The synthesis of α-gypsum hemihydrate and control of its morphology were investigated by adding H₂SO₄ solution into saturated solution of II-anhydrite which was dissolved in HNO₃ solution under atmospheric pressure at 100°C. Characteristics of the hemihydrate were determined by means of X-ray diffraction, thermal analysis (TG-DTA), scanning electron microscopy and chemical analysis.
II-anhydrite was easily dissolved into HNO₃ solution at 100°C, and its maximum solubility was 3.2g/100 cm³ in 2.9mol·dm^-3 HNO₃ solution. α-hemihydrate was synthesized by adding H₂SO₄ solution into the CaSO₄-HNO₃ system saturated solution. Supersaturation degree of II-anhydrite remarkably affected to morphology and stability of α-hemihydrate. The degree was controlled in the range of 0.6 to 1.8 by changing concentration of H₂SO₄ solution. At supersaturation degree of 0.7, α-hemihydrate with aspect ratio 26 (650μm×∅25μm) was formed after 30 min, but it was dehydrated slowly to II-gypsum anhydride after more than 90 min. The many kinds of sodium carboxylates, MgCl₂ and NH₄NO₃ were added in synthetic process to produce large blocky crystal (small aspect ratio). The aspect ratio was decreased by increasing number of carbon in alkyl group constituting additives and amount of additives. The inorganic additives were effective to the growth in the length direction of α-hemihydrate particle against that of organic additives.
The synthetic technique of α-hemihydrate from II-anhydrite under atmospheric pressure was proposed in the present paper as a recyclable process of HNO₃ and H₂SO₄ solutions.

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Fire resistant stone (FRS) in Niizima island of Tokyo consists mainly of glassy aluminosilicate.
The purpose of this work is to study developing a new use for FRS. A high quality soda-lime glass (FRS glass) was prepared from the crashed FRS which passed through a screen of 32 mesh. The batch composed of 100 parts of FRS, 25 parts of limestone and 30 parts of soda ash by weight, melted easily in a crucible at 1450°C. Neither stone nor cord appeared in the glass. Furthermore, when only 0.2 wt% antimony oxide with oxidizing agent was added in the batch, the glass became almost seed-free. Melting rate of the batch with FRS became 30% higher than batch with general raw meterial. FRS glass was slightly short glass, but could be formed in the same manner as soda-lime glass in the market. Hydrolytic resistance of FRS glass was particularly superior to that of soda-lime glass in the market. Amber glass and heat-absobving glass could be produced at a low cost with FRS as a main raw material.

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Simultaneous adsorption of NH₄⁺ and PO₄^3-ions on the mixed adsorbents of zeolite/allophane, zeolite/aluminum sludge, and zeolite/lime was studied. As a result, it was found that the adsorbents of zeolite/allophane and zeolite/aluminum sludge absorbed relatively large amount of NH₄⁺ and PO₄^3- ions. Also, the absorption data of NH₄⁺ and PO₄^3- ions on zeolite/allophane and zeolite/aluminum sludge carried out by using Akiyama river water and sewage disposal water indicated that they were effective adsorbents for two ions.

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The procedure of A type zeolite synthesis from fly ash was studied. A small amount of hydroxysodalite was formed from fly ash by hydrothermal reaction with 2N or 6N NaOH solution at 90°C. In the case of adding sodium aluminate content to above reaction mixture, the yield of hydroxysodalite increased but A type zeolite was not formed at all. A powder of reactive sodium silicate compound was obtained by heating the fly ash and solid sodium hydroxide at 90-130°C for 2-20 hours. A type zeolite was easily synthesized by hydrothermal reaction of the pretreated fly ash and an admixture of sodium hydroxide, sodium aluminate, water and seed of A type zeolite at 90°C for 2 hours. The yield of A type zeolite increased lineally with the reaction ratio between the fly ash and solid sodium hydroxide. The yield of A type zeolite was about 65% at the optimum condition. CEC of A type zeolite from the fly ash was about 300 meq/ 100 g.

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Pulverized coal samples with two kinds of particle size were fed into a vertical laminar flow furnace and burnt in the oxygen gas in the temperature range from 1073 to 1223 K. For the large particles, linear relationships between unburnt carbon ratio and residence time in the furnace were observed and the combustion process was divided into two regions of rapid and slow rates. At the early stage of the combustion where fragmentation of large particles was observed the char and volatile matter combustion occurred simultaneously, and the volatile matter remained even at the late stage. High oxygen concentration on the particle surface measured by XPS confirmed the char combustion at the early stage. Carbon spectrum indicated the existence of three kinds of oxygen combined with carbon on the surface. Of the three, the C-O type bond was closely related to the char combustion and the desorption of CO from the surface was considered to be rate-determinant.
1. The combustion rate of large particles was higher than that of small ones, and the combustion of large particles proceeded with two steps; the fast combustion at the early stage and the gradual one at the late stage.
2. The char combustion by oxygen diffused to the particle surface occurs from the beginning of combustion in both cases of large andsmall particles, but the explosion of large partides caused by the violent release of volatile matter enhanced the combustion rate of the large particles.
3. In the case of small particles, the volatile matter was released gradually and char burns slowly during the combustion.
4. The oxygen which causes cahr combustion was chemisorbed on the cahr surface forming the C-O bond and the desorption of CO from the surface determines the combustion rate.

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A flow-injection analysis (FIA) system is presented for the determination of phosphorus in cement, which is based on the formation and spectrophotometric detection of molybdenum blue under coexistence of potassium antimonyl tartrate in a FIA system, the sample was dissolved in perchloric and hydrochloric acids solution, and then silica was removed by filtration. The dissolved solution was diluted twice and injected to FIA system. The sample solution injected into the carrier stream (0.18 M perchloric acid and 0.06 M hydrochloric acid) is mixed with a reagent stream (0.8 M sulfic acid, 4 mM ammonium molybdate, 0.3 mM antimonyl potassium tartrate and 0.3% ascorbic acid) at a confluence point. Then the molybdenum blue was developed in the reaction coil which was immersed in a temperature controlled bath (65°C) and the absorbance was measured at 880 nm. The recommended concentration range of phosphorus was 0.2-3.0, μg/ml and the limit of detection was 0.05, μg/ml of phosphorus. It has proved that the FIA system allows simple and rapid analysis without complicated manual operations; only 2 min is required for analytical measurement after sample injection.

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Thermal decomposition of crystalline pentahydrous copper (II) sulfate was studied by thermogravimetric analysis and differential thermal analysis.
It is concluded that crystalline pentahydrous copper (II) sulfate undergoes a three-step decomposition to become anhydrous copper (II) sulfate.

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