海水から淡水を製造する多段フラツシユ蒸発装置について, 装置の最適化に関する諸項を解析し, 最適条件を試算した.
その結果,
(1) 淡水コストと変動因子 (段数と蒸発率) との関係は (14) 式で示される.
(2) 最適装置の段数および蒸発率は与えられる出力条件およびエネルギー条件に対応して変化する, その関係を一般化すれば (15) 式となる.
(3) 多段フラツシユ型蒸発装置の最適条件は試算条件の具体化 (表-3) によつて (15') 式から求められ, 造水規模を日産1,000～100,000トン, 熱源蒸汽単価を100～1,000円/トン, 所要動力の単価を3円/KWHの範囲とするとき, 最適段数, 最適蒸発率, 最適平均管端温度差および最適熱源蒸汽消費率はそれぞれつぎの関係式で示される.
N_o=0.16・C₂^0.5・E^0.158[-]
τ_o=1920・C₂^-0.5・E^-0.129 [kg/m²h]
γ_mo=375・C₂^-0.5・E^-0.158・{exp (0.88/E^0.029)-1}^-1[℃]
F_o=0.0181+0.0332・γ_mo[kg加熱蒸気/kg淡水]

抄録全体を表示

A study was conducted on the precipitation recovery of strontium from brine. In this study, the precipitation behavior of strontium was traced by using radioactive isotope ⁸⁹Sr, and those of calcium and magnesium by EDTA titration.
The separation of magnesium was carried out by applying the difference in the solubility among calcium, strontium and magnesium bicarbonate contained in the solution saturated with carbon dioxide. By bubbling carbon dioxide into slag containing carbonates, about 80% of magnesium was dissolved. After removing the most part of magnesium by carbon dioxide, strontium was separated by adding sodium hydroxide at temperature 80°C. By this procedure, more than 70% of calcium was precipitated as hydroxide, and the precipitation of residual magnesium was complete.
Strontium was then separated as sulfate by adding ammonium sulfate.
The over-all chemical recovery of strontium amounted to 55-60% after the abovementioned separation process.

抄録全体を表示

For the improvement of quality of common salt and the protection of corrosion of salt making equipments, various methods have been studied by several groups of workers in recent years. The present investigation of the behaviors of iron on salt making process was undertaken in order to make a choice of the emphasis point and estimation of the effects to application of these methods, and to develop the methods for improving the quality of common salt. The examination was chiefly carried out in two factories of a common type in the Setonaikai district, Japan. The resuts were as follows:
1) The existence form of iron in salt making process was chiefly solid, and soluble iron was usually little except in bittern: Therefore, it is possible to remove most of these irons by filtration.
2) Inorganic iron. was accompanied by calcium sulfate, and therefore iron was decreased in the process of removing suspended calcium sulfate.
3) Iron in brine was regulated by the concentration operation by addition of crystal seed of calcium sulfate. But it was suggested that this operation was effective to the corrosion protection because of degassification of dissolved oxygen.
4) The material balance of iron in salt making process was obtained, the Contamintion of iron was, chiefly occured at evaporator, preheator and brine, and this iron was displaced chiefly to bittern and its slurry.
5) The salt washer using mother liquor was effective to the uniformity of iron content and the removal of iron in salt up to about 1 ppm. But tri-iron tetroxide (blackish granulated impurity) was not removed sufficiently.
6) The corrosion product on the wall of evaporating part of evaporator was chiefly detected as tri-iron teroxide and partially detected iron as carbide and iron oxychloride. The corrosion product on the wall of liquid part of evaporator was presumed as ferric hydroxide. Blackish granulated impurity in common salt was considered originate in the wall of evaporator, and reddish colloidal impurity was probably originated in the wall of liquid part of evaporator, preheator, and other contacted parts with liquid.
7) The Corrosion rate of evaporator calculated from these results was that mild steel was 0.26 mm/y, mild steel coated with wood was 0.09 mm/y, and cast iron was 0.06 mm/y. Corrosion cathodic protection with zinc was effective in any evaporator.

抄録全体を表示

砕石, 砂, 粘質土よりなる配合土にセメントを3～10%, 塩を0.2～3%添加したものについて突き固め試験, 一軸圧縮強度および安定度試験を行なつた.
その結果,
(1) 塩を添加すると最適含水比は減少し, 最大乾燥密度は増加する.
(2) 塩を添加すると無添加のものにくらべ乾燥密度と圧縮強度はともに増加するが, あまし塩量を増しても良くない. 添加塩量が1%のとき最高値を示した.
(3) 添加塩量と強度の関係は, いいかえると添加塩量と使用セメント量の関係である. 添加塩量は1%で最高値を示すが, 塩量が半減しても強度低下はわずかである. したがつて使用セメント量を節減するという経済的な見地から見れば添加塩量は0.5%が適当と思われる.
(4) 防府市の航空自衛隊でソイルセメント舗装を行なつた結果では, 設計強度30kg/cm²を得るに要するセメント量は7%, これを塩添加法で行なうと所要強度を得るに必要なセメント量は4.5%で, したがつて材料費は約20%節減できた.
(5) 安定度試験の結果はいずれも良好で塩添加法が充分使用しうることがわかつた. また膨張, 収縮率や乾燥一吸水による重量変化率が小さくきわめて安定であるといえよう.

抄録全体を表示