How to withdraw gold with aqua regia? How to restore the gold withdrawal from aqua regia?

Aqua regia is used to dissolve gold with aqua regia. It is then reduced with anhydrous sodium sulfite.

Aqua regia, which is 3 times the weight of the metal, is added to the impure gold acid-resistant reactor under ventilation conditions, and after the violent reaction, it is heated and evaporated to about 1 5 of the original volume to completely dissolve the gold.

Then add concentrated hydrochloric acid to drive away the free nitric acid until there is no reddish-brown gas, remove and cool, acidify with 5% hydrochloric acid, filter to remove insoluble impurities, and dilute the remaining chloroauric acid solution with distilled water to about 50-100 grams of gold, and make its pH value 1--2.

The chloroauric acid solution is heated to 30-40 degrees, and the sodium bisulfite solution with a concentration of 150 grams is quickly added while stirring until the gold is all reduced to gold powder precipitation, and then the solution is colorless and transparent and then filtered.

Aqua regia uses the oxidation of concentrated nitric acid to form metal ions such as PT, and at the same time uses the coordination of concentrated hydrochloric acid Cl- to form complexes. , thus dissolving ***.

Put pure gold powder and an appropriate amount of soda ash, borax and other chemically pure solvents into the crucible, and smelt it 2-3 times at a high temperature of 1200 degrees to obtain pure gold with a golden yellow color and a purity of more than 99%.

Put ** into a beaker and add 3--4 times aqua regia to dissolve (aqua regia:hydrochloric acid nitric acid volume ratio 3:1).

After dissolving, the gold-containing aqua regia filters out the impurities to obtain a clean aqua regia solution, which is concentrated and evaporated to a viscous state, dropwise added hydrochloric acid to drive up nitrate, and the nitrate is driven until yellow smoke no longer appears when hydrochloric acid is added, and then ferrous sulfate can be added to reduce it.

The sediment is reddish-brown gold dust, which is washed and put into a crucible and melted at high temperature with a gasoline musket or gas musket, and the gold nugget is obtained.

There are usually three ways to withdraw gold from used circuit boards:

One is the cyanide leaching method, cyanide is a highly toxic drug, although this method of gold extraction is more convenient in the process, but there are great problems in both safety and cyanide procurement.

The second is the aqua regia method, the aqua regia method process is more complicated, but relatively safe, and the rate is generally about 90%.

The third is the thioura method, which is slow and the rate is not high, generally only about 75%. Generally, the most commonly used method for gold withdrawals is the aqua regia method.

Waste circuit board gold must go through several processes: deplating - royal water dissolved gold - nitrate - reduction - purification treatment, etc., I after years of practice, the process has been improved, and now the correspondence face-to-face computer board, CPU, mobile phone board, memory module and other electronic waste refining gold, silver, platinum, intact dismantling and selling to the manufacturer again.

Face-to-face teaching, self-contained materials, hands-on teaching, on-the-spot withdrawal. Correspondence sends a full set of technical materials and CD-ROMs, CD-ROMs are recorded for actual operation, and the reagents and tools used are very ordinary and cheap, and are available in chemical stores all over the country.

Aqua regia is a mixture of concentrated nitric acid and concentrated hydrochloric acid in a 1:3 ratio by volume. It has a strong oxidizing ability, can seize electrons in metals, and can oxidize almost all metals, including Au and Pt.

Aqua regia withdrawal method:

Put ** into a beaker and add 3--4 times aqua regia to dissolve (aqua regia:hydrochloric acid nitric acid volume ratio 3:1).

After dissolving, the gold-containing aqua regia filters out the impurities, obtains a clean aqua regia solution, evaporates to a viscous form in concentration, adds hydrochloric acid dropwise to drive up nitrate, and drives up the nitrate until the yellow smoke no longer appears when adding hydrochloric acid, and then can be reduced with ferrous sulfate, the precipitate is reddish-brown gold powder, and the gold powder is washed and put into the crucible and melted at high temperature with a gasoline musket or gas musket, and the gold nugget is obtained.

The reaction equation for dissolving gold in aqua regia is as follows: Au+Hno3+4HCl=H[AuCl4]+NO+2H2O

However, tetrachloroauric acid is unstable and can be decomposed into HCL by heating, and AUCL3 and AUCL3 can continue to be decomposed into AU

Sodium nitrite reacts with tetrachloroauric acid to form sodium tetrachlorogoldrate, from which nitric oxide and nitrogen dioxide cannot be extracted.

It should be diluted or the excess aqua regia should be diluted or neutralized, and then the metal should be replaced with a metal that is more active than gold.

Summary. Dear, I'm glad to answer for you, how to restore the gold extraction from aqua regia: zinc or iron can be used. It is an ordinary displacement reaction, which uses more zinc, and is also reduced with strong reducing agents such as sodium borohydride, NabH4, hydrazine, etc.

Dear, I'm glad to answer for you, how to restore the gold of aqua regia: you can use Xinchun zinc or iron elemental. It is an ordinary displacement reaction, which is resistant to more sliding modes with zinc code, and also reduced with strong reducing agents such as sodium borohydride NabH4 and hydrazine.

Kiss, <>

Knowledge expansion: Aqua regia gold extraction method: Put huang gold into a beaker and add 3--4 times aqua regia to dissolve (aqua regia:

Hydrochloric acid nitric acid volume ratio 3:1). After dissolving, the gold-containing aqua regia is filtered out of impurities, and a clean solution of aqua regia is obtained, which is concentrated and evaporated to a viscous state, dropwise hydrochloric acid is added to drive nitrate, and the nitrate is no longer huangse smoke when hydrochloric acid is added, and then ferrous sulfate can be added to reduce, the precipitate is gold powder of reddish-brown se, and the gold powder is washed and put into the crucible to melt at high temperature with gasoline fire qiang or gas fire qiang, and the obtained is the gold nugget.

Reduction method: heat the chloroauric acid solution to 30--40 degrees; While stirring, quickly add a sodium bisulfite solution with a concentration of 150 g liters; until all the gold is reduced to gold powder and pants precipitate; Then, the solution is allowed to be nucleus-free and then filtered.

In the process of extracting gold from aqua regia, the temperature is kept at 70 degrees Celsius with oxalic acid, or is it flat at the natural temperature after adding oxalic acid?

Kiss, you need to keep the temperature up. <>

Summary. Put ** into a beaker and add 3--4 times aqua regia to dissolve (aqua regia:hydrochloric acid nitric acid volume ratio 3:

1）。After dissolving, the gold-containing aqua regia filters out the impurities, obtains a clean aqua regia solution, evaporates to a viscous form in concentration, adds hydrochloric acid dropwise to drive up nitrate, and drives up the nitrate until the yellow smoke no longer appears when adding hydrochloric acid, and then can be reduced with ferrous sulfate, the precipitate is reddish-brown gold powder, and the gold powder is washed and put into the crucible and melted at high temperature with a gasoline musket or gas musket, and the gold nugget is obtained.

Put ** into a beaker and add 3-4 times aqua regia to dissolve (aqua regia:hydrochloric acid nitric acid volume ratio 3:1).

After dissolving, the gold king water is filtered out of impurities, and a clean Yuntong king aqueous solution is obtained, which is concentrated and evaporated to a viscous state, dropwise added hydrochloric acid to drive up nitrate, and the nitrate is added to the yellow smoke when adding Tanhu hydrochloric acid, and then ferrous sulfate can be added to reduce, the precipitate is reddish-brown gold powder containing quiet color, and the gold powder is washed and put into the crucible to melt at high temperature with a gasoline musket or gas torch, and the gold nugget is obtained.

Is ferrous sulfate tried to add the dosage ratio?

Dear Yes. What is the proportion.

Reduction method: heat the chloroauric acid solution to 30--40 degrees;

While stirring, quickly add a sodium bisulfite solution with a concentration of 150 g liters;

until all the gold is reduced to gold dust precipitation;

Then let the solution be colorless and transparent, and then filter and suffocate.

Aqua regia withdrawal method:

Dissolution In the impure gold acid-resistant reactor, add aqua regia with 3 times the weight of the metal or bend 3 times under ventilation conditions, and after the violent reaction, heat and evaporate to about 1 5 of the original volume to completely dissolve the gold;

Then add concentrated hydrochloric acid to drive away the free nitric acid until there is no reddish-brown gas, remove and cool, acidify with 5% hydrochloric acid, filter to remove insoluble impurities, and dilute the remaining chloroauric acid solution with distilled water to about 50-100 grams of gold, and make its pH value 1--2.

Reduction Heat the chloroauric acid solution to 30--40 degrees, stir while quickly adding the sodium bisulfite solution with a concentration of 150 grams, until the gold is all reduced to gold powder precipitation, and then let the solution be colorless and transparent before filtration.

Purification The precipitate of gold dust obtained by filtration may also adsorb some impurities such as iron compounds, which must be removed to improve the purity of the gold dust. Add 15% hydrochloric acid to the gold powder, heat and stir and boil for 5 minutes, then carefully pour out the acid, 3-5 times, until it does not appear yellow.

Washing and drying.

The purified gold powder is washed repeatedly with distilled water until the solution is neutral pH 7, and then standing, filtering, and drying to obtain pure gold powder.

Smelting Put pure gold powder and an appropriate amount of soda ash, borax and other chemical pure solvents into the crucible, and smelt it 2-3 times at a high temperature of 1200 degrees to obtain pure gold with a golden yellow color and a purity of more than 99%.

It's simple. First heated and evaporated, the components of aqua regia, nitric acid and hydrochloric acid, are volatile acids, all of which are evaporated, and then the gold chloride precipitate is left, which is dissolved in water and replaced with zinc.

After dissolving, the gold-containing aqua regia filters out the impurities, obtains a clean aqua regia solution, evaporates to a viscous form in concentration, adds hydrochloric acid dropwise to drive up nitrate, and drives up the nitrate until the yellow smoke no longer appears when adding hydrochloric acid, and then can be reduced with ferrous sulfate, the precipitate is reddish-brown gold powder, and the gold powder is washed and put into the crucible and melted at high temperature with a gasoline musket or gas musket, and the gold nugget is obtained.

Question: Is ferrous sulfate trying?

What percentage of questions are asked.