On the recovery of titanium dioxide wastewater from sulfuric acid process
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Given the large amount of wastewater generated in the current production of titanium dioxide via the sulfuric acid method, some ideas for wastewater reuse are proposed. I. The pressing water used for the material before entering the kiln (i.e., the material that has been treated with salt) can be reused as water for pulping the material before salt treatment, which allows savings of XT per day; additionally, salt usage can also be reduced. II. The YT wastewater is generated during the second and third washing steps; after suspension removal, it can be used for iron removal in the second washing step. Since the sodium content in the water from the third washing step is high, the second washing step can be divided into two stages: one stage for iron removal and another stage for sodium removal. III. After treatment, the waste acid becomes a saturated calcium sulfate solution; calcium sulfate is slightly soluble, and there is also sodium sulfate. Both of these substances are soluble in water. Therefore, I believe that the treated wastewater can be used for acid leaching, which allows significant water savings on a daily basis. IV. Hey, what are you waiting for?
The washing water from later processing stages is used in earlier stages, \"reallocated for other purposes\" – many companies are doing this. The neutralized water after environmental treatment contains, in addition to substances such as calcium sulfate, some clay and fibrous materials as well (it would be best to conduct a comprehensive analysis; from my experience with PALL’s water quality analyses, fibrous materials are present). It needs to be demonstrated whether it can be used directly in acid leaching water. From a water treatment perspective, it is technically feasible to achieve complete reuse of wastewater after neutralization treatment, but the costs are beyond what companies can bear. Xuzhou Water Treatment is currently working on this project, with pilot units being tested in the company (the cost per ton of water seems to be over 4 yuan). For acid-leaching water, the production volume is 80,000 tons; the daily consumption is roughly 1,800–2,000 cubic meters. It isn’t necessary to reuse external wastewater – this depends on the season... Reducing water consumption per unit of output is a mandatory requirement. It's good to approach things from different angles and pool ideas. But the prerequisite is to make good use of the existing processes and equipment, using them efficiently. Desalinated water, circulating water – the amounts of “oil and water” are all quite significant...
I. The pressing water used for the material before entering the kiln (i.e., the material that has been treated with salt) can be reused as water for pulping the material before salt treatment, which allows savings of XT per day; additionally, salt usage can also be reduced. That seems feasible; some people have already done it. YT wastewater is generated after two or three washes per day, and after removal of suspended solids, it can be used for iron removal in the second wash. You mentioned that the sodium level in the water from the third wash is high; therefore, the second wash can be divided into two stages: one stage for iron removal and the other for sodium removal. This might be tough; theoretically it’s possible, but it doesn’t seem to be simply a matter of high sodium levels. There’s no data available, so it’s not certain. If there’s time, one can conduct some experiments to see. Thirdly, after treatment, the waste acid becomes a saturated calcium sulfate solution; calcium sulfate is slightly soluble, and there’s also sodium sulfate. Both of these substances are soluble in water. Therefore, I believe that the treated wastewater can be used for acid-leaching processes, which can save a lot of water per day. Forget this water. Unless you’re trying to come up with a concept
The second wash water can be used to recycle the water from the powder gas; it is also desalinated water, and it has a higher temperature!
Was it actually done? How much steam is needed for the powder? If I remember correctly, the steam consumption per ton of titanium dioxide powder should be between 1.5 and 2 tons. Is the waste steam extracted by the exhaust fan fed into the secondary washing tank? It’s probably not feasible. Think differently: Heat is needed to heat the desalinated water, and there are many theoretical approaches available, such as utilizing the waste heat from kiln exhaust gases, the cooling water from water-cooled air compressors, or the waste heat from screw air compressors. . .
A portion of the water from the gas-powder condenser can be reused! It’s not the air that’s been drawn out
I was wrong; the exhaust fan draws in the exhaust gas from the dryer, while the condensed water produced by the gas-powder machine can be reused.
The waste heat from the steam powder can be used for many purposes. The water used in the second and third cleaning processes in my factory is heated by the steam left over from the steam powder. There is even a plan to use this heat to warm the packaging material, and that plan will be put into practice in a few months. . .
Has your project started? I would like to ask for advice