Take　brine,　magnesium　chloride　or　magnesium　sulfate　as　raw　materials,　and　adopt　ammonia　method　and　magnesium　carbonate　process　to　produce　magnesium　hydroxide　and　magnesium　carbonate.　The　production　process　will　generate　a　good　deal　of　process　effluent　(mother　liquid　and　washing　water),　including　a　good　deal　of　ammonium　chloride　and　sulfuric　acid　ammonia.　One　production　line　with　annual　production　capacity　of　1000t　magnesium　hydroxide　will　discharge　waste　water　not　less　than　10000m3　every　year,　causing　serious　environmental　pollution　and　losses　of　ammonium　resources.　This　process　was　researched　and　developed　in　2005　and　successfully　industrialized　in　2007,　belonging　to　mature　comprehensive　utilization　technology　of　ammonium-containing　waste　water.

I.　Introduction　to　Process:　

Collect　mother　liquid　and　wash　solution　from　magnesium　hydroxide　or　magnesium　carbonate　production　workshop,　react　with　certain　oxide　in　particular　device　neutralization　to　generate　soluble　chloride　or　sulfate　and　volatilize　ammonia.　After　absorption,　produce　ammonia　water　with　ammonia　purity　of　12-18%,　and　recycle　in　magnesium　hydroxide　precipitated.　It　is　also　possible　to　react　with　carbon　dioxide　from　magnesium　oxide　calcination　procedure　through　purification　treatment,　transform　into　ammonium　carbonate　solution,　and　recycle　in　magnesium　carbonate　precipitation.　Ammonium-containing　effluent　reacts　with　certain　oxide,　the　achieved　solution　containing　soluble　chloride　or　sulfate　contains　magnesium　ion　of　certain　concentration,　which　will　return　to　magnesium　hydroxide　or　magnesium　carbonate　production　workshop　and　will　be　used　as　raw　material　for　producing　magnesium　hydroxide　or　magnesium　carbonate.

II.　Process　Features:

1.　Big　handling　ability;

2.　No　environmental　pollution.　This　process　is　different　from　ammonium　steaming　process　takes　lime　milk　as　raw　material.　For　lime　milk　process,　after　completing　ammonium　steaming,　the　produced　residue　is　calcium　chloride　solution　or　calcium　sulfate.　Production　of　calcium　chloride　product　needs　evaporation　and　concentration　of　solution,　causing　high　energy　consumption.　However,　value　of　calcium　sulfate　is　relatively　low,　if　it　is　discharged,　it　will　still　cause　impact　to　the　environment.　This　process　takes　certain　oxide　as　raw　material,　while　achieving　ammonia　water,　it　produces　new　magnesium-containing　solution,　which　is　recycled　in　preparation　of　magnesium　hydroxide　or　magnesium　carbonate,　not　only　substantially　reducing　production　cost,　but　also　fundamentally　solving　environmental　pollution　problem.

3.　This　process　has　developed　recovery　technology　and　device　of　carbon　dioxide　during　magnesium　oxide　calcination,　which　make　the　recovered　ammonia　water　react　with　carbon　dioxide　to　produce　ammonium　carbonate　solution,　and　recycle　in　precipitation　of　magnesium　carbonate,　not　only　eliminating　the　emission　of　carbon　dioxide,　but　also　reducing　production　cost　of　magnesium　carbonate.

III.　Main　Equipment:　

Special　reactor,　ammonia　absorption　device,　filter　unit,　etc.　In　case　of　the　carbon　dioxide　gas　in　production　workshop　of　recovered　magnesium　oxide,　carbon　dioxide　purification　system　and　carbon　dioxide　absorption　(ammonium　carbonate　solution　preparation)　system　should　also　be　installed.

IV.　Main　Economic　and　Technological　Indicators:　

Handling　ability:　50-600m3/day;　

Ammonia　recovery　cost:　60　Yuan　(calculated　based　on　ammonia　water　with　12%　concentration　for　recovering　1t);　

Ammonia　recovery　rate:　75%;　

Concentration　of　magnesium　ion　during　ammonia　recovery:　25-60g/L;　

Carbon　dioxide　recovery　device:　

Carbon　dioxide　recovery　rate:　70%;　

Carbon　dioxide　recovery　cost:　35　Yuan　(calculated　based　on　carbon　dioxide　gas　for　recovering　1t).

V.　Form　of　Cooperation　and　Service　Method:　

Technical　transfer.　Taking　responsibility　for　process　flow　design,　supporting　equipment　of　standard　equipment,　non-standard　equipment　manufacture　design,　equipment is　plane　layout　design,　equipment　installation　design,　pipe　network　design,　equipment　installation　guidance,　equipment　commissioning,　production　commissioning,　training　for　production　engineers,　analysis　staff　and　technicians,　process　operation　specifications,　raw　material　and　product　analysis　method,　and　preparation　of　intermediate　control　analysis　method;　ensuring　output,　yield　and　quality　to　reach　the　standard;　and　undertaking　turn-key　projects.