The difference between ammonia alkali and double alkali

From the perspective of manufacturing processes, soda ash can be produced through three methods: the natural soda method, the ammonia-soda method, and the combined soda method; the latter two are chemical synthesis methods. The production capacity ratio of the ammonia-alkali method, the combined-alkali method, and the natural-alkali method in China is approximately: 58% : 38% : 4%. The main difference between the ammonia-alkali process and the double-alkali process is as follows: (1) The main product of the ammonia-alkali process is soda ash, but it may also generate a large amount of waste containing various ions. How to make comprehensive use of this waste in order to reduce its negative impact on the environment is a serious challenge for companies that use the ammonia-alkali process ； The main products of the double-alkali process are soda ash and ammonium chloride (1 ton of soda ash is produced along with 1 ton of ammonium chloride), resulting in less waste; thus, it is more environmentally friendly than the ammonia-alkali process. (2) The substances recycled in the two methods are different, hence the efficiency of raw material utilization varies. 　　In the ammonia-alkali process, synthetic ammonia is reused, resulting in a high utilization efficiency; however, the utilization efficiency of the raw salt is lower (around 70%). Therefore, such plants are usually built in areas where there is an ample supply of raw salt ； In the combined alkali process, the utilization efficiency of the raw salt is high (over 98%), while that of synthetic ammonia is lower; therefore, combined alkali plants are usually built in areas where there is an ample supply of synthetic ammonia, and they are often constructed alongside synthetic ammonia production facilities. (3) In terms of capacity distribution, the plants using the combined alkali process are generally of smaller scale. However, by combining soda ash production with ammonia production, the need for equipment for burning limestone to produce CO2 and for ammonia vaporization is eliminated, which **reduces investment costs and improves economic efficiency**.

Reply to 2# syltshen: Thank you; I’ve learned something new, but it doesn’t seem to be mentioned regarding dehydration equipment. I hope someone who knows can share it

What is a dehydration device? Do you mean a centrifuge? What you’re saying is a bit too general.