtain lurid TiO ₂Pigment, wherein Fe content is 8300ppm.The whiteness of this pigment is 50%, S value undetermined.

Example 5

Contain about 70%TiO ₂It is (Slag/NaOH=100/40) in 50% the NaOH solution that the slag 600g that crosses with the sledge mill of 30% impurity is dispersed in 450g concentration.With this suspension use-case 1 described sand milling, use the 800ml shot, sand milling is 150 minutes under rotating speed 900rpm, makes the solid particulate mean particle size in the sand milling suspension be about 7 μ m, the big 13 μ m that reach.

After telling shot, suspension in 120 ℃ down dry, sledge mill 850 ℃ of following roastings 2 hours then.

The 150g calcining matter is with 700ml granulated glass sphere and 350ml water sand milling 10 minutes under the 1000rpm rotating speed.Leach behind the granulated glass sphere solid centrifugation and washed twice.The centrifugal solid dispersed that goes out is in the hydrochloric acid of 500ml10.8N, and 107 ℃ of following reflux 25 minutes.Centrifugally from acid solution tell solid and wash with water 1 time.The centrifugal solid that goes out heavily is scattered in 500ml7N HCl and refluxed 30 minutes at 108 ℃.Centrifugally from acid solution tell solid and wash three times.The dry down and 900 ℃ of calcinings 45 minutes down of 120 ℃ of centrifugal solids that goes out.The TiO that obtains ₂Pigment iron content 65ppm, whiteness 90.5% and S are 4.472cm ²/ g.

Example 6

Contain TiO ₂About 70% and the sledge mill of 30% impurity after slag 400g be scattered in 280mlH ₂(Slag/NaOH=100: 45) among O and the 180g anhydrous Na OH.Sand milling is at rotating speed 1350rpm in the suspension use-case 1, and sand milling is 150 minutes under the 1.5mm shot 600ml condition.

Tell shot, 120 ℃ of suspension that sand milling is crossed are dry down, sledge mill, and 840 ℃ of following roastings are 2 hours then.The 150g calcining matter is scattered in the 350ml water, under 1000rpm, and the granulated glass sphere 700ml sand milling of usefulness 1.2mm diameter 10 minutes.Leach granulated glass sphere, suspended substance is centrifugal, washs 2 times.Lay equal stress on 234g and contain 96gH of this filter of washing ₂O.The solid yield crossed of roast is 138g like this.With this and be scattered among the HCl of 300ml water and 605ml12N, liquid portion is 7.3N HCl, is become 6N by in the solid and back acidity.20 minutes centrifugal solids of telling from acid solution of 108 ℃ of following backflow digestions, the washing secondary and then is dispersed among the 600ml6N HCl, digestion 20 minutes, then centrifugation and washing 2 times.120 ℃ of down dry these solids, and calcined 1 hour under 900 ℃.The TiO that produces ₂Pigment contains Fe30ppm, and whiteness is 90.1%, and the S value is 6,170cm ²/ g.

Example 7

Slag/NaOH ratio becomes 100/50 and by following processing in this example:

Contain 70%TiO approximately ₂Slag 600g with behind the sledge mill of 30% impurity is scattered in 400mlH ₂Among the O and the sand milling in the use-case 1, with the shot 800ml of diameter 1.5mm, sand milling 120min leaches shot under the 1800rpm.

Add 60g anhydrous Na OH in the scoriaceous 200g slag of the 120g suspension toward containing, in 120 ℃ baking oven, be placed in the tray dry.After the drying, sledge mill and 840 ℃ of following roastings 2 hours.Calcining matter is scattered in the 350ml water, with the granulated glass sphere 700ml of diameter 1.2mm, and under 100rpm, sand milling 10 minutes.Leach granulated glass sphere, the calcining matter that sand milling the is crossed B filtration under diminished pressure of diameter 15cm, used filter paper hole 7 μ m, Britain WSR Bolton, Ltd company makes, and trade(brand)name " Whatman Filter Paper No.541 " is washed with about 2 premium on currency then.The calcining matter of washing 1000ml6N HCl, 108 ° of digestions in 20 minutes that reflux down.First flocculant solution that adds 7g1% then.First flocculation agent is a cationic homopolymer, is produced by Dow chemicol Compary, and this model is in U.S. Patent No. 3,719, general narration is arranged in 748.Through the suspension filtration under diminished pressure of flocculation, and use 21H ₂O washes on filter.Filter cake is scattered among the 1000ml6NHCl at 30 ℃, and heating makes temperature slowly be raised to 108 ℃ of boiling points (in about 20 minutes) and kept 20 minutes then.The 2nd flocculant solution that adds 1000ml cold water and 7g1% then.This flocculation agent also is that Dow chemicel Compang company produces, and is the anionic homopolymers of acrylamide, and solid-state cake has 1～5% hydrolysis.0.5% aqueous solution of second flocculation agent is at pH=3, and the viscosity under 25 ℃ is in 31-50 centipoise (CP) scope.Flocculated suspension thing filtration under diminished pressure is used 21H ₂O washes and is dry under 120 ℃, and the gained solid was calcined 1 hour down at 900 ℃.

Electron microscope picture shows that this product has needle-like and granular shape, and X-diffraction analysis result shows that this pigment is red metal and stone structure.The S value is that 2408cm/g and whiteness are 83.9%.

Example 8

In this example, produce TiO with the titanium-containing materials that is called muriate slag (Chloride Slag) ₂Pigment wherein contains the 85%TiO that has an appointment ₂With about 15% impurity.This material is granular, the about 840 μ m of granularity.

This raw material of 400g and 200g anhydrous Na OH and 300mlH ₂O mixes.Sand milling in the use-case 1, with the 1500rpm rotating speed, 700ml, the shot of diameter 1.5mm grind and made its average particle size be lower than 10 μ m in 240 minutes.From suspension, leach shot, 120 ℃ of dry down, sledge mills, and 840 ℃ of following roastings 2 hours.

The 150g calcining matter is scattered in 350mlH ₂O also uses the 700ml granulated glass sphere, and sand milling is 10 minutes under the 1000rpm.Leach granulated glass sphere and centrifugal suspended substance.Centrifugal cake washing 4 times.Centrifugal cake in 1000ml6NHCl, 108 ℃ of following backflow digestions 20 minutes.When digestion finishes, first flocculant solution in the example 7 of 5g1% is added in the digestion thing, decompression leaches suspended substance, and washes filter cake with 1000ml.Filter cake after washing is for the second time at 1000ml, among the 6NHCl, and 108 ℃ of following backflow digestions 20 minutes.After the digestion, add second flocculation agent of addressing in the 5g1% example 7.Suspended substance filtration under diminished pressure after the flocculation is also used 21H ₂O washes.Filter cake is dry under 120 ℃, calcined 1 hour down for 900 ℃.Gained TiO ₂Pigment S is 5.670cm ²/ g, whiteness is 89.0%.

Example 9

Contain 78%TiO approximately ₂The slag 500g that crosses with the sledge mill of 22% impurity is scattered in 350mlH ₂Among the O and the sand milling addressed of use-case 1, use 800ml, the shot of 1.5mm, sand milling is 180 minutes under the 1800rpm rotating speed.The circumference of impeller linear velocity is 8m/s.

The sieve of slag after the grinding by 425 μ m is to remove shot.Wash shot with water, and washing water are incorporated into the solid that makes slag suspension in the slag contain and reach 24.5% at last.

(=150g solid slag) adds 67.5g anhydrous Na OH in 612g slag suspension, makes slag and NaOH ratio reach 100/45 in a tray, 120 ℃ of following dry said mixtures.The dry thing of sledge mill is to obtain uniform fine powder.In porcelain crucible, add this powder of thermal bake-out 150 minutes then under 840 ℃.Promptly in mortar, grind calcining matter after the cooling.Then calcining matter is scattered in 350mlH ₂Among the O, with the granulated glass sphere of 700ml diameter 1.2mm, sand milling is 10 minutes under the 1800rpm.The sand milling calcining matter sieves and tells granulated glass sphere, and with using 15cm B filtration under diminished pressure after the dilution of 1500ml water, filter paper is Whatman No.541.The about 21H of the filter cake of thick about 2cm ₂O washes.The solids content of filter cake about 62.6%.

Filter cake after washing is scattered in 300mlH ₂Among O and the 200ml12NHCl.The mixture of the about 4.4N of acidity put into one 21 4 mouthfuls burn and, one of them is equipped with reflux condensing tube, one be thermometer, one be agitator, another is a funnel of being with valve.To disperse thing to be heated to 100 ℃, and add 400ml12NHCl then and make acidity be increased to 6N, this moment, temperature can temporarily drop to 85 ℃, and temperature is raised to 108 ℃ after 5 minutes, and this is the boiling point of 6NHCl.Boiled 20 minutes, and be diluted to 21 with cold water then.Under continue stirring, 1% the first flocculant solutions that add that 7g example 7 addresses are in mixture.

Filter the mixture of the about 3N of acidity, use 21H ₂O is the filter wash cake on filter.Filter also contains 32.5% solid approximately.

With filter cake, heavy 323g(=105g solid) is scattered in and contains 280mlH ₂O adds in the 200ml12NHCl solution.This mixture changes in the 4 neck bottles and is heated to 100 ℃, adds the HCl of 300ml12N then.Make temperature be raised to 108 ℃ of 6NHCl boiling temperatures and kept this temperature 20 minutes.With cold water with mixture towards rare to 21, under constantly stirring, add second flocculation agent addressed in the example 7 of 7g1% in mixture.As a spline filter and purging compound after the digestion first time.

About 3cm is thick for filter cake, and 120 ℃ dry down, grinds in mortar then.Grinding back 900 ℃ calcined 1 hour down.At once it is changed over to after the calcining to be exposed under the air room temperature in the big shallow porcelain dish and cool off.Obtain TiO ₂Pigment.

The X-diffraction analysis proves that this pigment is rutile structure, and its density is 4.1g/cm ³, whiteness is that 92.2% crystalline form is a needle-like.

Example 10

Except slag/NaOH ratio become 100/40 and before sand milling, just add add behind NaOH rather than the sand milling, TiO ₂The preparation of pigment such as example 9.

The S of this needle-like pigment is 8.900cm ²/ g and whiteness are 91.0%.

Example 11

Used initial feed is to analyse the titanium-containing materials of preparation from ilmenite through pulverizing roasting and follow-up HCl drop in the Benilite circulation technology in this example.This black material contains 93%TiO approximately ₂With 7% impurity.Its granularity is about 250 μ m.

400g above-mentioned raw materials and 200gNaOH and 350mlH ₂O mixes the sand milling of addressing in the use-case 1 of back, uses 600ml, the shot of 1.5mn, and sand milling is 90 minutes under the 1600rpm.Mill back material particle size average out to 10 μ m.After leaching shot, 120 ℃ down dry, sledge mill and 840 ℃ of following roastings 2 hours.The 170g calcining matter is scattered in the 350ml water and uses the 700ml granulated glass sphere, and sand milling is 10 minutes under the 1600rpm.Leach granulated glass sphere, centrifugal suspension, centrifugal filter cake wash with water twice.Centrifugal filter cake is backflow digestion 20min in 1000ml6NHCl.From acid solution, tell solid and centrifuge washing.With centrifugation and cleaning after the digestion for the second time of 1000ml6NHCl do.120 ℃ of following drying solids, 900 ℃ of following calcinings obtain needle-like TiO then ₂Pigment.This pigment S is 4.260cm/g, and whiteness is 90.0%.

Below table 1 summarized above each routine result except that example 2,8,11.(table is seen the literary composition back)

Example 12

From a QIT-FER ET TIYANE of Canada Company, 1NC., its granularity of slag powders sample that obtains is about 74 μ m.Getting 1200g sample and 480gNaOH, the 1000ml diameter to be arranged in being added to be in the sand milling of 1.2mm shot and 1000ml water, and the straight slag maximum particle size of this mixture of sand milling (the granularity upper limit) is 10 μ m then.Slag/NaOH weight ratio is 100/40, leach behind the shot dry in 100 ℃ stove, the caking of sledge mill when smashing drying then.

The sledge mill material was 875 ℃ of following roastings 2 hours.The caking that calcining matter is formed when smashing roasting by a pulverizer is then in about 700mlH ₂Zirconium oxide bead with 1 liter of 1.2mm diameter among the O carried out sand milling 5 minutes.Leach globule, the filtration under diminished pressure suspended substance also washes filter cake twice with water, and 1 premium on currency is used in each washing approximately.

194g calcining matter 1000ml6N hydrochloric acid (HCl) digestion by dry measure calculating.Digestion step is as follows: 6N solution (calcining matter/acid mixture) temperature is room temperature (20 ℃), slowly is warmed up to the boiling temperature of 6N acid then with about 5 ℃/minute speed, and refluxes 15 minutes.H when calculating the HCl equivalents in the wet cake ₂O content should count.The flocculation agent SEPARANMG-205(DOW Chomical Company production of 3g1%) solution adds in the digestion suspension.Filter suspended substance and wash twice, H is used in each washing approximately ₂The O1 liter.Again filter cake is scattered in the water,, carries out the digestion second time, in suspension, add flocculation agent with the equal amts of digestion for the first time with 800ml6N HCl as the same procedure of the digestion first time.Filtration under diminished pressure suspended substance and washing.About 3 hours of 110 ℃ of following dry cakes.Calcined 1 hour down for 900 ℃ then, the rutile pigment that obtains at last has the exemplary particles shape.

The method of measuring the extra dry white wine degree of calcined material is with the part material diameter 2.5cm that packs into, measures its reflectivity in the dark sample cap of 1.3cm and with the photoelectrometer that blue spectral filter is housed.Instrument is that 86.9% white standard sheet is calibrated with known whiteness under the blue spectral filter condition is arranged at first.The extra dry white wine degree of this example calcined material is 88.0%.

The scattering coefficient of calcined material is measured by following method:

15g pigment and 1/2g tripoly phosphate sodium STPP are put into 70ml water, disperse 5 minutes with the high speed dispersion device.Stirred 3 minutes in the commodity that 3.1gRohm and Hoas CO. is produced Rhoplex B-100 latex by name and the 1/2gTriton X-100 tensio-active agent adding dispersion liquid and with have gentle hands then.Dispersion liquid is coated in (E.I.Dupont de Nemours﹠amp on the thick clean Mylor plastic sheet of 50 μ m with-37 μ mBird film spreaders; Trade mark) and place 100 ℃ of bakings of a baking oven 3 minutes Co..Get the Mylor diaphragm that was coated with of 5 * 5cm and weigh, be placed on one then and scribble on the flat black slab glass of 5 * 12.5cm of propylene glycol.Being coated with propylene glycol is in order to ensure its optics contact.With the sample reflectivity R on the photoelectrometer mensuration welding glass _BCoating on 5 * 5cmMylro film is washed off, and dry Mylar film is also weighed to calculate the coating wt W on the unit surface.The approximation R of complete opaque coating ^∞Can be by measuring as laxative remedy: sample is coated on the Mylar diaphragm of 50 μ m, drying repeats the reflectivity that this step measures up to photoelectrometer and reaches maximum value.Utilize R _B, R ^∞With the W value, use article " New Graphs for Conputing Scattering Coelficeerf and Hiding Power " (the fficial Digesf of Mitton-Jocbsen again, Septermber 1963, Pages 871-913) in table find out scattering power SW value.Scattering coefficient S is calculated as follows then:

S＝ (SW)/(W)

In this example, the scattering coefficient of calcined material is 3.336cm ²/ g.The ion-coupled plasma body spectrometry of iron level in the calcined material, iron level is 200ppm in this example.

Table A

Weight density solid volume dispersion liquid volume

（g） （g/ml） （ml） ml

TiO ₂Pigment sample 15.00 4.20 3.57 3.57

Nalco2324 0.50 1.00 0.50

Dispersion agent (1)

Dispersing binder (2) 3.06 1.04 1.53 3.11

（50.1%

Gu solid is heavy)

Water 120.32 1.00-120.32

138.88 5.10 127.50

Claims (11)

1, a kind of preparation TiO ₂The method of pigment, this method may further comprise the steps:

(a) raw material that will contain titanium dioxide becomes the particle of diameter 0.5 to 3mm size in grinding machine for grinding;

(b) raw material that will contain titanium dioxide mixes with alkali metal compound, and alkali metal compound is selected from alkali-metal oxyhydroxide, carbonate and oxide compound; The raw material that wherein contains titanium dioxide is 100 with the ratio of alkali metal hydroxide: 30-100: 60 (by weight).

(c) after step (a), the mixture that will contain the raw material of titanium dioxide and water grinds to form the particle less than 15 μ m, or after step (b), and the mixture that will contain the raw material of titanium dioxide and alkali metal compound and water grinds to form the particle less than 15 μ m.

(d) at 700 ℃ of-950 ℃ of these mixtures of roasting;

(e) this calcining matter of digestion 10-20 minute in hydrochloric acid; With

(f) solid that obtains in the digestion step is calcined down to generate TiO 2 pigment at 800 ℃-1000 ℃.

2, contain TiO according to the process of claim 1 wherein ₂Raw material be selected from Sorel slag (Sorelslag), the ilmenite and the muriate slag of rich choosing, alkali metal compound is an alkali metal hydroxide.

3, according to the method for claim 2, wherein containing the titanium dioxide raw material is the Sorel slag, and alkali metal hydroxide is a sodium hydroxide, and their mixture is worn into particle less than 10 μ m at the sand mill medium sand.

4, according to claim 1,2 or 3 method, be included in step (c) after, from the mixture of roasting, leach dissolved material, and the step that continues (e) after-filtration goes out hydration, the atypic titanium dioxide raw material that is generated by sour step.

5, according to claim 1,2 or 3 method, the roasting mixture that is included in 90 ℃-110 ℃ digestion step (e) in hydrochloric acid with form hydration, amorphous titania pigment, and before calcining the step of this titanium dioxide raw material of washing.

6, according to the method for claim 5, wherein the digestion time to the roasting raw material is 10 to 40 minutes.

7, according to claim 1,2 or 3 method, it comprises when particle when being granular, the product of roasting micro mist is changed into the step that mean particle size is 0.3 μ m.

8, according to claim 1,2 or 3 method, it comprises when product is needle-like, and the product of roasting micro mist is changed into the long and thick particulate step of 0.05-0.3 μ m of 0.1-1.0 μ m.

9, according to the method for claim 1, it comprise with less than 5 ℃ of/minute clock rate heating calcining matter/acid mixtures to the boiling point between their 90 ℃-110 ℃ to form the step of meal.

10, according to the method for claim 1, it comprises such step: heating calcining matter/acid mixture is to their boiling point, during heating, keep the acidity of calcining matter/acid mixture to be lower than 4w, when temperature surpasses 90 ℃, the acidity of calcining matter/acid mixture increases to 6N, forms the needle-like product thus.

11, according to the method for claim 1,2 or 3, wherein digestion step is carried out secondary at least.

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