We measured the contact-angle between water and Shijo-surface, and found that the contact-angle increased with the concentration of NaCl solution, while it showed no connection with the state of Shijo-surface. Furthermore, we investigated using a model “Shijoka”, the phenomenon of adhesion of flowing water on the “Shijo”. In these tests it was found that the surface ratio of adhesion water was the greatest in the third or fourth layer of bamboo branches, when the angle of branches was set at forty degrees.

抄録全体を表示

In order to study some effects of chlorides on the physical properties of soil, we tested the consistency, the compacting density and the compressive strength of weathering granite soil. Sodium chloride, calcium chloride and magnesium chloride, ranging from 0 to 5% of chloride content, defined as a percentage of dry weight of soil, was in turn added to the soil.
Results obtained are summarized as follows.
(1) Both the liquid limit and the compacting density increase with increasing chloride content.
(2) The compressive strength in the uniaxial compression test shows clearly fall-off with-increasing chloride content within range of water content from 5 to 10%.

抄録全体を表示

Recently, studies were made on magnesium hydroxide which contains boric acid, as a raw material for magnesia clinker.
This investigation was performed following its production through absorption of boric acid to magnesium hydroxide previously studied by the same authors.
The magnesium hydroxide was precipitated from magnesium chloride solution with sodium hydroxide or calcium hydroxide, and mixed with the boric acid solution after sufficient washing.
The experimental results were as follows:
(1) The amounts and rate of absorption were remarkably effected by the conditions of magnesium hydroxide. The magnesium hydroxide which was freshly precipitated and kept in wet condition absorbed strongly, while that which was exposed to air absorbed weakly.
(2) The relation between the amount of absorbed boric acid and the concentration of boric acid solution showed agreement with Freundlich's absorption isotherm. From these results, a convenient diagram was made for producing magnesium hydroxide containing the requested amounts of boric acid, and magnesium hydroxides containing 0.5-5% of boric acid were made by use of this diagram.

抄録全体を表示

1. Boron compound contained in sea water, move to its concentrated products, brine or bittern, containing about 90% of its total quantities.
2. Using various solvents, extraction of B-compound from bittern acidified by HCl and amyl alcohol or buthyl alcohol gave the best result, while results with other agents, such as ether, carbon tetra chloride, chloroform etc., were lower.
3. The extracted B-compound were easily removed to alkalic solution.

抄録全体を表示

The behavior of fluorine in the processes of salt making was studied through the analysis of fluorine in the following samples.
(1) Samples of scales deposited at the lower and at the higher concentration degrees, common salt, and the final mother liquor, prepared by the concentration of sea water in vitro under six different conditions.
(2) Samples of sea water, brine, common salt, mother liquor, bittern, and scales, collected from four salt making plants of different processes.
The results obtained were as follows:
1. In the case of concentration of sea water in vitro:(1) There was no large difference in the behavior of fluorine among different concentration conditions.(2) The distribution percentages of fluorine (the percentage of the amount of fluorine in the deposits or mother liquor to the total amount of fluorine in the sea water used.) were 53 to 63% in the scale, 0 to 5% in the common salt, and 36 to 47% in the final mother liquor.
2. In the case of plant processes:(1) The difference of salt making process had little effect on the behavior of fluorine.(2) The distribution percentages of fluorine were about 90% in the scale, 0 to 5% in the common salt, and 3 to 6% in the bittern.
3. It was presumed that fluorine dissolved in sea water and brine might be in the form of calcium fluoride, and that, when the deposition of scales took place, dissolved calcium fluoride might be adsorbed on the scales and coprecipitated with them.

抄録全体を表示

It was found that new double salts having the general chemical formula (K, NH₄) ₂SO₄·2MgSO₄ were formed, by the addition of (NH₄) ₂SO₄ to bittern at about 100°C.
Thermogravimetric analyses, X-ray diffraction patterns and indices of refraction of these salts were studied in comparison with those of Langbeinite and (NH₄) ₂SO₄ 2MgSO₄.
The results were as follows:
1) The more NH₄ the double salts contained; the more unstable nature, the higher peaks at 15.4° and 21.9°(2θ) and the larger indices of refraction they had.
2) Their crystal structures seemed to be analogous to that of Langbeinite.

抄録全体を表示

The informations on pneumatic conveying dryer with horizontal or inclined type drying column were described in previous papers. In this study, drying test of salt was done using a dryer with vertical type drying column. It was found that this type excells in comparison with the other types on the point of efficiency and prevention of cohesion of impurities onto the wall of drying column.
Moreover, from the results of velocity test in the vertical type, size reduction of crystals was not observed at air velocities of 22m/sec or less.
The operating conditions to obtain products with water content of 0.1%, were as follows; air velocity 22m/sec, inlet air temperature 150°C, feed ratio of material wt. to air wt.1.0 or less. 5m was found long enough for the length of drying column, and power consumption was about 45KWH per 1 ton of salt.

抄録全体を表示

フエロシアンイオン添加による食塩の固結防止機構は次のように考えられる.
1 食塩の結晶表面に附着している水分の乾燥状態ではこの水分中のフエロシアンイオン濃度が0.02%程度以上であれば媒晶作用のため1つの粒子が数μ以下のゆるくつき合つた正8面体の微結晶を食塩粒子のまわりに析出して, 食塩粒子間に橋渡し現象 (bridging或いはcementing) がおこらず, 従つて固結現象をおこさない.
2 吸湿状態にあつてはフエロシアンイオンの作用により食塩の溶解速度と溶解度が小さくなるためフエロシアンイオンの存在しない食塩に比べて食塩結晶表面に附着する食塩水濃度が低くなり, 従つて吸湿速度が小さくなる.
3 吸湿, 乾燥の繰り返しがおこつてもフエロシアンイオンが存在する限り食塩粒子間にbridgiagをおこさず, かえつて表面における微結晶の分散がおこなわれ非固結性を増す.

抄録全体を表示

(1) 750μの平均粒径を有する球状の粗粒子塩を用いて理想状態における食塩塊の微小部分と見なし得る成型サムプルを調製し, 恒温恒湿槽により吸湿, 乾燥試験を行なつた.
(2) 吸湿の場合には水分m (乾量基準), 時間θと固結強さyとの間には次の関係が成立する.
m=Aθ+m_o=A(θ+θ_o)=Aθ,(θ=θ+θ_o)
y=y_oθ^-1/4=A^1/4y_om^-1/4=L₁m^-1/4
(3) 乾燥の場合には次の関係が成立する.
m=m_oe^-Bθ
y=y_oe^Cθ=m_o^4/3y_om^-4/3=L₂m^-4/3
(4) 履歴現象は次のように表わされるものと考えられる.
y=ΣA^1/4y_om^-1/4+Σm_o^4/3y_om^-4/3=ΣL₁m^-1/4+ΣL₂m^-4/3
(5) 現実の固結現象における固結強さYは前報の定常条件における固結強さをy₁, 本報の水分変化における固結強さをy₂とすれば次のように表わしてよいものと思われる.
Y=y₁+y₂
(6) yはmの函数であつて, 吸放湿量の函数ではない. また, m以外のすべての因子は吸放湿速度には影響するがyとは直接の関係がない.
(7) 水分変化における食塩の固結機構は溶解, 再結晶にともなう架橋の消長であることは明らかであり, 本試験結果から種々の考察がなされるが何れも推定の範囲を出ないので省略する. 本試験結果は現場や他品種へ広く適用できるものと考えられるが, これ等については別途に試験を行なう予定である.

抄録全体を表示