JP2007055875A - Method for improving filtration speed of aqueous titanium oxide slurry and titanium oxide powder obtained thereby - Google Patents
Method for improving filtration speed of aqueous titanium oxide slurry and titanium oxide powder obtained thereby Download PDFInfo
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Abstract
Description
本発明は、酸化チタンの水性スラリーの濾過速度を改善する方法およびこの方法を使用して得られた酸化チタン粉体に関する。 The present invention relates to a method for improving the filtration rate of an aqueous slurry of titanium oxide and to a titanium oxide powder obtained using this method.
酸化チタンは、白色顔料として塗料、プラスチック、ゴム、インキ、トナー、化粧品、食品、医薬品などに使用されている。微粒子酸化チタンは紫外線ブロッカーおよび光触媒としての用途を有する。これらの用途に応じ、酸化チタンは、様々な形晶形（ルチル形またはアナタース形）、粒子形状、一次および二次粒子径、粒度分布、表面特性を持つものが用いられる。どのような製造法によるにせよ、酸化チタンの製造工程は、不純物を除去するため酸化チタンを水に懸濁してスラリーとし、濾過し、洗浄する工程を必ず含んでいる。酸化チタンの一次粒子の大きさは一般にサブミクロンまたはナノメーターのオーダーであり、かつ親水性であるため、水中で水和して親水コロイドに似た性質を示す。スラリーに含まれるこのような性質を示す粒子の量が多ければ多い程濾過速度が遅くなる。また、例えば医薬品用、食品用、化粧品用添加物としての酸化チタンは、有害重金属含量が定められた許容値以下であることが求められるため、硫酸のような無機酸を加温したスラリーへ添加し、溶出により重金属を除去する処理を必要とする。この処理は親水コロイドの性質を示す粒子の量を増加させ、濾過に要する時間を一層長くする。さらに最終用途によっては、出荷した酸化チタン粉末が白濁することなく水中で速やかに沈降する性質が求められる。本発明は、酸化チタンスラリーの濾過速度を早める方法を提供する。 Titanium oxide is used as a white pigment in paints, plastics, rubbers, inks, toners, cosmetics, foods, pharmaceuticals, and the like. Fine particulate titanium oxide has uses as an ultraviolet blocker and photocatalyst. Depending on these applications, titanium oxide having various crystal forms (rutile form or anatase form), particle shape, primary and secondary particle diameter, particle size distribution, and surface characteristics are used. Regardless of the manufacturing method, the manufacturing process of titanium oxide always includes a process of suspending titanium oxide in water to form a slurry, filtering, and washing in order to remove impurities. The size of the primary particles of titanium oxide is generally on the order of submicron or nanometer and is hydrophilic, so that it hydrates in water and exhibits properties similar to a hydrocolloid. The greater the amount of particles exhibiting such properties contained in the slurry, the slower the filtration rate. In addition, for example, titanium oxide as an additive for pharmaceuticals, foods, and cosmetics is required to have a harmful heavy metal content not more than a predetermined allowable value, so it is added to a slurry in which an inorganic acid such as sulfuric acid is heated. In addition, it is necessary to remove heavy metals by elution. This treatment increases the amount of particles exhibiting the properties of a hydrocolloid and further increases the time required for filtration. Furthermore, depending on the end use, the shipped titanium oxide powder is required to have a property of quickly settling in water without becoming cloudy. The present invention provides a method for increasing the filtration rate of a titanium oxide slurry.
本発明は、酸化チタンの水性スラリーへ、酸化チタンに対してカルシウムとして少なくとも０．０３重量％のカルシウムイオン源を添加することを特徴とする酸化チタン水性スラリーの濾過速度を改善する方法を提供する。 The present invention provides a method for improving the filtration rate of an aqueous titanium oxide slurry, characterized in that at least 0.03% by weight of calcium ion source is added as calcium to the titanium oxide to the aqueous titanium oxide slurry. .
他の面において、本発明は、ＣａＯに換算して少なくとも０．０４重量％の結合したカルシウムを含有し、白濁することなく水中で少なくとも１時間以内に沈降する酸化チタン凝集粉体を提供する。 In another aspect, the present invention provides a titanium oxide agglomerated powder that contains at least 0.04% by weight of bound calcium in terms of CaO and settles in water for at least one hour without becoming cloudy.
塩化カルシウムなどのカルシウムイオン源化合物は、例えば豆腐の凝固剤として使用されている。これは良く知られた多価金属イオンのコロイドの凝集作用を利用したものであり、同じ原理は有機凝集剤と併用して上水道水、下水、工場排水などから浮遊物質（ｓｓ）をフロックに凝集し、除去するために利用されている。しかしながらこれらの処理は水の浄化が目的であり、凝集物は廃棄処分されるのに対し、本発明の場合はこれと反対に懸濁している酸化チタン粒子が目的物であるから、回収される酸化チタンの品質を劣化させてはならない点で水の浄化と異なる。 Calcium ion source compounds such as calcium chloride are used as a coagulant for tofu, for example. This utilizes the well-known colloidal action of colloids of polyvalent metal ions, and the same principle is used in combination with organic flocculants to aggregate floating substances (ss) into floc from tap water, sewage, industrial wastewater, etc. And is used to remove. However, the purpose of these treatments is to purify water, and the aggregates are discarded. In contrast, in the case of the present invention, suspended titanium oxide particles are the target, and are recovered. It differs from water purification in that the quality of titanium oxide must not be degraded.
本発明において使用する酸化チタンは、その結晶形、粒子径、製造法を問わない。例えば結晶形はアナタース形、ルチル形、無定形を問わず、粒子径は公称粒子径が０．２〜０．４μｍの範囲にある顔料級酸化チタン、０．１μｍ以下の微粒子酸化チタン、および塩素法、硫酸法またはアルコキシドからゾルゲル法により製造された酸化チタンのいずれにも適用することができる。 The titanium oxide used in the present invention may be of any crystal form, particle size, or manufacturing method. For example, regardless of whether the crystal form is anatase, rutile, or amorphous, the particle size is pigment grade titanium oxide having a nominal particle size in the range of 0.2 to 0.4 μm, fine particle titanium oxide of 0.1 μm or less, and chlorine. The present invention can be applied to any of titanium oxide produced by the sol-gel method from the method, sulfuric acid method or alkoxide.
濾過速度はスラリー中の酸化チタン濃度に反比例して速くなる。スラリーへカルシウムイオンを添加しない場合に比較して、本発明によりカルシウムイオンを添加した場合はより高濃度のスラリーをより短時間で濾過することができる。１００〜５００ｇ／Ｌのスラリー濃度が使用できるが、特に２００ｇ／Ｌ以上の高濃度が効率的である。 The filtration rate increases in inverse proportion to the titanium oxide concentration in the slurry. Compared with the case where calcium ions are not added to the slurry, when calcium ions are added according to the present invention, a slurry having a higher concentration can be filtered in a shorter time. A slurry concentration of 100 to 500 g / L can be used, but a high concentration of 200 g / L or more is particularly efficient.
コロイドの凝結の場合、シュルツェ−ハーディの法則に従い、凝結作用は添加するイオンの価数の大きいものほど著しい。従って塩化アルミニウムまたは硫酸第二鉄のような３価の金属化合物の方が塩化カルシウムのような２価の金属化合物よりも凝結作用が大きいのであるが、これらは水溶液が強い酸性を呈すること、残留して酸化チタンを呈色させるなどの理由により本発明の目的には適してない。この点も本発明が水の浄化と異なる点の一つである。 In the case of colloidal condensation, according to Schulze-Hardy's law, the condensing action is more remarkable as the valence of the added ions increases. Therefore, a trivalent metal compound such as aluminum chloride or ferric sulfate has a larger coagulation effect than a divalent metal compound such as calcium chloride. Therefore, it is not suitable for the purpose of the present invention for the reason of coloring titanium oxide. This is also one of the differences between the present invention and water purification.
カルシウムイオン源、すなわち水溶性カルシウム塩のアニオンは任意であるが、経済性、濾液の再利用可能性、排水処理の容易性などを考慮して塩化カルシウムが好ましい。その添加量は、スラリー中の酸化チタンに対しカルシウムとして少なくとも０．０３重量％（３００ｐｐｍ）である。しかしながら濾過した後乾燥して得られる酸化チタンが不必要に多いカルシウム分を含むことになるので、０．２重量％（２０００ｐｐｍ）以上を添加する必要はない。好ましい添加量は０．０４重量％（４００ｐｐｍ）〜０．１２重量％（１２００ｐｐｍ）の範囲内にある。添加量は酸化チタンの粒子径にも依存し、濾過速度を促進する目的に対しては、上の範囲内で顔料級酸化チタンの場合は低く、微粒子酸化チタンの場合は高い添加量が選ばれる。例えば顔料級酸化チタンの場合約０．０３％、微粒子酸化チタンの場合約０．１％の添加量が好ましい。 The calcium ion source, that is, the anion of the water-soluble calcium salt is optional, but calcium chloride is preferred in consideration of economy, reusability of the filtrate, ease of wastewater treatment, and the like. The addition amount is at least 0.03% by weight (300 ppm) as calcium with respect to titanium oxide in the slurry. However, since titanium oxide obtained by filtering and drying contains an unnecessary amount of calcium, it is not necessary to add 0.2% by weight (2000 ppm) or more. A preferred addition amount is in the range of 0.04 wt% (400 ppm) to 0.12 wt% (1200 ppm). The amount of addition also depends on the particle size of the titanium oxide, and for the purpose of accelerating the filtration rate, within the above range, the pigment grade titanium oxide is low, and in the case of fine particle titanium oxide, a high amount is selected . For example, an addition amount of about 0.03% for pigment grade titanium oxide and about 0.1% for fine particle titanium oxide is preferable.
カルシウムイオン源の添加は１００〜５００ｇ／Ｌ、特に２００ｇ／Ｌ以上の酸化チタン濃度を有するスラリーに対して行なわれる。スラリーは、酸化チタンの製造過程にあるスラリー、または既製の酸化チタンから例えば重金属含量あるいは水可溶物（化粧品原料基準水可溶物試験法）を許容値以下に減らすため水あるいは塩酸、硫酸等の酸性水溶液下で処理し、濾過、洗浄して得られるウェットケーキのスラリーであることができる。スラリーは常温以上沸点以下の温度、特に６０〜９０℃に加温して置くのが好ましい。カルシウムイオン源の添加後、スラリーのｐＨをｐＨ約７．０に調節し、攪拌しながら１０分〜１時間熟成する。次に熟成したスラリーを濾過、洗浄し、ウェットケーキを乾燥、粉砕する。なお、濾過時には固液分離を促進させるため、減圧濾過を行っても構わない。 The calcium ion source is added to a slurry having a titanium oxide concentration of 100 to 500 g / L, particularly 200 g / L or more. The slurry is a slurry in the process of manufacturing titanium oxide, or water, hydrochloric acid, sulfuric acid, etc. to reduce the heavy metal content or water soluble matter (cosmetic raw material standard water soluble matter test method) to an allowable value or less from the ready-made titanium oxide. It can be a slurry of a wet cake obtained by treating under an acidic aqueous solution, filtering and washing. The slurry is preferably placed at a temperature not lower than the normal temperature and not higher than the boiling point, particularly 60 to 90 ° C. After the addition of the calcium ion source, the pH of the slurry is adjusted to about 7.0 and aged for 10 minutes to 1 hour with stirring. Next, the aged slurry is filtered and washed, and the wet cake is dried and pulverized. In order to promote solid-liquid separation during filtration, vacuum filtration may be performed.
このようにして得られる酸化チタン粉体は、酸化物および／または水酸化物の形で添加したカルシウムイオンの一部と結合して保持している。そのような酸化チタン粉体がＣａＯに換算してカルシウムを０．０４重量％以上含むときは水に再懸濁した時白濁せずに短時間で沈降する。このような性質を有する酸化チタンは、化粧品分野において例えばリキットファンデーション用として有用である。 The titanium oxide powder obtained in this way is bonded and held with some of the calcium ions added in the form of oxides and / or hydroxides. When such a titanium oxide powder contains 0.04% by weight or more of calcium in terms of CaO, it is settled in a short time without becoming cloudy when resuspended in water. Titanium oxide having such properties is useful, for example, for rekit foundations in the cosmetics field.
以下に限定を意図しない実施例および比較例により本発明を例証する。これらにおいて「％」は重量基準による。なお、金属成分の分析は、試料が液体の場合はＩＣＰ発光分光分析装置（リガク社製ＣＩＲＯＳ１２０）を、粉体の場合蛍光Ｘ線による定量分析装置（リガク社製ＺＳＸ１００−Ｅ）を用いた。 The invention is illustrated by the following non-limiting examples and comparative examples. In these, “%” is based on weight. In the analysis of the metal component, an ICP emission spectroscopic analyzer (CIROS 120 manufactured by Rigaku Corporation) was used when the sample was a liquid, and a quantitative analyzer using fluorescent X-rays (ZSX100-E manufactured by Rigaku Corporation) was used when the sample was a powder.
実施例１
酸化チタン（テイカ社製ＪＡ−Ｃ、平均粒子径：約０．２μｍ、結晶系：アナタース形）１２５ｇを１リットルのイオン交換水（液中の金属成分はいずれも０．３ｐｐｍ以下）に分散させた。このスラリーを８０℃に昇温し、そこに酸化チタンの固形分換算で０．０５〜０．１％にあたるカルシウム分となるように、塩化カルシウム６水和物をそれぞれ０．３５〜０．６９ｇ添加した。
Example 1
Disperse 125 g of titanium oxide (JA-C manufactured by Teica Co., Ltd., average particle size: about 0.2 μm, crystal system: anatase type) in 1 liter of ion-exchanged water (all metal components in the liquid are 0.3 ppm or less) It was. The slurry was heated to 80 ° C., and 0.35 to 0.69 g of calcium chloride hexahydrate was added so that the calcium content was 0.05 to 0.1% in terms of solid content of titanium oxide. Added.
添加した塩化カルシウムと、酸化チタンに対するカルシウム量について表１に示す。 Table 1 shows the added calcium chloride and the amount of calcium relative to titanium oxide.
表１
実験No． 添加した塩化カルシウム量 酸化チタンに対する
ＣａＣｌ ２ ・６Ｈ ２ Ｏ（ｇ） カルシウム量（％）
１−１ ０．３５ ０．０５（＝５００ｐｐｍ）
１−２ ０．４９ ０．０７（＝７００ｐｐｍ）
１−３ ０．５６ ０．０８（＝８００ｐｐｍ）
１−４ ０．６９ ０．１０（＝１０００ｐｐｍ）
Table 1
Experiment No. Calcium chloride added to titanium oxide
CaCl 2 · 6H 2 O (g) Calcium content (%)
1-1 0.35 0.05 (= 500 ppm)
1-2 0.49 0.07 (= 700ppm)
1-3 0.56 0.08 (= 800ppm)
1-4 0.69 0.10 (= 1000ppm)
上記スラリーに、硫酸もしくは水酸化ナトリウム水溶液を加えることにより、ｐＨを７に調整し、攪拌しながら３０分間熟成した。 The slurry was adjusted to pH 7 by adding sulfuric acid or an aqueous sodium hydroxide solution, and aged for 30 minutes with stirring.
熟成後のスラリーを濾過、洗浄し、得られたケーキを乾燥、粉砕した。
濾過には、ヌッチェを用い、濾紙はアドバンテック社製の定性濾紙２を用いた。また、濾過時には減圧濾過を行い、濾液回収側は、常圧の１０〜２０分の１に減圧した。
The slurry after aging was filtered and washed, and the resulting cake was dried and pulverized.
Nutsche was used for filtration, and qualitative filter paper 2 manufactured by Advantech was used as the filter paper. Moreover, it filtered under reduced pressure at the time of filtration, and the filtrate collection | recovery side was pressure-reduced to 10-20 times of normal pressure.
なお、洗浄には１リットルのイオン交換水を用い、濾過および洗浄の際にそれぞれ要した時間（濾液の滴下が目視されなくなる時間）も合わせて測定した。 In addition, 1 liter of ion-exchanged water was used for washing, and the time required for filtration and washing (the time when dropping of the filtrate was not visually observed) was also measured.
さらに、上記で得られた粉体について、凝集沈降性の評価を行い、カルシウム分を測定した。結果を表２に示す。 Furthermore, about the powder obtained above, the aggregation sedimentation property was evaluated and the calcium content was measured. The results are shown in Table 2.
比較例１
塩化カルシウムを全く加えない以外は、実施例１で記載したと同様の方法で酸化チタンを処理し、同様に評価を行った。結果を表２に実施例１と合わせて示す。
Comparative Example 1
Titanium oxide was treated in the same manner as described in Example 1 except that calcium chloride was not added at all and evaluated in the same manner. The results are shown in Table 2 together with Example 1.
凝集沈降性評価：
１００ｍＬ目盛り付メスシリンダーにイオン交換水１００ｍＬを入れ、そこに酸化チタン粉体０．３ｇを投入し、メスシリンダー上部にふたをし、往復転倒を３回行った後、１時間静置した。静置後の固形成分の沈降度合いについて、メスシリンダーの透明度を目安に目視にて観察した。
Aggregation sedimentation evaluation:
A 100 mL graduated cylinder was charged with 100 mL of ion-exchanged water, 0.3 g of titanium oxide powder was added thereto, the upper part of the graduated cylinder was covered, and the cylinder was reciprocally tumbled three times, and then allowed to stand for 1 hour. The degree of sedimentation of the solid component after standing was visually observed with the transparency of the graduated cylinder as a guide.
表２
実験No． 濾過時間（分） 目視による 粉体の
母液 洗浄液 メスシリンダー Ｃａ分
の状態 （％）
１−１ ７ ５０ 透明 ０．０５
１−２ ６ ４７ 透明 ０．０７
１−３ ６ ３７ 透明 ０．０８
１−４ ５ ３７ 透明 ０．１
比較例１ ３０ １５４ 白濁 ０．０１以下
母液：最初に濾過に用いるスラリー（１Ｌ）
洗浄液：母液濾過終了後加えたイオン交換水（１Ｌ）
透明：メスシリンダーを通して先が見える
白濁：メスシリンダーが白く濁り先が見えない
Ｃａ分：酸化チタンに対するカルシウムの比率（ＣａＯ換算）
Table 2
Experiment No. Filtration time (min) Visual inspection of powder
Mother liquid Cleaning liquid Measuring cylinder Ca
Status (%)
1-1 7 50 Transparent 0.05
1-2 6 47 Transparent 0.07
1-3 6 37 Transparent 0.08
1-4 5 37 transparent 0.1
Comparative Example 1 30 154 Cloudiness 0.01 or less
Mother liquor: First slurry used for filtration (1 L)
Washing liquid: ion-exchanged water (1 L) added after completion of mother liquor filtration
Transparency: White turbidity visible through graduated cylinder: graduated cylinder white and turbid not visible Ca content: Ratio of calcium to titanium oxide (CaO equivalent)
実施例２
投入する酸化チタンの量をそれぞれ５０〜５００ｇまで変化させ、それに対応して添加する塩化カルシウム量を酸化チタンに対するカルシウムの比率が一定（０．０５％）となるように変更する以外は、実施例１と同様の方法で処理を行った。
酸化チタンの濃度を表３に示す。
Example 2
Example except that the amount of titanium oxide to be added is changed from 50 to 500 g, and the amount of calcium chloride added correspondingly is changed so that the ratio of calcium to titanium oxide is constant (0.05%). The treatment was performed in the same manner as in 1.
Table 3 shows the concentration of titanium oxide.
表３
濾過時間（分）
実験No． 酸化チタン濃度（ｇ／Ｌ） 母液 洗浄液
２−１ ５０ ３ ２０
２−２ １００ ４ ２５
２−３ ２００ ５ ３０
２−４ ３００ ９ ３３
２−５ ４００ １０ ４６
２−６ ５００ １３ ５５
Table 3
Filtration time (min)
Experiment No. Titanium oxide concentration (g / L) mother liquor cleaning solution 2-1 50 3 20
2-2 100 4 25
2-3 200 5 30
2-4 300 9 33
2-5 400 10 46
2-6 500 13 55
実施例２においてそれぞれ得られた粉体について、上記凝集沈降性評価を行ったところ、いずれの場合も、目視によるメスシリンダーの状態は、透明であった。 The powder obtained in Example 2 was subjected to the above aggregation and sedimentation evaluation. In each case, the state of the graduated cylinder visually was transparent.
実施例３
〔使用する酸化チタンを、シリカで被覆処理（２５％）した微粒子酸化チタンとした場合〕
平均一次粒子径が１５ｎｍである微粒子酸化チタン（テイカ社製ＭＴ−１５０Ａ）１０００ｇを５リットルのイオン交換水に分散させ、スラリー化した。このスラリーを８０℃に昇温して撹拌しつつ、そこに、ＳｉＯ２換算で２００ｇ／リットルに調整したケイ酸ソーダ水溶液１２５０ｍｌと硫酸とを、ｐＨを中性付近に調節しながら同時に加えた。ケイ酸ソーダ水溶液添加終了後、ｐＨを７に調整し、３０分間撹拌・熟成した。このスラリーを（減圧）濾過することにより、酸化チタンに対し、重量換算でシリカを２５％被覆した微粒子酸化チタンのウェットケーキを得た。この濾過には２時間かかった。
上記ウェットケーキに再びイオン交換水５リットルを加えてスラリー化した後、塩化カルシウム１ｇ（酸化チタンに対し０．１重量％）を加えて撹拌した。このスラリーを３０分間熟成した後、減圧濾過を行った。固形分が得られるまで、２時間かかった。
Example 3
[When the titanium oxide used is fine particle titanium oxide coated with silica (25%)]
1000 g of fine particle titanium oxide (MT-150A manufactured by Teica) having an average primary particle size of 15 nm was dispersed in 5 liters of ion-exchanged water to form a slurry. While this slurry was heated to 80 ° C. and stirred, 1250 ml of a sodium silicate aqueous solution adjusted to 200 g / liter in terms of SiO 2 and sulfuric acid were simultaneously added while adjusting the pH to near neutrality. After the addition of the aqueous sodium silicate solution, the pH was adjusted to 7, and stirred and aged for 30 minutes. By filtering this slurry (reduced pressure), a wet cake of fine-particle titanium oxide coated with 25% of silica in terms of weight with respect to titanium oxide was obtained. This filtration took 2 hours.
After adding 5 liters of deionized water again to the wet cake to make a slurry, 1 g of calcium chloride (0.1 wt% with respect to titanium oxide) was added and stirred. The slurry was aged for 30 minutes and then filtered under reduced pressure. It took 2 hours until a solid was obtained.
比較例２
実施例３と同様の操作を行って、ウェットケーキを得た。このウェットケーキにイオン交換水５リットルを加えてスラリー化した後、塩化カルシウムを加えずに撹拌を続け、３０分間の熟成の後、（減圧）濾過を行った。２４時間濾過操作を続けたが、濾液が落ちることはなく、濾過操作ができなかった。
Comparative Example 2
The same operation as in Example 3 was performed to obtain a wet cake. The wet cake was slurried by adding 5 liters of ion-exchanged water, followed by stirring without adding calcium chloride. After aging for 30 minutes, filtration was performed (reduced pressure). The filtration operation was continued for 24 hours, but the filtrate did not fall and the filtration operation could not be performed.
実施例４
本実施例は重金属等の不純物を減らすために酸洗浄処理を示す。酸洗浄を行っていない酸化チタン（テイカ社製ＪＡ−Ｃ）１２５ｇを１リットルのイオン交換水に分散させスラリーを作成した。このスラリーを８０℃に昇温して、そこに５０％の硫酸を６２．５ｍｌ加え、撹拌を３０分間継続し、熟成した。
熟成後、スラリーをヌッチェで減圧濾過した。固形分であるウェットケーキが得られるまでの時間は、１２分であった。ここに洗浄水としてイオン交換水１リットルを注いだ。洗浄水による濾過には１時間を要した。
なお、原子吸光により測定したところ、上記酸洗浄により重金属成分は、３０ｐｐｍから１０ｐｐｍ以下に減少した。
得られたウェットケーキは、例えば実施例２の条件で処理したところ、匹敵する濾過時間および凝集沈降性を示した。
Example 4
This example shows an acid cleaning process to reduce impurities such as heavy metals. A slurry was prepared by dispersing 125 g of titanium oxide (JA-C, manufactured by Taika Co., Ltd.), which had not been subjected to acid cleaning, in 1 liter of ion-exchanged water. The slurry was heated to 80 ° C., 62.5 ml of 50% sulfuric acid was added thereto, and stirring was continued for 30 minutes for aging.
After aging, the slurry was filtered under reduced pressure with Nutsche. The time until a wet cake having a solid content was obtained was 12 minutes. Here, 1 liter of ion exchange water was poured as washing water. Filtration with washing water took 1 hour.
When measured by atomic absorption, the heavy metal component was reduced from 30 ppm to 10 ppm or less by the acid washing.
The obtained wet cake was treated under the conditions of Example 2, for example, and showed comparable filtration time and coagulation sedimentation.
Claims (10)
ｂ）該スラリーのｐＨを中性領域に調節し、熟成する工程、
ｃ）熟成したスラリーを濾過し、ウェットケーキを水洗する工程、および
ｄ）洗浄したウェットケーキを乾燥した後粉砕する工程、
よりなる酸化チタン粉体の製造方法。 a) adding at least 0.03% by weight calcium ion source as calcium to titanium oxide to an aqueous titanium oxide slurry undergoing treatment to reduce heavy metals or water solubles;
b) adjusting the pH of the slurry to a neutral range and aging,
c) filtering the aged slurry and washing the wet cake with water; and d) drying and grinding the washed wet cake.
A method for producing a titanium oxide powder.
The method according to claim 8 or 9, further comprising a step of heating the slurry to 60 ° C or higher before pH adjustment.
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Citations (7)
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|---|---|---|---|---|
| JPS6223988B2 (en) * | 1981-12-03 | 1987-05-26 | Onahama Sakai Kagaku Kk | |
| WO1997024289A1 (en) * | 1995-12-27 | 1997-07-10 | Tohkem Products Corporation | Titanium dioxide reduced in volatile water content, process for producing the same, and masterbatch containing the same |
| WO1997024392A1 (en) * | 1995-12-27 | 1997-07-10 | Toyo Ink Manufacturing Co., Ltd. | Masterbatch containing titanium oxide |
| JPH10194738A (en) * | 1997-01-10 | 1998-07-28 | Nichias Corp | Production of calcium titanate fine particle |
| WO2002053285A1 (en) * | 2000-12-28 | 2002-07-11 | Showa Denko K.K. | Powder exhibiting optical function and use thereof |
| JP2004169246A (en) * | 2002-11-22 | 2004-06-17 | Maruyama Seni Sangyo Kk | Titanium oxide-adhering sheet and method for producing the same |
| JP2004243307A (en) * | 2002-06-27 | 2004-09-02 | Showa Denko Kk | High activity photocatalyst particle, manufacturing method therefor and usage thereof |
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- 2005-08-26 JP JP2005246486A patent/JP2007055875A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6223988B2 (en) * | 1981-12-03 | 1987-05-26 | Onahama Sakai Kagaku Kk | |
| WO1997024289A1 (en) * | 1995-12-27 | 1997-07-10 | Tohkem Products Corporation | Titanium dioxide reduced in volatile water content, process for producing the same, and masterbatch containing the same |
| WO1997024392A1 (en) * | 1995-12-27 | 1997-07-10 | Toyo Ink Manufacturing Co., Ltd. | Masterbatch containing titanium oxide |
| JPH10194738A (en) * | 1997-01-10 | 1998-07-28 | Nichias Corp | Production of calcium titanate fine particle |
| WO2002053285A1 (en) * | 2000-12-28 | 2002-07-11 | Showa Denko K.K. | Powder exhibiting optical function and use thereof |
| JP2004243307A (en) * | 2002-06-27 | 2004-09-02 | Showa Denko Kk | High activity photocatalyst particle, manufacturing method therefor and usage thereof |
| JP2004169246A (en) * | 2002-11-22 | 2004-06-17 | Maruyama Seni Sangyo Kk | Titanium oxide-adhering sheet and method for producing the same |
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