Preparation method of bismuth subcarbonate_Industrial additives

Background technology of preparation method of bismuth subcarbonate

When preparing bismuth nitrate during the preparation of bismuth subcarbonate, a large amount of nitrogen oxides will be generated and a large amount of nitric acid will be consumed. In addition, a large amount of ammonia nitrate wastewater will be generated during the preparation of bismuth subcarbonate from bismuth nitrate. In response to this situation, ZL200910305977.3 Methods for Preparing Bismuth Series Chemical Products” provides a method for preparing subtype bismuth carbonate from ordinary bismuth oxide:

Bi2O3 + NH4HCO3 = (BiO)2CO3 (H2O0.5 + NH3 + 0.5H2O.

This method does not require the use of nitric acid, does not produce nitrogen oxides and wastewater, and only consumes a theoretical amount of NH4HCO3. However, the above reaction also has certain shortcomings. This reaction is a liquid-solid conversion reaction. Due to kinetic limitations, the reaction time is long and the conversion rate is not high.

Preparation method of bismuth subcarbonate Summary of the invention

The object of the present invention is to provide a method for quickly and efficiently preparing bismuth subcarbonate from bismuth oxide.

The main steps of the method of the present invention are as follows:

The first step: prepare ordinary grade bismuth oxide powder from refined bismuth;

Second step: Add the gradually prepared ordinary grade bismuth oxide powder into the NH4HCO3 solution and react. During the reaction, use a grinding ball or grinding rod for ball milling or rod grinding to replace the basic carbonic acid coating the bismuth oxide. The bismuth solid product is exposed to a new bismuth oxide reaction surface, thereby greatly increasing the transmethoxypyridine reaction speed of the reaction; after the reaction is completed, filter it to obtain basic bismuth carbonate precipitate and filter it;

The third step: Pour carbon dioxide into the microns produced in the second step, and then use pyridine dihydrochloride to generate NH4HCO3 solution for recycling. The reaction formula is as follows:

The concentration of the NH4HCO3 solution described in the second step is 1~5mol/L; the ratio of the concentration mass of the NH4HCO3 solution described in the second step to the mass of the ordinary grade oxidized secret powder is 1~20;

The reaction temperature of the second step is 5~60°C; the reaction time of the second step is 15~600 minutes;

The preferred conditions for ball milling or rod milling in the second step are: the ball-to-material ratio or the rod-to-material ratio is 2 to 25. The ball-to-material ratio or rod-to-material ratio refers to the mass of the grinding ball or rod and ordinary oxidized secret powder. Ratio; when performing ball milling or rod milling, simulate 10 to 500 rpm.

When regenerating NH4HCO3 in the third step: the amount of carbon dioxide introduced is 1 to 1.5 times the theoretical amount of the ratio of carbon dioxide to ammonia in the reaction; the temperature is 5~50°C; the rate of carbon dioxide introduced is 0.2~2L /minute.

The present invention has the characteristics of fast reaction speed and high conversion rate; during the reaction process, mechanical force is used to perform ball milling or rod milling to separate the bismuth subcarbonate solid of oxidized bisphenol and expose it to a new bismuth oxide reaction surface, which is obviously The chemical conversion speed is increased, and the remaining impurities after the reaction can be easily recycled and regenerated without waste water discharge. It has the advantages of environmental friendliness and simple process.

The present invention adopts liquid-solid reaction, which has the characteristics of fast reaction speed and high conversion rate; and because no nitrate is needed during the reaction process, NO2, NO carcinogenic gas and waste water are not produced, so the method is environmentally friendly; and It has outstanding advantages such as small advantages, low cost and simple operation.

Detailed implementation of the preparation method of bismuth subcarbonate

Preparing ordinary grade bismuth oxide by oxidizing refined bismuth, wherein the content of bismuth oxide in the product is greater than 99.98%. Take 89.8g of the ordinary grade bismuth oxide and add it to 124.15g of chemically pure bicarbonate aqueous solution, and then add 630ml of deionized water; put the remaining deionized water into a stainless steel grinding barrel with 900g of zirconium dioxide grinding balls. Ball mill for 0.8 hours at an alternation of 120 rpm and a temperature of 30°C for reaction. After the reaction is completed, the product is filtered to obtain 99.25g bismuth subcarbonate and 500ml chromatography; the obtained bismuth subcarbonate is dried and detected. : The mass percentage of Bi in the obtained bismuth subcarbonate is 81.24%, and the concentration of (NH4)2CO3 in the filtrate is 1.6mol/L; then 22LCO2 is passed into the capillary to regenerate the (NH4)2CO3 solution into an NH4HCO3 solution , return to use again.