Relationships between characteristics and hydraulic reactivity of fused calcium aluminate and crystalline calcium aluminate, hydration characteristics of accelerating agent based on calcium aluminate were investigated to obtain the fundamental data concerning the hydration characteristics in the initial stage of quick setting process.
(1) The structure of the Al₂O₃ group in fused calcium aluthinate resembled the γ Al₂O₃ type while that of the crystalline calcium aluminate a Al₂O₃ type. The heat of diffolution of the fused calcium aluminate is greater than that of the crystalline one by over 50 cal/g.
(2) The heat evolution rate in hydration of the fused calcium aluminate immediately after the addition of water is greater than that of crystalline calcium aluminate by 2 or 3 times. The hydration during the initial period of fused calcium aluminate increases as fineness increases. This ten-dency is greater than that of the crystalline calcium aluminate.
(3) When appropriate amounts of Na₂Al₂O₄, Al (OH) ₃, Ca (OH) ₂, Na₂CO₃ and CaSO₄ are added to the calcium aluminate and mixed to the cement paste, quick setting is obtained; quick setting occurs in 30 seconds after the addition of water when only 7% of accelerating agent is added. The acceleration effect is freater when fused calcium aluminate is used compared with the case of crystalline calcium aluminate.
(4) The amount of heat evolution in hydration of the crystalline calcium aluminate immediately after the addition of water is less than that of fused calcium aluminate. However, since the lime saturation ratio in liquid phase is maintained in high level, vivid hydration of alite is promoted. (5) The hydrates produced in cement paste containing of accelerating agent immediately after the addition of water are calcium aluminate hydrate, monsulfate hydrate and ettringite. Especially amount of ettringite is remarkably different between accelerating agents based on fused calcium aluminate and crystalline calcium aluminate.

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Fibrous carbonate-containing hydroxyapatite (CO₃HAp) which had long axes of about 50 pm was prepared by homogeneous precipitation method, using urea. The fibrous CO₃HAp materials were compressed at a pressure between 50 and 200 MPa to form compacts. The compacts were fired at a temperature between 1100 and 1350°C for 5 h to form the porous hydroxyapatite ceramics. The results obtained are summarized as follows :
(1) Acidic-aqueous solutions (0.1 mol. dm^-3 HNO₃ 1500 cm³) containing 0.167 mol·dm^-3 Ca (NO₃) ₂, 0.1 mol·dm^-3 (NH₃) ₂HPO₄ (Ca/P =1.67) and 0.5 mol·dm^-3 (NH₂) ₂CO were heated under two conditions : (i) 80°C for 24 h and then 90°C for 72 h or (ii) 80°C for 24 h and then 95°C for 46 h. The fibrous CO₃ HAp with Ca/P =1.66 was prepared under both conditions.
(2) Porous hydroxyapatite ceramics which had the porosities of 43% to 10% were easily fabricated from firing the above compacts. The compressed strength of the ceramics with the porosity of 20% showed an average value of 45 MPa in 10 test pieces, ranging from 30 to 60 MPa.
(3) The pore-diameter distribution of ceramics with the total porosity of 39% showed a narrow normal-distribution histogram, ranging from 1 pm to 0.1 pm.

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The heats of ion exchange for alkaline metal ions and those of intercalation for n-alkylamines into a-zirconium phosphate (α-ZrP) have been measured in aqueous solution and ethanol solvent by a twin conduction type microcalorimeter. It was found that the ion exchange for alkaline metal ions and intercalation of n-alkylamines in α-ZrP were exothermic reaction assisted with neutralization effect as driving force. The heats of them decreased with increasing in initial concentrations of the guest alkaline ions and n-alkylamines. Taking the results from the XRD before and after the ion-exchange reaction of α-ZrP into account, hydrated Li⁺ ions in aqueous solution were considered to be exchanged for protons (H⁺) in interlayer of α-ZrP with almost perfectly dehydrated states, while Na⁺ ions were exchanged in partially hydrated state. These phenomena were explained to be due to the estimated larger positive entropy changes (ΔS) by the dehydration effect for the Li⁺ ion exchange than those of the Na⁺ ion exchange reaction.
The order of the exothermal intercalation heats of n-alkylamines in aqueous solution was C³> C⁴> C⁶ > C⁸, while that in ethanol solution was C⁸ > C⁶ > C⁴> C³. The reverse result was estimated to be due to the difference of basicity strength of the amines by induction minus effect (-I effect) of the alkyl groups in aqueous and ethanol solution.

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Disodium dihydrogentetra-μ-imido-cyclo-tetraphosphate dihydrate has been made by adjusting pH of a solution of tetrasodium tetra-μ-imido-cyclo-tetraphosphate at 2.0 with hydrochloric acid. The compound was stable below 125°C and produced many kinds of imidopolyphosphates above 125°C.
Anhydrous diammonium dihydrogentetra-μ-imido-cyclo-tetraphosphate has been prepared by making the pH value of a solution of tetra-μ-imido-cyclo-tetraphosphoric acid above 10 with aqueous ammonia and then acidifying the solution to a pH value lower than 5.0 with hydrochloric acid. The product was stable up to 180°C. On heating at a higher temnernture it produced many kinds of condensed phosphates with imino groups.

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Ion-exchange of K_1.19H_0.81V₂Mo₃O₁₅·nH₂O with a layered type structure prepared from K₂V₂Mo₃O₁₅ via ion-exchange reaction is attempted with alkaline and alkaline earth ions. Both of potassium and proton in the interlayer space are partially ion-exchanged to yield (K, A, H) ₂V₂Mo₃O₁₅·nH₂O (A; alkaline and alkaline earth metal). The uptake amount of Li⁺ ion is very small and no uptake amount of Mg²⁺ ion is observed, and the uptake amount of other ions increases with their ionic sizes. The basal spacings of hydrated phases for ion-exchanged compounds are independent of ionic size, but those of dehydrated one except the Li and Ca derivatives increase with ionic size.

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The effects of shape change on combustion of pulverized coal particles have been investigated in order study of pulverized coal combustion in high oxygen contest. In this experiments, pulverized coal particles were fed into a vertical laminar flow furnace at 1073 through 1223 K. The combustion mechanisms were studied by the various characteristics of sampled particles at arbitrary position in the furnace.
Experimental relationship between unburnt carbon ratio and residence time has been observed as two staged straight lines, which shows ordinaroly, the volatile matter combustion region followed by the char combustion region. However, the cause of this combustion transition was the change of particle structure. The char combustion occurred simultaneously in the volatile matter combustion region, and the volatile matter remained in almost burnt particles. The combustion of pulverized coal particles were influenced by the shape change of particles such as pore formation and explosion which resulted from rapid coal devolatilization.

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A new fabrication process using a drying-consolidation property of precipitated gelatinous calcium-deficient hydroxyapatite was investigated. A comparatively large crack-free compact of 30 mm in diameter and 4 mm in thickness was obtained.

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