Closed circulation technology of using acidic waste water of titanium dioxide by sulfuric acid method for phosphorite pretreatment
A closed cycle technology for acidic waste water, applied in the direction of phosphorus compounds, titanium dioxide, titanium compounds, etc., can solve the problems of high sulfuric acid consumption, high cost, difficult to handle, etc., to reduce the cost of magnesium removal, reduce phosphorus loss, high economy and environmental protection value effect
Active Publication Date: 2017-08-08
SICHUAN LOMON TITANIUM IND CO LTD
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Problems solved by technology
However, since sulfuric acid is a strong acid, it is unavoidable to react with phosphate rock in advance, causing phosphorus loss. At the same time, the mother liquor for magnesium removal contains a large amount of pollutants, which is difficult to handle, and the high consumption of sulfuric acid leads to high costs. It is difficult to promote in actual production.
[0010] For example, in the Chinese patent document whose publication number is CN102992284A, a method for magnesium ammonium phosphate by-product of magnesium ammonium phosphate removal from high-magnesium phosphate rocks is disclosed. Magnesium has the above-mentioned defects, and phosphoric acid is expensive, and it is impossible to implement it in the industry
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[0045] According to the following method, the acid wastewater is used for the pretreatment of phosphate rock and realizes a closed cycle:
[0046] 1. Take high magnesium phosphate rock (P 2 o 5=28%, MgO=5.0%) 1kg, add 2kg of the magnesium removal mother liquor in step 3, carry out wet milling to 100 mesh sieve pass rate 96% with ball mill, inject the ore slurry obtained into the pretreatment tank;
[0047] 2. Add 2.4L of acidic wastewater with pH=3.1 to the pretreatment tank, and perform magnesium removal reaction at 50°C for 30 minutes to obtain a magnesium removal slurry;
[0048] 3. Separating the solid and liquid from the demagnesified slurry, obtaining the demagnesified phosphate rock filter cake and the demagnesified mother liquor, detecting the phosphate rock removal rate, and sending the demagnesified phosphate rock filter cake to the subsequent process to produce feed grade calcium hydrogen phosphate;
[0049] 4. Add lime milk to the magnesification mother liquor wh...
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The invention relates to a production method of feed-grade calcium hydrophosphate and particularly discloses a closed circulation technology of using acidic waste water of titanium dioxide by a sulfuric acid method for phosphorite pretreatment. The closed circulation technology comprises the following steps: a, removing magnesium from phosphorite with the acidic waste water; b, carrying out solid-liquid separation on magnesium removal slurry; c, neutralizing magnesium removed mother liquor; d, carrying out solid-liquid separation on the neutralized slurry, and using a filtrate subjected to clarification for washing coarse metatitanic acid slurry; and e, enabling the acidic waste water to return to the step A to carry out circulation utilization after being supplemented with water. The closed circulation technology has the advantages that 1) the magnesium removal cost and the phosphorus loss of the phosphorite are greatly lowered, and a way of recovering and treating a great quantity of the acidic waste water is found at the same time; 2) a closed circulation method, in which the magnesium removed mother liquor containing a great quantity of impurities is produced as the magnesium is removed from the phosphorite by using the acidic waste water, is provided, and the problem of hindering industrial popularization of the method is solved; and 3) organic combination of a production technology of the titanium dioxide with the sulfuric acid method with the production method of the feed-grade calcium hydrophosphate is realized.
Description
technical field [0001] The invention relates to a production method of feed grade calcium hydrogen phosphate, in particular to a method for pretreatment of phosphate rock in the production process of feed grade calcium hydrogen phosphate. Background technique [0002] Usually, the production process of feed-grade calcium hydrogen phosphate is as follows: use high-grade low-magnesium phosphate rock to react directly with sulfuric acid to obtain wet-process phosphoric acid. Calcium hydrogen phosphate (white fertilizer), a low-cost fertilizer, is purified from impurities such as iron, aluminum, and sulfate in phosphoric acid after one stage of neutralization; the filtrate enters the second stage of neutralization tank, continues neutralization with milk of lime, and filters the filtrate back to make lime Milk and filter cake are air-dried and crushed to become products. Its typical steps can be summarized as follows: [0003] (1) obtain wet-process phosphoric acid by reaction...
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IPC IPC(8): C01B25/32C01G23/053
CPCC01B25/32C01G23/0532
Inventor 代堂军张玉荣姚恒平朱全芳孙润发
Owner SICHUAN LOMON TITANIUM IND CO LTD