侯氏制碱法 Hou's process — 定义、原理与由来

定义Definition

侯氏制碱法是中国化学家侯德榜把氨碱法与合成氨联合起来的制碱工艺：析出 NaHCO₃ 后的母液不再加石灰回收氨，而是通氨、加食盐并冷却，析出氯化铵作为氮肥，母液循环回碳酸化工序。同时得到纯碱和氯化铵两种产品。

Hou's process, devised by the Chinese chemist Hou Debang, couples the ammonia–soda process with ammonia synthesis. After NaHCO₃ is removed, the mother liquor is not treated with lime; instead ammonia and salt are added and the liquor is cooled so that ammonium chloride crystallises as a nitrogen fertiliser, and the liquor returns to carbonation. Soda ash and ammonium chloride are co-produced.

原理Principle

利用 NH₄Cl 的溶解度随温度降低明显减小、而 NaCl 变化很小的特点：低温（约 0–10 °C）下加入食盐细粉产生同离子效应，使 NH₄Cl 析出。合成氨厂同时提供 NH₃ 和 CO₂（变换气），所以不需要石灰石煅烧。

NH₄Cl solubility falls steeply on cooling while NaCl's barely changes; at about 0–10 °C added fine salt (common-ion effect) salts out NH₄Cl. An ammonia plant supplies both NH₃ and CO₂ (from shift gas), so no limestone burning is needed.

由来Origin

侯德榜（1890–1974）曾主持永利碱厂打破索尔维法的技术封锁，并于 1933 年出版英文专著《纯碱制造》。抗战期间在四川研究改进，1941 年提出联合制碱工艺，被命名为“侯氏碱法”；1960 年代在大连建厂实现工业化。

Hou Debang (1890–1974) led the Yongli soda works in breaking the Solvay technology monopoly and published Manufacture of Soda in English in 1933. During the war he developed the combined process in Sichuan, announced in 1941 and named Hou's process; it was industrialised at Dalian in the 1960s.

优点Advantages

食盐利用率提高到 95% 以上，不产生 CaCl₂ 废液，省去石灰窑和蒸氨塔，联产化肥，经济和环保效益显著。

Salt utilisation rises above 95 %, no CaCl₂ waste is produced, the lime kiln and ammonia still are eliminated, and fertiliser is co-produced.

反应Reactions

NaCl + NH₃ + CO₂ + H₂O ⟶ NaHCO₃↓ + NH₄Cl2 NaHCO₃ ⟶ Na₂CO₃ + CO₂ + H₂O母液冷析 NH₄ClNaCl + NH₃ + CO₂ + H₂O ⟶ NaHCO₃↓ + NH₄Cl; 2 NaHCO₃ ⟶ Na₂CO₃ + CO₂ + H₂O; NH₄Cl

碳酸化约 30–40 °C；冷析、盐析约 0–10 °C

Carbonation at about 30–40 °C; cooling and salting-out at about 0–10 °C

氨盐水碳酸化析出 NaHCO₃，煅烧得纯碱。
Carbonate ammoniated brine to precipitate NaHCO₃ and calcine it.
母液吸氨、冷却、加食盐，析出 NH₄Cl。
Ammoniate, cool and salt the mother liquor to crystallise NH₄Cl.
析铵后的母液补充食盐，返回碳酸化循环。
Return the liquor, topped up with salt, to carbonation.

NH₄Cl溶液冷却 + NaCl⟶ NH₄Cl↓NH₄Cl(Solution (chemistry)) cool + NaCl⟶ NH₄Cl↓

同离子效应与温度共同作用。

Common-ion effect plus cooling.

年表Timeline

1926
永利碱厂“红三角”纯碱获万国博览会金奖
Yongli's ‘Red Triangle’ soda ash wins a gold medal at the Philadelphia exposition
1933
侯德榜出版《纯碱制造》
Hou publishes Manufacture of Soda
1941
提出联合制碱法，命名侯氏碱法
The combined process is announced as Hou's process
1964
联合制碱法通过国家鉴定并推广
The process passes national evaluation and spreads

侯氏制碱法Hou's process