How to extract sodium bicarbonate from wastewater containing about 3% sodium bicarbonate

If it costs 100 yuan to evaporate one ton of water, can the profit from selling 30 kg of sodium bicarbonate cover that cost?

Heating and evaporating sodium bicarbonate causes it to decompose into sodium carbonate. Currently, the market price of sodium bicarbonate is 1,500 per ton, which is not cost-effective. The solution can be used as a neutralizing agent to neutralize acidic wastewater.

This post was last edited by arpcd on 2019-10-12 at 12:02. If you consider it valuable, your company can conduct a detailed cost analysis. Taking the five-effect evaporation process, which is commonly used for evaporation concentration, as an example: for a solution with a concentration of 3%, 33.33 tons of water need to be evaporated to produce 1 ton of pure soda ash. The amount of steam required is 0.27 tons of steam per ton of water (this represents the basic energy consumption for five-effect evaporation). Thus, the steam consumption is 9 tons per ton of soda ash, and when converted to pure sodium carbonate, this amounts to 14.26 tons per ton of pure soda ash. . A preliminary cost calculation can be done: if steam costs 100 yuan per ton, according to Xiao Su’s estimate the cost is 900 yuan per ton; whereas using soda ash, the cost is 1426 yuan per ton. . . . . Add the costs of salaries for other staff and equipment depreciation, and compare them with market prices: soda ash costs around 1500 yuan per ton, while sodium carbonate costs 2200 yuan per ton. As long as management is proper, there should be no losses; there shouldn’t be any major issues in running this small workshop. . . . I’m not sure what the scale of wastewater treatment is for the person who posted this. For bulk chemical raw materials like baking soda and soda ash, it’s necessary to have a sufficient scale of production in order to achieve profitability; if the scale is too small, losses will definitely occur. For example, if you can only produce half a ton of baking soda per hour, you’ll surely lose money, but if you can produce 10 tons, you’ll definitely make a profit. . . Of course, as the baking soda solution is gradually concentrated, some of it decomposes into soda ash, and some CO2 escapes; it is recommended to use soda ash instead, as that is a simpler and more straightforward approach. . . The cheapest option is————if your company has large areas for drying, there’s no need to use steam; you can rely on natural conditions instead: lol

I need to concentrate it to over 10% before subjecting it to evaporation

Are there any methods available to concentrate it to over 10% now?

It should be carried out from an environmental protection perspective; depending on one’s economic conditions, a three-effect concentration unit should be installed, followed by concentration and crystallization, and then centrifugal drying. The resulting concentrated liquid is integrated into the existing system. Mainly by making comprehensive use of the waste heat steam from our company, wastewater is prevented from being discharged, thus meeting environmental protection requirements. By taking into account factors such as the site, funding, the company’s technical capabilities, and securing environmental protection funds, economic benefits can be achieved.

It may be necessary to consider not only the costs of recycling but also the costs associated with environmental protection measures. If the emission standards cannot be met, neutralization devices are required, and purchasing emission rights from downstream wastewater treatment plants for highly saline wastewater also represents costs. Overall, it is still most cost-effective to use it as a neutralizing agent to neutralize acidic wastewater.

There must be a very reasonable explanation for wanting to recycle such a dilute solution. . So it is estimated that there is no corresponding alkaline wastewater to be treated in the factory; this is the simplest and most direct reason. . If there were alkaline wastewater to be treated, I guess the original poster wouldn’t have posted this; it’s something even a middle school student could do. Hehe.