●Raw material: It is applicable to various serpentine ores, especially nickel-containing, high silicon serpentine ore;
●Product: High-purity, super-fine flame-retardant fiber-shape magnesium hydroxide, medical (food) grade magnesium hydroxide, electronic grade magnesium hydroxide, oil grade magnesium hydroxide, environmental protection grade magnesium hydroxide, industrial magnesium carbonate, medical food grade magnesium carbonate, industrial magnesium oxide, active magnesium oxide, high-purity magnesium oxide, co-production ferrous oxalate, super-fine silica dioxide and nickel concentrate.
I. Process Introduction
Pulverize serpentine ore to certain fineness, then use circulating decomposition process to decompose and enable the silicon, magnesium, iron and nickel in serpentine ore powder to be transformed into soluble sulfate and enter liquid phase, and achieve mixed solution with major elements of magnesium sulfate, ferrous sulfate, ferric sulfate and sulfuric acid nickel through solid-liquid separation. First feed mixed solution into nickel extraction procedure to extract nickel concentrate, then feed the solution after nickel extraction in iron extraction procedure, through particular process treatment, produce ferrous oxalate product. The solution after iron extraction achieves pure magnesium sulfate solution through further purification. Under certain process conditions, make magnesium sulfate solution react with ammonia or ammonium bicarbonate to produce magnesium hydroxide or basic magnesium carbonate precipitated, then produce magnesium hydroxide fire retardant or magnesium carbonate product through dehydrating, rinsing, modification, whirling, drying, pulverizing and packaging. It is also allowed to take magnesium hydroxide or basic magnesium carbonate as precursor to control different process conditions, and produce different grades of magnesium oxide products through heat treatment. Major element of mother liquid produced during preparation of magnesium slat is ammonium sulfate. This process has developed mother liquid comprehensive utilization technology and device, which can dispose mother liquid to collect ammonia water, and recycle for preparation of magnesium salt. The waste residues generated in acidolysis and separation processes belong to porous silica dioxide, which is used in preparation of sodium silicate or used as foundation to prepare other silicon compounds.
II. Technical Advancement
This process is mature serpentine resources comprehensive utilization technology, which is featured by high resolution ratio of raw ore, comprehensive utilization of accompanying and symbiotic resources in raw ore, high product is additional value and good economic benefits. In particular, preparation process of magnesium hydroxide can reach the domestic advanced level in the aspects of crystalline control, purity control, surface treatment and cost control.
This technology is supported with mature magnesium hydroxide mother liquid disposing system, and ammonia recovery rate is as high as 80%, not only increasing system is economic benefits, but also eliminating environmental pollution caused due to mother liquid discharge. At present, the magnesium hydroxide production enterprise needs to discharge about 20m3 of mother liquid or process effluent when producing 1t of finished products, causing serious influence to the environment. Magnesium hydroxide has become the burden of production enterprises.
This process can perform high value-added comprehensive utilization for other metal and nonmetal resources in raw ore, conduct co-production of ferrous oxalate, super-fine silica dioxide and nickel concentrate while preparing high value-added magnesium compound. It has significant economic benefits, without waste residue or waste water discharge.
III. Market Prospect
The present world has increasingly high requirements for environmental protection, environment-friendly magnesium hydroxide fire retardant is emphasized by all countries. Developed countries have successively made huge investment in research and development and frequently developed international cooperation. Magnesium hydroxide fire retardant has been widely applied in various plastic products, in particular, high performance magnesium hydroxide fire retardant for wire and cable is even popular among consumers. With rapid development of Chinese high molecular industry and constant perfection and improvement of flame-retardant regulations, the demand for fire retardant has increased accordingly. As non-toxic, smoke-restraining environmental protection inorganic fire retardant, magnesium hydroxide is in very urgent need.
Nickel is one very precious non-ferrous metal resource, and nickel concentrate recovery has very high economic value. Take nickel concentrate containing 20% of nickel as example, the current factory price is as high as 28,000 Yuan/T.
Ferrous oxalate is the raw material for preparing new-type power battery anode material - lithium iron phosphate, the present market circulating price is above 12,000 Yuan/T, having extremely considerable benefits.
Precipitated silica dioxide is mainly used in rubber industry, the present market price is 3,500-4,500 Yuan/T, and price of super-fine silica dioxide is as high as 7,000 Yuan/T.
IV. Technical Sources
Autonomous research and development.
V. Technical State:
Industrialization has been realized. Research Institute has industrialized device with daily capacity of 10t serpentine ore, the device can be used in industrialization test. In the meantime, we also undertook the construction of 60,000t/year serpentine raw ore industrialization device in China.
VI. Major Technological and Economic Indicators:
Resolution ratio of raw ore: magnesium oxide ＞97%, iron＞80%, and nickel ＞97%.
Yield: magnesium oxide ＞80%; iron＞75%, nickel ＞70%, and silicon＞90%.
VII. Investment Scale
According to annual production of 1000t flame-retardant grade magnesium hydroxide, equipment investment is 4.5 million Yuan. The scale can be determined according to the actual circumstance.
VIII. Environmental Protection
The process does not have waste residue or waste water discharge, and ammonia is recycled, without causing environmental pollution.
IX. Economic benefits
Total investment for processing1,000kg serpentine raw ore is 4,900 Yuan, and total output is 9,200 Yuan. The economic benefits are significant.
X. Form of cooperation
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.