5種類の水酸アパタイト (Ca₁₀ (PO₄) ₆ (OH) ₂;HAp) -ジルコニア (ZrO₂) 系複合粉体をダブルノズル噴霧熱分解法によって調製した。すなわち, (a) 0.50mol・dm^-3Ca (NO₃) ₂および0.30mol・dm^-3 (NH₄) ₂HPO₄がCa/P比1.67になるように調製した硝酸酸性溶液と, (b) 1.2125～9.7000×10^-2mol・dm^-3ZrOCl₂および0.75～6.00×10^-4mol・dm^-3 YCl₃がY₂O₃/ (ZrO₂+Y₂O₃) 比0.03になるように調製した溶液とを2個のノズルを用いて同時に噴霧熱分解して目的の化合物を調製した。えられた粉体の (ZrO₂+Y₂O₃) 含有量は9.71mol%から79.42mol%の範囲にあった。これらの複合粉体の成形体を1100℃, 1時間ホットプレスしたところ, (ZrO₂+Y₂O₃) 含有量が9.71mol%の場合に相対密度が99.0%の高密度焼結体をえることができた。この焼結体の結晶相はHAp, 正方晶ZrO₂およびβ-Ca₃ (PO₄) ₂ (少量) であった。また, HAp/β-Ca₃ (PO₄) ₂の結晶粒界および結晶粒内には約0.1μmのZrO₂結晶粒が均質に分散していた。

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Antimicrobial activities of ceramics of Ag-containing zeolite, MgO and CaO were determined by a conduction-type batch calorimeter capable of measuring heat evolved in multiplicative growth of soil microbes. The peak of heat evolution due to microbial growth with metabolic degradation of glucose in soil shifted toward a longer incubation and the ascending slope of heat evolution became less steep as the ceramic concentration in soil increased. The growth rate of soil microbes was examined using the non-competitive inhibition kinetic model proposed by Takahashi et al. Drug potency (antimicrobial efficacy) curves of the ceramics were drawn with using kinetic parameters obtained. The calorimetric method was found to be useful for quantitatively evaluating the efficacy of antimicrobial ceramics.

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消石灰, セッコウおよび水酸化アルミニウムの混合物を出発原料として, 遊星ミルを用いて乾式粉砕し, 常温でのカルシウムサルフォアルミネート (CSA) 水和物のメカノケミカル合成を試みた。1時間粉砕後の産物には, 異なる種類のCSA水和物が混在し, メカノケミカル合成が達成できる。えられたCSA水和物は, か焼温度約773Kでほぼ無水物となる。この無水化温度は, 市販のCSA粉体の製造温度と比較して極端に低い。メカノケミカル合成によってえられたCSA水和物は, 水添加によって硬化し, エトリンガイトを形成する。原料の粉砕後, か焼した試料に水を添加し, 10日間放置した硬化体の硬度は, 原料に対する粉砕時間が長いほど大となる。一方, か焼なしの場合は, 1時間粉砕の試料で硬度が極大値を示す。さらに, これらの硬化体硬度は, 市販のCSA粉体から調製した硬化体硬度よりも大となる。

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Among methods of handling waste which contains toxic heavy metals, fixation in concrete has gained broad acceptance and is commonly used. If waste containing highly toxic hexavalent chromium is to be fixed using normal portland-type cement, the possibility of secondary contamination should be eliminated by preventing any elution of hexavalent chromium from the hardened paste over a long period of time. Thus it appears that simply using concrete is inadequate.
We turned their attention to a chemical reaction that occurs when hexavalent chromium reacts with barium ions in an alkalescent domain. The reaction generates barium chromate, which is insoluble. Thus barium chloride was added to high-early-strength portland cement and the material was used to fix hexavalent chromium. This paper reports on that process because it was proved that the material can fix waste which contains hexavalent chromium for a long time.
Using X-ray diffraction and SEM (scanning electron microscopy), it was confirmed that the fixing mechanism is a consequence of the generation of insoluble barium chromate.
Today many fields are creating demand for the stable fixation of waste which contains hexavalent chromium. We believe that treatment using the fixation material described here is highly effective.

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Fire resistant stone (FRS) in Niijima island of Tokyo consists mainly of glassy aluminosilicate. A high quality soda-lime glass (FRS glass) have already prepared with FRS as main raw. material.
The purpose of this work is to study developping β-wollastonite glass-ceramic from the crashed FRS which passed through a screen of 32 mesh.
The batch composed in the weight ratio of 100 FRS, 50-60 limestone, 0-10 soda ash, 4 sodium sulfate, 1 graphite and 2 zinc oxide, respectively. the batch melted easily in a covered crucible at 1450°C and the black glass was obtainable. the glass was reheated at 1050°C and non-colored β-wollastonite glass-ceramic was obtainable. If zinc oxide was not added, black glass-ceramic was obtainable. The properties of the fl-wollastonite glass-ceramic prepared were as follows : thermal expansion coefficient 78 × 10^-7/°C, Shore hardness 117, bending strength 850 kg/cm², acid resistance 2 mg/cm² (10H₂SO₄, 90°C, the weight loss after 24h) and these were excellent for building material.

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