Method for preparing magnesium carbonate by using magnesium chloride hexammoniate

Technical Field

The invention belongs to the field of recycling six-ammoniate, the six special relates to a method for preparing magnesium carbonate magnesium chloride ammonia.

Background Art

At present, the silane method for producing polycrystalline silicon has produced a large amount of by-product of the six-ammonia magnesium chloride. Six-ammoniate small solubility in water, and under the natural state will continue to release the ammonia, absorbing moisture in the air a deliquescent, large corrosion resistance, affect its storage, although the six-ammonia magnesium chloride can be used as a hydrogen storage material, but there is little consumption, a large number of six-ammoniate by burial method, many enterprises processing, not only can not reasonable to utilize six ammonia magnesium chloride, again causing soil pollution. Patent ZL94194221. X at home and abroad, ZL01126495 . 0, ZL200510028286.5, CN101734693A and CN101983922 deaminized and the like pass through, such as the six high-temperature calcination process for preparing magnesium chloride ammoniate. Complex preparation process, need high temperature to calcine, and inert gas protection. Deliquescent magnesium chloride and the product, a certain corrosion resistance, certain difficulties to the storage.

Magnesiumcarbonate is a very important inorganic chemical raw materials, easy to store, in the field of fine chemicals used as pharmaceutical intermediates, antacids, drying agent, toning agent, carrier, anti- quick medicinal preparation , daily cosmetic additive; useful as additives in the food field, flour modifier, bread bulking agent; in the rubber field as a reinforcing agent, filler; the high-temperature-resistant and fire-proof field is used as the heat-insulating, fire-proof heat insulating material of the high-temperature-resistant, fire-proof paint; at the same time high glass product used for making, magnesium salt, magnesium oxide, and the like.

Content of the invention

The invention the technical problem to be solved by using six is to provide a method for preparing magnesium carbonate magnesium chloride ammonia, the process is simple, high yield, the reaction conditions are easy to control, the by-product generated in the process of ammonia and refrigerating fluid can be recycled, good environmental protection effect, is suitable for industrial production.

A of the present invention using six ammonia method for preparing magnesium carbonate magnesium chloride, including:

(1) the six-ammonia magnesium chloride adding dilute acid dissolving, mixing, adding ammonia water pH=7 the solution, then the sodium bicarbonate is added in the solution, stirring, the reaction liquid obtained; wherein the quality of the diluted acid quality of the six-ammoniate 1-10 times, sodium bicarbonate quality as the quality of the six-ammoniate 3-8 times;

(2) in the reaction liquid 40-100 the heating [...] 1-3 hours, volatilized in the ammonia gas to be absorbed into the absorbing medium;

(3) step (2) the resulting solution is subjected to sedimentation, filtration, the filter residue 60-120 the dry the [...] , drying product, in other words magnesiumcarbonate, the filtrate 50-100 the evaporation concentration under [...] ;

(4) the above-mentioned liquid concentrates at -10-10 the frozen [...] crystallization, filtration, the filter residue is the ammonium salt, filtrate is reused.

Said step (1) in the diluted acid of 5 wt %-25 wt % dilute hydrochloric acid, 5 wt %-65 wt % dilute sulfuric acid or of 5 wt %-45 wt % dilute nitric acid.

The steps (1) to the concentration of ammonia water of 5 wt %-25 wt %.

Said step (1) the stirring time in 10-50 minutes.

Said step (2) the absorption medium is water, saturated salt water, hydrochloric acid solution, sulfuric acid solution or phosphoric acid solution.

Said step (2) of the ammonium salt is ammonium chloride, ammonium sulfate or ammonium nitrate.

Beneficial effects

The process of the invention is simple, high yield, the reaction conditions are easy to control, the by-product generated in the process of ammonia and refrigerating fluid can be recycled, good environmental protection effect, is suitable for industrial production; the resulting magnesiumcarbonate products of rubber products is particularly suitable for being applied in enhancing and thermal insulation for fire protection, it has good application prospects.

Description of drawings

Figure 1 is the process flow diagram of the invention.

Mode of execution

Combining the specific embodiment below, further elaboration of the invention. Should be understood, these embodiment is used to illustrate the invention and are not used to limit the scope of, the invention. In addition should be understood, in reading the content of the after the invention teaches, the technicians of this field can be to the invention for various alteration or modification, these equivalent forms of the same the application falls claim annexed to the limited range of the book.

Embodiment 1

The 19.7g six ammonia magnesium chloride in 500 ml three-mouth flask, by adding the mass fraction is 20 wt % dilute hydrochloric acid of 50g, stirring 30 minutes, by adding the mass fraction is 10 wt % of ammonia, until solution pH=7. The neutral solution is heated to the 60 [...] , slowly adding solid ammonium bicarbonate 100g, stirring 30 minutes. The above-mentioned reaction solution is heated to 80 the [...] , heating 1.5 hours, the volatilization of ammonia, water is injected in through the conduit, be ammonia water, can be reused. After heating is completed, the mixed solution is a centrifugal sedimentation separation, the filter residue is dried to obtain magnesiumcarbonate, filtrate in 90 the evaporate under [...] freezing after concentrating crystallization, the ammonium chloride crystals, the filtrate can be used repeatedly, get magnesiumcarbonate 7.3g, the yield is 86.9 wt %.

Embodiment 2

The 19.7g six ammonia magnesium chloride in 500 ml three-mouth flask, by adding the mass fraction is 20 wt % dilute sulphuric acid of 50g, stirring 40 minutes, by adding the mass fraction of 15 wt % of ammonia, until solution pH=7. The neutral solution is heated to the 60 [...] , slowly adding solid ammonium bicarbonate 100g, stirring 40 minutes. The above-mentioned reaction solution to the temperature the 90 [...] , heating 2 hours, the volatilization of ammonia, water is injected in through the conduit, be ammonia water, can be reused. After heating is completed, the mixed solution is a centrifugal sedimentation separation, the filter residue is dried to obtain magnesiumcarbonate, filtrate in 95 the evaporation [...] freezing after concentrating crystallization, ammonium chloride and ammonium sulfate crystals are obtained, the filtrate can be used repeatedly, get magnesiumcarbonate 7.1g, to yield 84.5 wt %.